literature review of journal article

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, generate accurate citations for free.

• Knowledge Base

Methodology

• How to Write a Literature Review | Guide, Examples, & Templates

How to Write a Literature Review | Guide, Examples, & Templates

Published on January 2, 2023 by Shona McCombes . Revised on September 11, 2023.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research that you can later apply to your paper, thesis, or dissertation topic .

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates, and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarize sources—it analyzes, synthesizes , and critically evaluates to give a clear picture of the state of knowledge on the subject.

Instantly correct all language mistakes in your text

Upload your document to correct all your mistakes in minutes

Table of contents

What is the purpose of a literature review, examples of literature reviews, step 1 – search for relevant literature, step 2 – evaluate and select sources, step 3 – identify themes, debates, and gaps, step 4 – outline your literature review’s structure, step 5 – write your literature review, free lecture slides, other interesting articles, frequently asked questions, introduction.

• Quick Run-through
• Step 1 & 2

When you write a thesis , dissertation , or research paper , you will likely have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and its scholarly context
• Develop a theoretical framework and methodology for your research
• Position your work in relation to other researchers and theorists
• Show how your research addresses a gap or contributes to a debate
• Evaluate the current state of research and demonstrate your knowledge of the scholarly debates around your topic.

Writing literature reviews is a particularly important skill if you want to apply for graduate school or pursue a career in research. We’ve written a step-by-step guide that you can follow below.

Here's why students love Scribbr's proofreading services

Discover proofreading & editing

Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research problem and questions .

Make a list of keywords

Start by creating a list of keywords related to your research question. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list as you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some useful databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can also use boolean operators to help narrow down your search.

Make sure to read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

You likely won’t be able to read absolutely everything that has been written on your topic, so it will be necessary to evaluate which sources are most relevant to your research question.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models, and methods?
• Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible , and make sure you read any landmark studies and major theories in your field of research.

You can use our template to summarize and evaluate sources you’re thinking about using. Click on either button below to download.

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It is important to keep track of your sources with citations to avoid plagiarism . It can be helpful to make an annotated bibliography , where you compile full citation information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

Receive feedback on language, structure, and formatting

Professional editors proofread and edit your paper by focusing on:

• Academic style
• Vague sentences
• Style consistency

See an example

To begin organizing your literature review’s argument and structure, be sure you understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly visual platforms like Instagram and Snapchat—this is a gap that you could address in your own research.

There are various approaches to organizing the body of a literature review. Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarizing sources in order.

Try to analyze patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organize your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text , your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, you can follow these tips:

• Summarize and synthesize: give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: don’t just paraphrase other researchers — add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically evaluate: mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: use transition words and topic sentences to draw connections, comparisons and contrasts

In the conclusion, you should summarize the key findings you have taken from the literature and emphasize their significance.

When you’ve finished writing and revising your literature review, don’t forget to proofread thoroughly before submitting. Not a language expert? Check out Scribbr’s professional proofreading services !

This article has been adapted into lecture slides that you can use to teach your students about writing a literature review.

Scribbr slides are free to use, customize, and distribute for educational purposes.

Open Google Slides Download PowerPoint

If you want to know more about the research process , methodology , research bias , or statistics , make sure to check out some of our other articles with explanations and examples.

• Sampling methods
• Simple random sampling
• Stratified sampling
• Cluster sampling
• Likert scales
• Reproducibility

 Statistics

• Null hypothesis
• Statistical power
• Probability distribution
• Effect size
• Poisson distribution

Research bias

• Optimism bias
• Cognitive bias
• Implicit bias
• Hawthorne effect
• Anchoring bias
• Explicit bias

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarize yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your thesis or dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

McCombes, S. (2023, September 11). How to Write a Literature Review | Guide, Examples, & Templates. Scribbr. Retrieved April 2, 2024, from https://www.scribbr.com/dissertation/literature-review/

Is this article helpful?

Shona McCombes

Other students also liked, what is a theoretical framework | guide to organizing, what is a research methodology | steps & tips, how to write a research proposal | examples & templates, what is your plagiarism score.

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

Writing a Literature Review

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

How to Write a Literature Review

What is a literature review.

• What Is the Literature
• Writing the Review

A literature review is much more than an annotated bibliography or a list of separate reviews of articles and books. It is a critical, analytical summary and synthesis of the current knowledge of a topic. Thus it should compare and relate different theories, findings, etc, rather than just summarize them individually. In addition, it should have a particular focus or theme to organize the review. It does not have to be an exhaustive account of everything published on the topic, but it should discuss all the significant academic literature and other relevant sources important for that focus.

This is meant to be a general guide to writing a literature review: ways to structure one, what to include, how it supplements other research. For more specific help on writing a review, and especially for help on finding the literature to review, sign up for a Personal Research Session .

The specific organization of a literature review depends on the type and purpose of the review, as well as on the specific field or topic being reviewed. But in general, it is a relatively brief but thorough exploration of past and current work on a topic. Rather than a chronological listing of previous work, though, literature reviews are usually organized thematically, such as different theoretical approaches, methodologies, or specific issues or concepts involved in the topic. A thematic organization makes it much easier to examine contrasting perspectives, theoretical approaches, methodologies, findings, etc, and to analyze the strengths and weaknesses of, and point out any gaps in, previous research. And this is the heart of what a literature review is about. A literature review may offer new interpretations, theoretical approaches, or other ideas; if it is part of a research proposal or report it should demonstrate the relationship of the proposed or reported research to others' work; but whatever else it does, it must provide a critical overview of the current state of research efforts. 

Literature reviews are common and very important in the sciences and social sciences. They are less common and have a less important role in the humanities, but they do have a place, especially stand-alone reviews.

Types of Literature Reviews

There are different types of literature reviews, and different purposes for writing a review, but the most common are:

• Stand-alone literature review articles . These provide an overview and analysis of the current state of research on a topic or question. The goal is to evaluate and compare previous research on a topic to provide an analysis of what is currently known, and also to reveal controversies, weaknesses, and gaps in current work, thus pointing to directions for future research. You can find examples published in any number of academic journals, but there is a series of Annual Reviews of *Subject* which are specifically devoted to literature review articles. Writing a stand-alone review is often an effective way to get a good handle on a topic and to develop ideas for your own research program. For example, contrasting theoretical approaches or conflicting interpretations of findings can be the basis of your research project: can you find evidence supporting one interpretation against another, or can you propose an alternative interpretation that overcomes their limitations?
• Part of a research proposal . This could be a proposal for a PhD dissertation, a senior thesis, or a class project. It could also be a submission for a grant. The literature review, by pointing out the current issues and questions concerning a topic, is a crucial part of demonstrating how your proposed research will contribute to the field, and thus of convincing your thesis committee to allow you to pursue the topic of your interest or a funding agency to pay for your research efforts.
• Part of a research report . When you finish your research and write your thesis or paper to present your findings, it should include a literature review to provide the context to which your work is a contribution. Your report, in addition to detailing the methods, results, etc. of your research, should show how your work relates to others' work.

A literature review for a research report is often a revision of the review for a research proposal, which can be a revision of a stand-alone review. Each revision should be a fairly extensive revision. With the increased knowledge of and experience in the topic as you proceed, your understanding of the topic will increase. Thus, you will be in a better position to analyze and critique the literature. In addition, your focus will change as you proceed in your research. Some areas of the literature you initially reviewed will be marginal or irrelevant for your eventual research, and you will need to explore other areas more thoroughly. 

Examples of Literature Reviews

See the series of Annual Reviews of *Subject* which are specifically devoted to literature review articles to find many examples of stand-alone literature reviews in the biomedical, physical, and social sciences. 

Research report articles vary in how they are organized, but a common general structure is to have sections such as:

• Abstract - Brief summary of the contents of the article
• Introduction - A explanation of the purpose of the study, a statement of the research question(s) the study intends to address
• Literature review - A critical assessment of the work done so far on this topic, to show how the current study relates to what has already been done
• Methods - How the study was carried out (e.g. instruments or equipment, procedures, methods to gather and analyze data)
• Results - What was found in the course of the study
• Discussion - What do the results mean
• Conclusion - State the conclusions and implications of the results, and discuss how it relates to the work reviewed in the literature review; also, point to directions for further work in the area

Here are some articles that illustrate variations on this theme. There is no need to read the entire articles (unless the contents interest you); just quickly browse through to see the sections, and see how each section is introduced and what is contained in them.

The Determinants of Undergraduate Grade Point Average: The Relative Importance of Family Background, High School Resources, and Peer Group Effects , in The Journal of Human Resources , v. 34 no. 2 (Spring 1999), p. 268-293.

This article has a standard breakdown of sections:

• Introduction
• Literature Review
• Some discussion sections

First Encounters of the Bureaucratic Kind: Early Freshman Experiences with a Campus Bureaucracy , in The Journal of Higher Education , v. 67 no. 6 (Nov-Dec 1996), p. 660-691.

This one does not have a section specifically labeled as a "literature review" or "review of the literature," but the first few sections cite a long list of other sources discussing previous research in the area before the authors present their own study they are reporting.

• Next: What Is the Literature >>
• Last Updated: Jan 11, 2024 9:48 AM
• URL: https://libguides.wesleyan.edu/litreview

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• CAREER FEATURE
• 04 December 2020
• Correction 09 December 2020

How to write a superb literature review

Andy Tay is a freelance writer based in Singapore.

You can also search for this author in PubMed   Google Scholar

Literature reviews are important resources for scientists. They provide historical context for a field while offering opinions on its future trajectory. Creating them can provide inspiration for one’s own research, as well as some practice in writing. But few scientists are trained in how to write a review — or in what constitutes an excellent one. Even picking the appropriate software to use can be an involved decision (see ‘Tools and techniques’). So Nature asked editors and working scientists with well-cited reviews for their tips.

Access options

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

$29.99 / 30 days

cancel any time

Subscribe to this journal

Receive 51 print issues and online access

$199.00 per year

only $3.90 per issue

Rent or buy this article

Prices vary by article type

Prices may be subject to local taxes which are calculated during checkout

doi: https://doi.org/10.1038/d41586-020-03422-x

Interviews have been edited for length and clarity.

Updates & Corrections

Correction 09 December 2020 : An earlier version of the tables in this article included some incorrect details about the programs Zotero, Endnote and Manubot. These have now been corrected.

Hsing, I.-M., Xu, Y. & Zhao, W. Electroanalysis 19 , 755–768 (2007).

Article   Google Scholar  

Ledesma, H. A. et al. Nature Nanotechnol. 14 , 645–657 (2019).

Article   PubMed   Google Scholar  

Brahlek, M., Koirala, N., Bansal, N. & Oh, S. Solid State Commun. 215–216 , 54–62 (2015).

Choi, Y. & Lee, S. Y. Nature Rev. Chem . https://doi.org/10.1038/s41570-020-00221-w (2020).

Download references

Related Articles

• Research management

Africa’s postdoc workforce is on the rise — but at what cost?

Career Feature 02 APR 24

Research assessments are still not fit for purpose — here’s how to change things

World View 02 APR 24

How scientists are making the most of Reddit

Career Feature 01 APR 24

Adopt universal standards for study adaptation to boost health, education and social-science research

Correspondence 02 APR 24

How can we make PhD training fit for the modern world? Broaden its philosophical foundations

Allow researchers with caring responsibilities ‘promotion pauses’ to make research more equitable

The corpse of an exploded star and more — March’s best science images

News 28 MAR 24

How papers with doctored images can affect scientific reviews

Nature is committed to diversifying its journalistic sources

Editorial 27 MAR 24

Head of ClinicalTrials.gov

National Institutes of Health (NIH) National Library of Medicine (NLM) National Center for Biotechnology Information (NCBI) Information Engineering...

Washington D.C. (US)

National Library of Medicine, National Center for Biotechnology Information

POSTDOCTORAL FELLOWSHIP IN SYSTEMS BIOLOGY: PRECISION VACCINE PROGRAM (PVP) - BOSTON CHILDREN'

The Data Management and Analysis Core (DMAC) within the Precision Vaccine Program (PVP) at Boston Children’s Hospital and Harvard Medical School (H...

Boston, Massachusetts

Boston Children's Hospital - Department of Pediatrics

2024 Recruitment notice Shenzhen Institute of Synthetic Biology: Shenzhen, China

The wide-ranging expertise drawing from technical, engineering or science professions...

Shenzhen,China

Shenzhen Institute of Synthetic Biology

Global Talent Recruitment (Scientist Positions)

Global Talent Gathering for Innovation, Changping Laboratory Recruiting Overseas High-Level Talents.

Beijing, China

Changping Laboratory

Senior Scientist, Research

Be part of something altogether life-changing!  Working at Cytiva means being at the forefront of providing new solutions to transform human heal...

Vancouver, British Columbia (CA)

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Libraries | Research Guides

Literature reviews, what is a literature review, learning more about how to do a literature review.

• Planning the Review
• The Research Question
• Choosing Where to Search
• Organizing the Review
• Writing the Review

A literature review is a review and synthesis of existing research on a topic or research question. A literature review is meant to analyze the scholarly literature, make connections across writings and identify strengths, weaknesses, trends, and missing conversations. A literature review should address different aspects of a topic as it relates to your research question. A literature review goes beyond a description or summary of the literature you have read. 

• Sage Research Methods Core Collection This link opens in a new window SAGE Research Methods supports research at all levels by providing material to guide users through every step of the research process. SAGE Research Methods is the ultimate methods library with more than 1000 books, reference works, journal articles, and instructional videos by world-leading academics from across the social sciences, including the largest collection of qualitative methods books available online from any scholarly publisher. – Publisher

• Next: Planning the Review >>
• Last Updated: Jan 17, 2024 10:05 AM
• URL: https://libguides.northwestern.edu/literaturereviews

What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

• What is the purpose of literature review? 
• a. Habitat Loss and Species Extinction: 
• b. Range Shifts and Phenological Changes: 
• c. Ocean Acidification and Coral Reefs: 
• d. Adaptive Strategies and Conservation Efforts: 
• How to write a good literature review 
• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• Frequently asked questions 

What is a literature review?

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

What is the purpose of literature review?

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

• Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 
• Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field. 
• Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 
• Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 
• Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 
• Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

a. Habitat Loss and Species Extinction:

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

b. Range Shifts and Phenological Changes:

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

c. Ocean Acidification and Coral Reefs:

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

d. Adaptive Strategies and Conservation Efforts:

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

How to write a good literature review

Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. 

Frequently asked questions

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

Paperpal is an AI writing assistant that help academics write better, faster with real-time suggestions for in-depth language and grammar correction. Trained on millions of research manuscripts enhanced by professional academic editors, Paperpal delivers human precision at machine speed.  

Try it for free or upgrade to  Paperpal Prime , which unlocks unlimited access to premium features like academic translation, paraphrasing, contextual synonyms, consistency checks and more. It’s like always having a professional academic editor by your side! Go beyond limitations and experience the future of academic writing.  Get Paperpal Prime now at just US$19 a month!

Related Reads:

• Empirical Research: A Comprehensive Guide for Academics 
• How to Write a Scientific Paper in 10 Steps 
• Life Sciences Papers: 9 Tips for Authors Writing in Biological Sciences
• What is an Argumentative Essay? How to Write It (With Examples)

6 Tips for Post-Doc Researchers to Take Their Career to the Next Level

Self-plagiarism in research: what it is and how to avoid it, you may also like, do plagiarism checkers detect ai content, word choice problems: how to use the right..., how to avoid plagiarism when using generative ai..., what are journal guidelines on using generative ai..., types of plagiarism and 6 tips to avoid..., how to write an essay introduction (with examples)..., similarity checks: the author’s guide to plagiarism and..., what is a master’s thesis: a guide for..., authorship in academia: ghost, guest, and gift authorship, should you use ai tools like chatgpt for....

• UWF Libraries

Literature Review: Conducting & Writing

• Sample Literature Reviews
• Steps for Conducting a Lit Review
• Finding "The Literature"
• Organizing/Writing
• APA Style This link opens in a new window
• Chicago: Notes Bibliography This link opens in a new window
• MLA Style This link opens in a new window

Sample Lit Reviews from Communication Arts

Have an exemplary literature review.

• Literature Review Sample 1
• Literature Review Sample 2
• Literature Review Sample 3

Have you written a stellar literature review you care to share for teaching purposes?

Are you an instructor who has received an exemplary literature review and have permission from the student to post?

Please contact Britt McGowan at [email protected] for inclusion in this guide. All disciplines welcome and encouraged.

• << Previous: MLA Style
• Next: Get Help! >>
• Last Updated: Mar 22, 2024 9:37 AM
• URL: https://libguides.uwf.edu/litreview

Literature Review Guide: Examples of Literature Reviews

• What is a Literature Review?
• How to start?
• Search strategies and Databases
• Examples of Literature Reviews
• How to organise the review
• Library summary
• Emerald Infographic

All good quality journal articles will include a small Literature Review after the Introduction paragraph.  It may not be called a Literature Review but gives you an idea of how one is created in miniature.

Sample Literature Reviews as part of a articles or Theses

• Sample Literature Review on Critical Thinking (Gwendolyn Reece, American University Library)
• Hackett, G and Melia, D . The hotel as the holiday/stay destination:trends and innovations. Presented at TRIC Conference, Belfast, Ireland- June 2012 and EuroCHRIE Conference

Links to sample Literature Reviews from other libraries

• Sample literature reviews from University of West Florida

Standalone Literature Reviews

• Attitudes towards the Disability in Ireland
• Martin, A., O'Connor-Fenelon, M. and Lyons, R. (2010). Non-verbal communication between nurses and people with an intellectual disability: A review of the literature. Journal of Intellectual Diabilities, 14(4), 303-314.

Irish Theses

• Phillips, Martin (2015) European airline performance: a data envelopment analysis with extrapolations based on model outputs. Master of Business Studies thesis, Dublin City University.
• The customers’ perception of servicescape’s influence on their behaviours, in the food retail industry : Dublin Business School 2015
• Coughlan, Ray (2015) What was the role of leadership in the transformation of a failing Irish Insurance business. Masters thesis, Dublin, National College of Ireland.
• << Previous: Search strategies and Databases
• Next: Tutorials >>
• Last Updated: Feb 27, 2024 4:07 PM
• URL: https://ait.libguides.com/literaturereview

Loading metrics

Open Access

Ten Simple Rules for Writing a Literature Review

* E-mail: [email protected]

Affiliations Centre for Functional and Evolutionary Ecology (CEFE), CNRS, Montpellier, France, Centre for Biodiversity Synthesis and Analysis (CESAB), FRB, Aix-en-Provence, France

• Marco Pautasso

Published: July 18, 2013

• https://doi.org/10.1371/journal.pcbi.1003149
• Reader Comments

Citation: Pautasso M (2013) Ten Simple Rules for Writing a Literature Review. PLoS Comput Biol 9(7): e1003149. https://doi.org/10.1371/journal.pcbi.1003149

Editor: Philip E. Bourne, University of California San Diego, United States of America

Copyright: © 2013 Marco Pautasso. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Funding: This work was funded by the French Foundation for Research on Biodiversity (FRB) through its Centre for Synthesis and Analysis of Biodiversity data (CESAB), as part of the NETSEED research project. The funders had no role in the preparation of the manuscript.

Competing interests: The author has declared that no competing interests exist.

Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications [1] . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively [2] . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests [3] . Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read [4] . For such summaries to be useful, however, they need to be compiled in a professional way [5] .

When starting from scratch, reviewing the literature can require a titanic amount of work. That is why researchers who have spent their career working on a certain research issue are in a perfect position to review that literature. Some graduate schools are now offering courses in reviewing the literature, given that most research students start their project by producing an overview of what has already been done on their research issue [6] . However, it is likely that most scientists have not thought in detail about how to approach and carry out a literature review.

Reviewing the literature requires the ability to juggle multiple tasks, from finding and evaluating relevant material to synthesising information from various sources, from critical thinking to paraphrasing, evaluating, and citation skills [7] . In this contribution, I share ten simple rules I learned working on about 25 literature reviews as a PhD and postdoctoral student. Ideas and insights also come from discussions with coauthors and colleagues, as well as feedback from reviewers and editors.

Rule 1: Define a Topic and Audience

How to choose which topic to review? There are so many issues in contemporary science that you could spend a lifetime of attending conferences and reading the literature just pondering what to review. On the one hand, if you take several years to choose, several other people may have had the same idea in the meantime. On the other hand, only a well-considered topic is likely to lead to a brilliant literature review [8] . The topic must at least be:

• interesting to you (ideally, you should have come across a series of recent papers related to your line of work that call for a critical summary),
• an important aspect of the field (so that many readers will be interested in the review and there will be enough material to write it), and
• a well-defined issue (otherwise you could potentially include thousands of publications, which would make the review unhelpful).

Ideas for potential reviews may come from papers providing lists of key research questions to be answered [9] , but also from serendipitous moments during desultory reading and discussions. In addition to choosing your topic, you should also select a target audience. In many cases, the topic (e.g., web services in computational biology) will automatically define an audience (e.g., computational biologists), but that same topic may also be of interest to neighbouring fields (e.g., computer science, biology, etc.).

Rule 2: Search and Re-search the Literature

After having chosen your topic and audience, start by checking the literature and downloading relevant papers. Five pieces of advice here:

• keep track of the search items you use (so that your search can be replicated [10] ),
• keep a list of papers whose pdfs you cannot access immediately (so as to retrieve them later with alternative strategies),
• use a paper management system (e.g., Mendeley, Papers, Qiqqa, Sente),
• define early in the process some criteria for exclusion of irrelevant papers (these criteria can then be described in the review to help define its scope), and
• do not just look for research papers in the area you wish to review, but also seek previous reviews.

The chances are high that someone will already have published a literature review ( Figure 1 ), if not exactly on the issue you are planning to tackle, at least on a related topic. If there are already a few or several reviews of the literature on your issue, my advice is not to give up, but to carry on with your own literature review,

• PPT PowerPoint slide
• PNG larger image
• TIFF original image

The bottom-right situation (many literature reviews but few research papers) is not just a theoretical situation; it applies, for example, to the study of the impacts of climate change on plant diseases, where there appear to be more literature reviews than research studies [33] .

https://doi.org/10.1371/journal.pcbi.1003149.g001

• discussing in your review the approaches, limitations, and conclusions of past reviews,
• trying to find a new angle that has not been covered adequately in the previous reviews, and
• incorporating new material that has inevitably accumulated since their appearance.

When searching the literature for pertinent papers and reviews, the usual rules apply:

• be thorough,
• use different keywords and database sources (e.g., DBLP, Google Scholar, ISI Proceedings, JSTOR Search, Medline, Scopus, Web of Science), and
• look at who has cited past relevant papers and book chapters.

Rule 3: Take Notes While Reading

If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper. My advice is, while reading, to start writing down interesting pieces of information, insights about how to organize the review, and thoughts on what to write. This way, by the time you have read the literature you selected, you will already have a rough draft of the review.

Of course, this draft will still need much rewriting, restructuring, and rethinking to obtain a text with a coherent argument [11] , but you will have avoided the danger posed by staring at a blank document. Be careful when taking notes to use quotation marks if you are provisionally copying verbatim from the literature. It is advisable then to reformulate such quotes with your own words in the final draft. It is important to be careful in noting the references already at this stage, so as to avoid misattributions. Using referencing software from the very beginning of your endeavour will save you time.

Rule 4: Choose the Type of Review You Wish to Write

After having taken notes while reading the literature, you will have a rough idea of the amount of material available for the review. This is probably a good time to decide whether to go for a mini- or a full review. Some journals are now favouring the publication of rather short reviews focusing on the last few years, with a limit on the number of words and citations. A mini-review is not necessarily a minor review: it may well attract more attention from busy readers, although it will inevitably simplify some issues and leave out some relevant material due to space limitations. A full review will have the advantage of more freedom to cover in detail the complexities of a particular scientific development, but may then be left in the pile of the very important papers “to be read” by readers with little time to spare for major monographs.

There is probably a continuum between mini- and full reviews. The same point applies to the dichotomy of descriptive vs. integrative reviews. While descriptive reviews focus on the methodology, findings, and interpretation of each reviewed study, integrative reviews attempt to find common ideas and concepts from the reviewed material [12] . A similar distinction exists between narrative and systematic reviews: while narrative reviews are qualitative, systematic reviews attempt to test a hypothesis based on the published evidence, which is gathered using a predefined protocol to reduce bias [13] , [14] . When systematic reviews analyse quantitative results in a quantitative way, they become meta-analyses. The choice between different review types will have to be made on a case-by-case basis, depending not just on the nature of the material found and the preferences of the target journal(s), but also on the time available to write the review and the number of coauthors [15] .

Rule 5: Keep the Review Focused, but Make It of Broad Interest

Whether your plan is to write a mini- or a full review, it is good advice to keep it focused 16 , 17 . Including material just for the sake of it can easily lead to reviews that are trying to do too many things at once. The need to keep a review focused can be problematic for interdisciplinary reviews, where the aim is to bridge the gap between fields [18] . If you are writing a review on, for example, how epidemiological approaches are used in modelling the spread of ideas, you may be inclined to include material from both parent fields, epidemiology and the study of cultural diffusion. This may be necessary to some extent, but in this case a focused review would only deal in detail with those studies at the interface between epidemiology and the spread of ideas.

While focus is an important feature of a successful review, this requirement has to be balanced with the need to make the review relevant to a broad audience. This square may be circled by discussing the wider implications of the reviewed topic for other disciplines.

Rule 6: Be Critical and Consistent

Reviewing the literature is not stamp collecting. A good review does not just summarize the literature, but discusses it critically, identifies methodological problems, and points out research gaps [19] . After having read a review of the literature, a reader should have a rough idea of:

• the major achievements in the reviewed field,
• the main areas of debate, and
• the outstanding research questions.

It is challenging to achieve a successful review on all these fronts. A solution can be to involve a set of complementary coauthors: some people are excellent at mapping what has been achieved, some others are very good at identifying dark clouds on the horizon, and some have instead a knack at predicting where solutions are going to come from. If your journal club has exactly this sort of team, then you should definitely write a review of the literature! In addition to critical thinking, a literature review needs consistency, for example in the choice of passive vs. active voice and present vs. past tense.

Rule 7: Find a Logical Structure

Like a well-baked cake, a good review has a number of telling features: it is worth the reader's time, timely, systematic, well written, focused, and critical. It also needs a good structure. With reviews, the usual subdivision of research papers into introduction, methods, results, and discussion does not work or is rarely used. However, a general introduction of the context and, toward the end, a recapitulation of the main points covered and take-home messages make sense also in the case of reviews. For systematic reviews, there is a trend towards including information about how the literature was searched (database, keywords, time limits) [20] .

How can you organize the flow of the main body of the review so that the reader will be drawn into and guided through it? It is generally helpful to draw a conceptual scheme of the review, e.g., with mind-mapping techniques. Such diagrams can help recognize a logical way to order and link the various sections of a review [21] . This is the case not just at the writing stage, but also for readers if the diagram is included in the review as a figure. A careful selection of diagrams and figures relevant to the reviewed topic can be very helpful to structure the text too [22] .

Rule 8: Make Use of Feedback

Reviews of the literature are normally peer-reviewed in the same way as research papers, and rightly so [23] . As a rule, incorporating feedback from reviewers greatly helps improve a review draft. Having read the review with a fresh mind, reviewers may spot inaccuracies, inconsistencies, and ambiguities that had not been noticed by the writers due to rereading the typescript too many times. It is however advisable to reread the draft one more time before submission, as a last-minute correction of typos, leaps, and muddled sentences may enable the reviewers to focus on providing advice on the content rather than the form.

Feedback is vital to writing a good review, and should be sought from a variety of colleagues, so as to obtain a diversity of views on the draft. This may lead in some cases to conflicting views on the merits of the paper, and on how to improve it, but such a situation is better than the absence of feedback. A diversity of feedback perspectives on a literature review can help identify where the consensus view stands in the landscape of the current scientific understanding of an issue [24] .

Rule 9: Include Your Own Relevant Research, but Be Objective

In many cases, reviewers of the literature will have published studies relevant to the review they are writing. This could create a conflict of interest: how can reviewers report objectively on their own work [25] ? Some scientists may be overly enthusiastic about what they have published, and thus risk giving too much importance to their own findings in the review. However, bias could also occur in the other direction: some scientists may be unduly dismissive of their own achievements, so that they will tend to downplay their contribution (if any) to a field when reviewing it.

In general, a review of the literature should neither be a public relations brochure nor an exercise in competitive self-denial. If a reviewer is up to the job of producing a well-organized and methodical review, which flows well and provides a service to the readership, then it should be possible to be objective in reviewing one's own relevant findings. In reviews written by multiple authors, this may be achieved by assigning the review of the results of a coauthor to different coauthors.

Rule 10: Be Up-to-Date, but Do Not Forget Older Studies

Given the progressive acceleration in the publication of scientific papers, today's reviews of the literature need awareness not just of the overall direction and achievements of a field of inquiry, but also of the latest studies, so as not to become out-of-date before they have been published. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies (“sleeping beauties” [26] )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile. Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society.

Inevitably, new papers on the reviewed topic (including independently written literature reviews) will appear from all quarters after the review has been published, so that there may soon be the need for an updated review. But this is the nature of science [27] – [32] . I wish everybody good luck with writing a review of the literature.

Acknowledgments

Many thanks to M. Barbosa, K. Dehnen-Schmutz, T. Döring, D. Fontaneto, M. Garbelotto, O. Holdenrieder, M. Jeger, D. Lonsdale, A. MacLeod, P. Mills, M. Moslonka-Lefebvre, G. Stancanelli, P. Weisberg, and X. Xu for insights and discussions, and to P. Bourne, T. Matoni, and D. Smith for helpful comments on a previous draft.

• 1. Rapple C (2011) The role of the critical review article in alleviating information overload. Annual Reviews White Paper. Available: http://www.annualreviews.org/userimages/ContentEditor/1300384004941/Annual_Reviews_WhitePaper_Web_2011.pdf . Accessed May 2013.
• View Article
• Google Scholar
• 7. Budgen D, Brereton P (2006) Performing systematic literature reviews in software engineering. Proc 28th Int Conf Software Engineering, ACM New York, NY, USA, pp. 1051–1052. doi: https://doi.org/10.1145/1134285.1134500 .
• 16. Eco U (1977) Come si fa una tesi di laurea. Milan: Bompiani.
• 17. Hart C (1998) Doing a literature review: releasing the social science research imagination. London: SAGE.
• 21. Ridley D (2008) The literature review: a step-by-step guide for students. London: SAGE.

Get Started

Take the first step and invest in your future.

Online Programs

Offering flexibility & convenience in 51 online degrees & programs.

Prairie Stars

Featuring 15 intercollegiate NCAA Div II athletic teams.

Find your Fit

UIS has over 85 student and 10 greek life organizations, and many volunteer opportunities.

Arts & Culture

Celebrating the arts to create rich cultural experiences on campus.

Give Like a Star

Your generosity helps fuel fundraising for scholarships, programs and new initiatives.

Bragging Rights

UIS was listed No. 1 in Illinois and No. 3 in the Midwest in 2023 rankings.

• Quick links Applicants & Students Important Apps & Links Alumni Faculty and Staff Community Admissions How to Apply Cost & Aid Tuition Calculator Registrar Orientation Visit Campus Academics Register for Class Programs of Study Online Degrees & Programs Graduate Education International Student Services Study Away Student Support Bookstore UIS Life Dining Diversity & Inclusion Get Involved Health & Wellness COVID-19 United in Safety Residence Life Student Life Programs UIS Connection Important Apps UIS Mobile App Advise U Canvas myUIS i-card Balance Pay My Bill - UIS Bursar Self-Service Email Resources Bookstore Box Information Technology Services Library Orbit Policies Webtools Get Connected Area Information Calendar Campus Recreation Departments & Programs (A-Z) Parking UIS Newsroom Connect & Get Involved Update your Info Alumni Events Alumni Networks & Groups Volunteer Opportunities Alumni Board News & Publications Featured Alumni Alumni News UIS Alumni Magazine Resources Order your Transcripts Give Back Alumni Programs Career Development Services & Support Accessibility Services Campus Services Campus Police Facilities & Services Registrar Faculty & Staff Resources Website Project Request Web Services Training & Tools Academic Impressions Career Connect CSA Reporting Cybersecurity Training Faculty Research FERPA Training Website Login Campus Resources Newsroom Campus Calendar Campus Maps i-Card Human Resources Public Relations Webtools Arts & Events UIS Performing Arts Center Visual Arts Gallery Event Calendar Sangamon Experience Center for Lincoln Studies ECCE Speaker Series Community Engagement Center for State Policy and Leadership Illinois Innocence Project Innovate Springfield Central IL Nonprofit Resource Center NPR Illinois Community Resources Child Protection Training Academy Office of Electronic Media University Archives/IRAD Institute for Illinois Public Finance

Request Info

How to Review a Journal Article

• Request Info Request info for....     Undergraduate/Graduate     Online     Study Away     Continuing & Professional Education     International Student Services     General Inquiries

For many kinds of assignments, like a  literature review , you may be asked to offer a critique or review of a journal article. This is an opportunity for you as a scholar to offer your  qualified opinion  and  evaluation  of how another scholar has composed their article, argument, and research. That means you will be expected to go beyond a simple  summary  of the article and evaluate it on a deeper level. As a college student, this might sound intimidating. However, as you engage with the research process, you are becoming immersed in a particular topic, and your insights about the way that topic is presented are valuable and can contribute to the overall conversation surrounding your topic.

IMPORTANT NOTE!!

Some disciplines, like Criminal Justice, may only want you to summarize the article without including your opinion or evaluation. If your assignment is to summarize the article only, please see our literature review handout.

Before getting started on the critique, it is important to review the article thoroughly and critically. To do this, we recommend take notes,  annotating , and reading the article several times before critiquing. As you read, be sure to note important items like the thesis, purpose, research questions, hypotheses, methods, evidence, key findings, major conclusions, tone, and publication information. Depending on your writing context, some of these items may not be applicable.

Questions to Consider

To evaluate a source, consider some of the following questions. They are broken down into different categories, but answering these questions will help you consider what areas to examine. With each category, we recommend identifying the strengths and weaknesses in each since that is a critical part of evaluation.

Evaluating Purpose and Argument

• How well is the purpose made clear in the introduction through background/context and thesis?
• How well does the abstract represent and summarize the article’s major points and argument?
• How well does the objective of the experiment or of the observation fill a need for the field?
• How well is the argument/purpose articulated and discussed throughout the body of the text?
• How well does the discussion maintain cohesion?

Evaluating the Presentation/Organization of Information

• How appropriate and clear is the title of the article?
• Where could the author have benefited from expanding, condensing, or omitting ideas?
• How clear are the author’s statements? Challenge ambiguous statements.
• What underlying assumptions does the author have, and how does this affect the credibility or clarity of their article?
• How objective is the author in his or her discussion of the topic?
• How well does the organization fit the article’s purpose and articulate key goals?

Evaluating Methods

• How appropriate are the study design and methods for the purposes of the study?
• How detailed are the methods being described? Is the author leaving out important steps or considerations?
• Have the procedures been presented in enough detail to enable the reader to duplicate them?

Evaluating Data

• Scan and spot-check calculations. Are the statistical methods appropriate?
• Do you find any content repeated or duplicated?
• How many errors of fact and interpretation does the author include? (You can check on this by looking up the references the author cites).
• What pertinent literature has the author cited, and have they used this literature appropriately?

Following, we have an example of a summary and an evaluation of a research article. Note that in most literature review contexts, the summary and evaluation would be much shorter. This extended example shows the different ways a student can critique and write about an article.

Chik, A. (2012). Digital gameplay for autonomous foreign language learning: Gamers’ and language teachers’ perspectives. In H. Reinders (ed.),  Digital games in language learning and teaching  (pp. 95-114). Eastbourne, UK: Palgrave Macmillan.

Be sure to include the full citation either in a reference page or near your evaluation if writing an  annotated bibliography .

In Chik’s article “Digital Gameplay for Autonomous Foreign Language Learning: Gamers’ and Teachers’ Perspectives”, she explores the ways in which “digital gamers manage gaming and gaming-related activities to assume autonomy in their foreign language learning,” (96) which is presented in contrast to how teachers view the “pedagogical potential” of gaming. The research was described as an “umbrella project” consisting of two parts. The first part examined 34 language teachers’ perspectives who had limited experience with gaming (only five stated they played games regularly) (99). Their data was recorded through a survey, class discussion, and a seven-day gaming trial done by six teachers who recorded their reflections through personal blog posts. The second part explored undergraduate gaming habits of ten Hong Kong students who were regular gamers. Their habits were recorded through language learning histories, videotaped gaming sessions, blog entries of gaming practices, group discussion sessions, stimulated recall sessions on gaming videos, interviews with other gamers, and posts from online discussion forums. The research shows that while students recognize the educational potential of games and have seen benefits of it in their lives, the instructors overall do not see the positive impacts of gaming on foreign language learning.

The summary includes the article’s purpose, methods, results, discussion, and citations when necessary.

This article did a good job representing the undergraduate gamers’ voices through extended quotes and stories. Particularly for the data collection of the undergraduate gamers, there were many opportunities for an in-depth examination of their gaming practices and histories. However, the representation of the teachers in this study was very uneven when compared to the students. Not only were teachers labeled as numbers while the students picked out their own pseudonyms, but also when viewing the data collection, the undergraduate students were more closely examined in comparison to the teachers in the study. While the students have fifteen extended quotes describing their experiences in their research section, the teachers only have two of these instances in their section, which shows just how imbalanced the study is when presenting instructor voices.

Some research methods, like the recorded gaming sessions, were only used with students whereas teachers were only asked to blog about their gaming experiences. This creates a richer narrative for the students while also failing to give instructors the chance to have more nuanced perspectives. This lack of nuance also stems from the emphasis of the non-gamer teachers over the gamer teachers. The non-gamer teachers’ perspectives provide a stark contrast to the undergraduate gamer experiences and fits neatly with the narrative of teachers not valuing gaming as an educational tool. However, the study mentioned five teachers that were regular gamers whose perspectives are left to a short section at the end of the presentation of the teachers’ results. This was an opportunity to give the teacher group a more complex story, and the opportunity was entirely missed.

Additionally, the context of this study was not entirely clear. The instructors were recruited through a master’s level course, but the content of the course and the institution’s background is not discussed. Understanding this context helps us understand the course’s purpose(s) and how those purposes may have influenced the ways in which these teachers interpreted and saw games. It was also unclear how Chik was connected to this masters’ class and to the students. Why these particular teachers and students were recruited was not explicitly defined and also has the potential to skew results in a particular direction.

Overall, I was inclined to agree with the idea that students can benefit from language acquisition through gaming while instructors may not see the instructional value, but I believe the way the research was conducted and portrayed in this article made it very difficult to support Chik’s specific findings.

Some professors like you to begin an evaluation with something positive but isn’t always necessary.

The evaluation is clearly organized and uses transitional phrases when moving to a new topic.

This evaluation includes a summative statement that gives the overall impression of the article at the end, but this can also be placed at the beginning of the evaluation.

This evaluation mainly discusses the representation of data and methods. However, other areas, like organization, are open to critique.

Why do we trust in online reviews? Integrative literature review and future research directions

Vol.17, no.2 (2023).

https://doi.org/10.5817/CP2023-2-7

Download Citation

• Author biography
• Additional information

Online reviews are an important information source in decision-making processes. Basing decisions on online reviews, however, requires consumers to trust. Consequently, studying trust has become a major research concern. This article provides an integrative literature review of 70 articles published between 2005 and 2021 that, using both quantitative and qualitative approaches, investigated which factors affect trust in the context of online reviews. Results show that research examined 77 different factors for their effect on trust. For most factors—such as integrity of reviewer, quality of argument, and consistency of review with other reviews—, the findings are relatively distinct. The impact of some other factors—such as homophily, two-sidedness of reviews, and emotionality of reviews—is less clear. To synthesize and systematize the results, I develop a conceptual framework based on a model of the online review process. This framework identifies six groups of factors, namely factors related to reviewers, opinion seekers, platforms, communities, option providers, and external actors. On a more general level, the review finds that research uses many different operationalizations of trust, yet rarely embraces more comprehensive concepts of trust. Based on an assessment of the state of the field, I suggest that future research should corroborate, integrate, and expand upon this body of knowledge.

Nils S. Borchers

Institute of media studies, university of tübingen, tübingen, germany.

Nils S. Borchers is a postdoctoral researcher and lecturer at the Chair of Empirical Media Research, Institute of Media Studies at the U of Tübingen. Nils earned his PhD at U of Mannheim and his MA at the U of Münster. His research interests include digital communication, peer-to-peer-communication, strategic communication, and critical advertising studies.

Borchers, N. S. (2021). Online-Bewertungs-Kompetenz: Grundlegende Kompetenzen im Umgang mit Peer-Bewertungen als Informationsquelle in Entscheidungsprozessen [Online review literacy: Fundamental competences in using online reviews as information sources in decision processes]. In M. Seifert & S. Jöckel (Eds.), Bildung, Wissen und Kompetenz(-en) in digitalen Medien [Education, knowledge, and competencies in digital media] (pp. 159-174). Freie Universität Berlin. https://doi.org/10.48541/dcr.v8.9

Ayeh, J. K., Au, N., & Law, R. (2013). “Do we believe in TripAdvisor?” Examining credibility perceptions and online travelers’ attitude toward using user-generated content. Journal of Travel Research , 52 (4), 437–452. https://doi.org/10.1177/0047287512475217

Babić Rosario, A., de Valck, K., & Sotgiu, F. (2020). Conceptualizing the electronic word-of-mouth process: What we know and need to know about eWOM creation, exposure, and evaluation. Journal of the Academy of Marketing Science, 48 (3), 422–448. https://doi.org/10.1007/s11747-019-00706-1

Bae, S., & Lee, T. (2011). Product type and consumers’ perception of online consumer reviews. Electronic Markets, 21 (4), 255–266. https://doi.org/10.1007/s12525-011-0072-0

Baker, M. A., & Kim, K. (2019). Value destruction in exaggerated online reviews: The effects of emotion, language, and trustworthiness. International Journal of Contemporary Hospitality Management, 31 (4), 1956–1976. https://doi.org/10.1108/IJCHM-03-2018-0247

Banerjee, S., & Chua, A. Y. K. (2019). Trust in online hotel reviews across review polarity and hotel category. Computers in Human Behavior , 90 , 265–275. https://doi.org/10.1016/j.chb.2018.09.010

Barber, B. (1983). The logic and limits of trust . Rutgers University Press.

Bartosiak, M. (2021). Can you tell me where to stay? The effect of presentation format on the persuasiveness of hotel online reviews. Current Issues in Tourism, 24 (8), 1109–1122. https://doi.org/10.1080/13683500.2020.1765749

Booth, A., Sutton, A., & Papaioannou, D. (2016) . Systematic approaches to a successful literature review (2nd ed.). Sage.

Bore, I., Rutherford, C., Glasgow, S., Taheri, B., & Antony, J. (2017). A systematic literature review on eWOM in the hotel industry: Current trends and suggestions for future research. Hospitality & Society , 7 (1), 63–85. https://doi.org/10.1386/hosp.7.1.63_1

BrightLocal (2022). Local consumer review survey 2022 . https://www.brightlocal.com/research/local-consumer-review-survey/

Casaló, L. V., Flavián, C., Guinalíu, M., & Ekinci, Y. (2015). Do online hotel rating schemes influence booking behaviors? International Journal of Hospitality Management , 49 , 28–36. https://doi.org/10.1016/j.ijhm.2015.05.005

Cheung, C. M. K., & Thandani, D. R. (2010). The state of electronic word-of-mouth research: A literature analysis. In PACIS 2010 Proceedings (pp. 1580–1587). AIS eLibrary.

Cheung, M. Y., Luo, C., Sia, C. L., & Chen, H. (2009). Credibility of electronic word-of-mouth: Informational and normative determinants of online consumer recommendations. International Journal of Electronic Commerce , 13 (4), 9–38. https://doi.org/10.2753/JEC1086-4415130402

Chevalier, J. A., & Mayzlin, D. (2006). The effect of word of mouth on sales: Online book reviews. Journal of Marketing Research , 43 (3), 345–354. https://doi.org/10.1509/jmkr.43.3.345

Clare, C. J., Wright, G., Sandiford, P., & Caceres, A. P. (2018). Why should I believe this? Deciphering the qualities of a credible online customer review. Journal of Marketing Communications , 24 (8), 823–842. https://doi.org/10.1080/13527266.2016.1138138

Craciun, G., & Moore, K. (2019). Credibility of negative online product reviews: Reviewer gender, reputation and emotion effects. Computers in Human Behavior , 97 , 104–115. https://doi.org/10.1016/j.chb.2019.03.010

de Langhe, B., Fernbach, P. M., & Lichtenstein, D. R. (2016). Navigating by the stars: Investigating the actual and perceived validity of online user ratings. Journal of Consumer Research , 42 (6), 817–833. https://doi.org/10.1093/jcr/ucv047

Dimoka, A. (2010). What does the brain tell us about trust and distrust? Evidence from a functional neuroimaging study. MIS Quarterly , 34 (2), 373–396. https://doi.org/10.2307/20721433

Dou, X., Walden, J. A., Lee, S., & Lee, J. Y. (2012). Does source matter? Examining source effects in online product reviews. Computers in Human Behavior , 28 (5), 1555–1563. https://doi.org/10.1016/j.chb.2012.03.015

Duffy, A. (2017). Trusting me, trusting you: Evaluating three forms of trust on an information-rich consumer review website. Journal of Consumer Behaviour , 16 (3), 212–220. https://doi.org/10.1002/cb.1628

Filieri, R. (2016). What makes an online consumer review trustworthy? Annals of Tourism Research , 58 , 46–64. https://doi.org/10.1016/j.annals.2015.12.019

Flanagin, A. J., & Metzger, M. J. (2013). Trusting expert- versus user-generated ratings online: The role of information volume, valence, and consumer characteristics. Computers in Human Behavior , 29 (4), 1626–1634. https://doi.org/10.1016/j.chb.2013.02.001

Fukuyama, F. (1996). Trust: The social virtues and the creation of prosperity . Free Press.

Geertz, C. (2017). Thick description: Toward an interpretive theory of culture. In The interpretation of cultures: Selected essays (3rd ed., pp. 3–30). Basic Books.

Gefen, D. (2002). Reflections on the dimensions of trust and trustworthiness among online consumers. ACM SIGMIS Database: DATABASE for Advances in Information Systems , 33 (3), 38–53. https://doi.org/10.1145/569905.569910

Gefen, D., Benbasat, I., & Pavlou, P. (2008). A research agenda for trust in online environments. Journal of Management Information Systems , 24 (4), 275–286. https://doi.org/10.2753/MIS0742-1222240411

Gefen, D., Karahanna, E., & Straub, D. W. (2003). Trust and TAM in online shopping: An integrated model. MIS Quarterly, 27 (1), 51–90. https://doi.org/10.2307/30036519

Giddens, A. (1990). The consequences of modernity . Polity.

Gössling, S., Hall, C. M., & Andersson, A.-C. (2018). The manager’s dilemma: A conceptualization of online review manipulation strategies. Current Issues in Tourism, 21 (5), 484–503. https://doi.org/10.1080/13683500.2015.1127337

Grabner-Kräuter, S., & Waiguny, M. K. J. (2015). Insights into the impact of online physician reviews on patients’ decision making: Randomized experiment. Journal of Medical Internet Research , 17 (4), Article e93. https://doi.org/10.2196/jmir.3991

Graf, H. (2018). Media practices and forced migration: Trust online and offline. Media and Communication, 6 (2), 149–157. https://doi.org/10.17645/mac.v6i2.1281

Hardin, R. (1992). The street-level epistemology of trust. Analyse & Kritik, 14 (2), 152–176. https://doi.org/10.1515/auk-1992-0204

Hoffjann, O. (2013). Trust in public relations. In D. Gefen (Ed.), Psychology of trust: New research (pp. 59–73). Nova.

Ismagilova, E., Slade, E., Rana, N. P., & Dwivedi, Y. K. (2020). The effect of characteristics of source credibility on consumer behaviour: A meta-analysis. Journal of Retailing and Consumer Service , 53, Article 101736 . https://doi.org/10.1016/j.jretconser.2019.01.005

Khoo, C. S. G., Na, J.‐C., & Jaidka, K. (2011). Analysis of the macro-level discourse structure of literature reviews. Online Information Review , 35 (2), 255–271. https://doi.org/10.1108/14684521111128032

King, R. A., Racherla, P., & Bush, V. D. (2014). What we know and don’t know about online word-of-mouth: A review and synthesis of the literature. Journal of Interactive Marketing , 28 (3), 167–183. https://doi.org/10.1016/j.intmar.2014.02.001

Kohring, M. (2004). Vertrauen in Journalismus: Theorie und Empirie [Trust in journalism: Theory and empirical evidence] . Universitätsverlag Konstanz.

Kohring, M., & Matthes, J. (2007). Trust in news media: Development and validation of a multidimensional scale. Communication Research , 34 (2), 231–252. https://doi.org/10.1177/0093650206298071

Krueger, F., & Meyer-Lindenberg, A. (2019). Toward a model of interpersonal trust drawn from neuroscience, psychology, and economics. Trends in Neurosciences , 42 (2), 92–101. https://doi.org/10.1016/j.tins.2018.10.004

Lappas, T. (2012). Fake reviews: The malicious perspective. In G. Bouma, A. Ittoo, E. Métais, & H. Wortmann (Eds.), Natural language processing and information systems (pp. 23–34). Springer. https://doi.org/10.1007/978-3-642-31178-9_3

Lewis, J. D., & Weigert, A. (1985). Trust as a social reality. Social Forces , 63 (4), 967–985. https://doi.org/10.1093/sf/63.4.967

Lim, Y.-s., & Van Der Heide, B. (2015). Evaluating the wisdom of strangers: The perceived credibility of online consumer reviews on Yelp. Journal of Computer-Mediated Communication , 20 (1), 67–82. https://doi.org/10.1111/jcc4.12093

Lis, B. (2013). In eWOM we trust. A framework of factors that determine the eWOM credibility. Business & Information Systems Engineering , 5 (3), 129–140. https://doi.org/10.1007/s12599-013-0261-9

Luhmann, N. (1990). Essays on self-reference . Columbia University Press.

Luhmann, N. (2018). Trust and power . Polity (Original work published 1968, 1975).

Maslowska, E., Malthouse, E. C., & Bernritter, S. F. (2017). Too good to be true: The role of online reviews’ features in probability to buy. International Journal of Advertising , 36 (1), 142–163. https://doi.org/10.1080/02650487.2016.1195622

Mayer, R. C., Davis, J. H., & Schoorman, F. D. (1995). An integrative model of organizational trust. Academy of Management Review , 20 (3), 709–734. https://doi.org/10.5465/amr.1995.9508080335

McGeer, V., & Pettit, P. (2017). The empowering theory of trust. In P. Faulkner & T. Simpson (Eds.), The philosophy of trust (pp. 14–34). Oxford University Press.

McKnight, D. H., & Chervany, N. L. (2001). What trust means in e-commerce customer relationships: An interdisciplinary conceptual typology. International Journal of Electronic Commerce , 6 (2), 35–59. https://doi.org/10.1080/10864415.2001.11044235

Meyer, S. B., & Ward, P. R. (2013). Differentiating between trust and dependence of patients with coronary heart disease: Furthering the sociology of trust. Health, Risk & Society, 15 (3), 279–293. https://doi.org/10.1080/13698575.2013.776017

Mishra, A. K. (1996). Organizational responses to crisis: The centrality of trust. In R. Kramer & T. Tyler (Eds.), Trust in organizations: Frontiers of theory and research (pp. 261–287). Sage. https://doi.org/10.4135/9781452243610.n13

Möllering, G. (2001). The nature of trust: From Georg Simmel to a theory of expectation interpretation and suspension. Sociology , 35 (2), 403–420. https://doi.org/10.1017/S0038038501000190

Moran, G., & Muzellec, L. (2017). eWOM credibility on social networking sites: A framework. Journal of Marketing Communications , 23 (2), 149–161. https://doi.org/10.1080/13527266.2014.969756

Morgner, C. (2018). Trust and society: Suggestions for further development of Niklas Luhmann’s theory of trust. Canadian Review of Sociology/Revue Canadienne De Sociologie, 55 (2), 232–256. https://doi.org/10.1111/cars.12191

Mudambi, S. M., & Schuff, D. (2010). What makes a helpful online review? A study of customer reviews on Amazon.com. MIS Quarterly, 34 (1), 185–200. https://doi.org/10.2307/20721420

Ohanian, R. (1990). Construction and validation of a scale to measure celebrity endorsers’ perceived expertise, trustworthiness, and attractiveness. Journal of Advertising , 19 (3), 39–52. https://doi.org/10.1080/00913367.1990.10673191

Ohanian, R. (1991). The impact of celebrity spokespersons’ perceived image on consumers’ intention to purchase. Journal of Advertising Research , 31 (1), 46–54. https://psycnet.apa.org/record/1991-26094-001

Open Science Collaboration (2015). Estimating the reproducibility of psychological science. Science , 349 (6251), Article aac4716. https://doi.org/10.1126/science.aac4716

O’Reilly, K., MacMillan, A., Mumuni, A. G., & Lancendorfer, K. M. (2016). Extending our understanding of eWOM impact: The role of source credibility and message relevance. Journal of Internet Commerce , 15 (2), 77–96. https://doi.org/10.1080/15332861.2016.1143215

Prendergast, G., Ko, D., & Yin, Y. V. S. (2010). Online word of mouth and consumer purchase intentions. International Journal of Advertising , 29 (5), 687–708. https://doi.org/10.2501/S0265048710201427

Rani, A., & Shivaprasad, H. N. (2018). Determinants of electronic word of mouth persuasiveness: A conceptual model and research propositions. Journal of Contemporary Management Research , 12 (2), 1–16. https://www.proquest.com/scholarly-journals/determinants-electronic-word-mouth-persuasiveness/docview/2171578064/se-2

Romero, L. S., & Mitchell, D. E. (2017). Toward understanding trust: A response to Adams and Miskell. Educational Administration Quarterly, 54 (1), 152–170. https://doi.org/10.1177/0013161X17722017

Rotter, J. B. (1971). Generalized expectancies for interpersonal trust. American Psychologist, 26 (5), 443–452. https://doi.org/10.1037/h0031464

Rousseau, D. M., Sitkin, S. B., Burt, R. S., & Camerer, C. (1998). Not so different after all: A cross-discipline view of trust. Academy of Management Review, 23 (3), 393–404. https://doi.org/10.5465/amr.1998.926617

Seckler, M., Heinz, S., Forde, S., Tuch, A. N., & Opwis, K. (2015). Trust and distrust on the web: User experiences and website characteristics. Computers in Human Behavior, 45 , 39–50. https://doi.org/10.1016/j.chb.2014.11.064

Smith, D., Menon, S., & Sivakumar, K. (2005). Online peer and editorial recommendations, trust, and choice in virtual markets. Journal of Interactive Marketing , 19 (3), 15–37. https://doi.org/10.1002/dir.20041

Torraco, R. J. (2005). Writing integrative literature reviews: Guidelines and examples. Human Resource Development Review , 4 (3), 356–367. https://doi.org/10.1177/1534484305278283

Tzieropoulos, H. (2013). The trust game in neuroscience: A short review. Social Neuroscience , 8 (5), 407–416. https://doi.org/10.1080/17470919.2013.832375

Van Der Heide, B., & Lim, Y.-s. (2016). On the conditional cueing of credibility heuristics: The case of online influence. Communication Research , 43 (5), 672–693. https://doi.org/10.1177/0093650214565915

van Dijck, J. (2013). The culture of connectivity: A critical history of social media . Oxford University Press.

Wang, S., Cunningham, N. R., & Eastin, M. S. (2015). The impact of eWOM message characteristics on the perceived effectiveness of online consumer reviews. Journal of Interactive Advertising , 15 (2), 151–159. https://doi.org/10.1080/15252019.2015.1091755

Whittemore, R., & Knafl, K. (2005). The integrative review: Updated methodology. Journal of Advanced Nursing , 52 (5), 546–553. https://doi.org/10.1111/j.1365-2648.2005.03621.x

Wrightsman, L. S. (1991). Interpersonal trust and attitudes toward human nature. In J. P. Robinson, P. R. Shaver, & L. S. Wrightsman (Eds.), Measures of personality and social psychological attitudes (pp. 373–412). Academic. https://doi.org/10.1016/B978-0-12-590241-0.50012-5

Zhang, X., Wu, Y., & Wang, W. (2021). eWOM, what are we suspecting? Motivation, truthfulness or identity. Journal of Information Communication & Ethics in Society, 19 (1), 104–128. https://doi.org/10.1108/JICES-12-2019-0135

Author’s Contribution

This study was devised and conducted by Nils S. Borchers.

Editorial Record

First submission received: September 22, 2021

Revisions received: September 28, 2022 February 20, 2023

Accepted for publication: February 22, 2023

Editor in charge: Lenka Dedkova

Introduction

Online reviews of such diverse “objects” as cameras, hotels, physicians, and university lecturers have become a mass phenomenon. Many internet users search through reviews of peer consumers, peer patients, peer students, etc. before taking decisions so that online reviews have gained a considerable impact in many areas of everyday lives (e.g., Chevalier & Mayzlin, 2006; Maslowska et al., 2017). Basing decisions on online reviews requires the trust of opinion seekers in the evaluations of their peers. Accordingly, trust in and credibility of online reviews are of specific importance for explaining the effects of reviews. However, trusting in online reviewers and their reviews is a high-risk undertaking. For example, the opinion seeker usually lacks information on both the reviewer’s motives to provide the review and the reviewer’s qualification to evaluate the reviewed object. Furthermore, the providers of the reviewed objects benefit from positive evaluations of their offerings and thus have strong incentives to influence reviews in their favor (Lappas, 2012). Yet despite these obstacles, surveys indicate that internet users widely trust online reviews: For example, an US industry survey (BrightLocal, 2022) found that 49 percent of consumers trust online reviews as much as they trust personal recommendations from family and friends.

Studying trust has become a main concern in research on online reviews. As this review article will show, I identified 70 research articles published in peer-reviewed journals that examined trust in online review contexts. However, a focused overview of their findings is still missing. There exist various literature reviews (Bore et al., 2017; C. M. K. Cheung & Thandani, 2010; Ismagilova et al., 2020; King et al., 2014; Rani & Shivaprasad, 2018) and conceptual frameworks (Moran & Muzellec, 2017) that address research on electronic word-of-mouth (eWOM) communication. These works are, however, neither focused exclusively on online reviews nor on trust and credibility. To close this gap, this article sets out to provide an integrative literature review of empirical studies on trust in online review contexts. It contributes to the field by collecting existing findings, offering a framework for organizing these findings, and identifying shortcomings and research desiderata to indicate future research directions. 

Theorizing Trust in Online Review Contexts

In this section, I will put forward a suggestion on how to theorize trust in online review contexts. To do so, I will first introduce my theoretical understandings of online reviews and trust. Then, I will bring the two understandings together to develop a framework for organizing the empirical findings in the field.

Online Reviews

Online reviews are usually discussed as a specific format of eWOM communication. eWOM is defined as “consumer-generated, consumption-related communication that employs digital tools and is directed primarily to other consumers“ (Babić Rosario et al., 2020). eWOM thus serves as an umbrella concept that includes not only online reviews, but also other types of computer-mediated peer-consumer conversations. In contrast to other eWOM formats, online reviews are usually posted on specific online review platforms. These platforms can be both integrated within retailer homepages (e.g., Amazon, Bookings), fan communities (e.g., Metalstorm, The Metal Archives), and social networking sites (e.g., Facebook), as well as created independently (e.g., Yelp, HealthGrades). Online reviews have been defined as “peer-generated product evaluations posted on company or third-party websites” (Mudambi & Schuff, 2008, p. 186). For the current study, I heavily draw on this definition but specify that I consider all studies relevant that examine peer evaluations in the review section of a review platform. These reviews may be posted on an actual platform or generated specifically for a scientific study. It should be noted that this approach leads to an exclusion of online reviews published on individual blogs, e.g., by social media influencers. I decided to exclude these reviews because the conditions under which trust in online reviews emerges on review platforms differs markedly from the conditions under which it emerges on blogs.

Trust is a common social phenomenon that can be observed in many, if not all, areas of everyday life. Yet, when trying to pinpoint trust, the fuzziness of the concept becomes apparent. Many researchers have tackled trust from the perspective of their respective fields and presented a wide range of conceptualizations (see Gefen et al., 2003, for an overview). However, many scholars agree that in a trust relationship, a trustor acts on the grounds of the expectation that a trustee acts in a specific way, although the trustee could also act differently (Barber, 1983; Gefen et al., 2003; Giddens, 1990; Hardin, 1992; Luhmann, 1968, 1975/2018; Möllering, 2001). For example, a consumer (aka the trustor) who reads an online review of a camera might expect that the reviewer (aka the trustee) has collected sufficient information about and gained extensive experience of the camera before publishing a review. The tricky point here is that the trustor cannot be sure whether the trustee actually acts in the expected way. This uncertainty makes trust risky because the trustee could always act differently than expected, but the trustor will find out whether the trustee fulfilled their expectations only after having trusted them (Gefen et al., 2003; Luhmann, 1968, 1975/2018). For example, a consumer buys the particular camera just to find out that the reviewer did not discuss relevant dysfunctionalities and weaknesses. Alternatively, some authors highlight the vulnerability of the trustor as a key characteristic of trust (e.g,. McGeer & Pettit, 2017; Mishra, 1996; Rousseau et al., 1998) and thus emphasize the consequences of entering a relationship whose outcomes are uncertain because they depend on the trustee.

For this review, I chose to draw on a concept that was, at its core, developed by Luhmann (1968, 1975/2018). Luhmann shares the definition of trust relationships that I just introduced. Imperative for the Luhmannian understanding of trust then is the notion of “own selectivity” (Luhmann, 1990). The concept of own selectivity starts from the observation that, in most situations, a person faces more than one option how to act and therefore must make a decision. It highlights that only this person can make the decision. In a next analytical step, Luhmann introduces a second person to the situation to highlight the social consequences of own selectivity. In their actions, the second person depends on the first person and therefore has to find ways to cope with the first person’s own selectivity as the general autonomy to decide what to do. For Luhmann, trust is a mechanism that helps the second person (the trustor) to do so by acting on the grounds of the assumption that the first person (the trustee) will act as expected. Other such mechanisms are, for example, familiarity, contracts, and hope (Kohring, 2004). A consequence of this understanding of trust is that trust is always addressed to another social actor such as online reviewers and not to entities without own selectivity such as online reviews. This position also explains why, in trying to be analytically rigorous, I use the somewhat cumbersome formulation “trust in online review contexts” instead of “trust in online reviews.”

Since trusting is a risky business, trustors try to identify reasons to trust (Kohring, 2004). Such reasons serve as legitimation for entering a trust relationship because they reduce the perceived risk. For instance, in the camera example, the educational background of the reviewer or the conformity of a review with other reviews on the same camera may function as reasons to trust. Reasons to trust usually refer to particular dimensions of trust (Kohring, 2004). While trust is regarded as a multidimensional concept (Gefen, 2002; Lewis & Weigert, 1985; Romero & Mitchell, 2017), there exists less consensus about which dimensions constitute trust. Some authors argue in support of general principles that address the risk and vulnerability of the trustor such as benevolence (McKnight & Chervany, 2001; Romero & Mitchell, 2017), honesty (Fukuyama, 1995; Seckler et al., 2015), or reliability (Mishra, 1996; Rotter, 1971). In contrast, Luhmann (1968, 1975/2018) argues that the dimensions of trust depend on the social context of the trust relationship. That is to say that the dimensions of trust will be different in different social contexts. For example, the dimensions of trust in a writer of online reviews differs from those of trust in a judge or in a politician because online review author, judge, and politician fulfill different functions in society. In this review, I follow this second line of reasoning.

A considerable debate in trust research circles around the question whether trust should be considered a belief, an attitude, an intention, or a combination of these (for an overview, see Gefen et al., 2003). The Luhmannian line of understanding trust brings up yet another possibility: From its perspective, trust can be regarded as a social relation between two (or more) persons. Accordingly, it holds that trust emerges in and through the relationship rather than “residing” in the trustor. This perspective allows to adjourn the debate on belief, attitude, and intention without neglecting its relevance.

Luhmann’s concept of trust has proven to be productive for the study of trust in mediated communication (e.g., Graf, 2018; Hoffjann, 2013; Kohring, 2004). Like any other concept, however, Luhmann’s concept opens specific perspectives while, at the same time, suffering from its blind spots. This is why I want to emphasize that there exist other trust concepts (e.g., Barber, 1983; Giddens, 1990; Lewis & Weigert, 1985; McGeer & Pettit, 2017; Möllering, 2001) that are worth exploring and that will open different perspectives on trust in online review contexts. Beyond the question of which particular concept to adopt, I suggest that engaging with more comprehensive concepts of trust is fruitful because it sharpens the analytical capabilities of research on trust in online review contexts.

Trust in Online Review Contexts

As Duffy (2017) pointed out, there are different forms of trust in online review contexts. To identify relevant trust relationships, I employed a model of the ideal online review process (Figure 1). The model identifies the various actors involved in the review process: An option provider (e.g., camera manufacturer or physician) offers a specific option (e.g., camera that can be bought or health treatment that can be received). A reviewer , who, ideally, has experience with using this option, composes a review to share this experience. The review is (usually) published on a platform, provided by a platform provider (e.g., Amazon or Healthgrades). A community of platform users assesses the quality of the review (e.g., via comments, flagging, helpfulness votes). An opinion seeker who is interested in the option consults the review as part of their decision making on whether to select the option. In addition to reading the review, the opinion seeker might collect further information provided by an external actor , i.e., an actor who is neither associated with the platform nor the option. Note also that the model only captures the most basic operation of the online review process, which is one opinion seeker consulting one review. In most cases, the opinion seeker will consult more than one review and compare the reviews with each other.

Figure 1. Model of the Ideal Online Review Process.

Note. White boxes symbolize actors within the process. Gray boxes symbolize cultural artifacts. Arrows symbolize relations between actors and artifacts. Dotted lines frame the core of the online review process. Note that the model indicates relations only for the ideal case in which all actors act in a way that facilitates the best online review quality.

From the perspective of the opinion seeker, the involvement of other actors poses risks due to each actor’s own selectivity: The opinion seeker cannot know whether these actors act in a way that ensures good review quality and thus might disappoint expectations directed toward them. For example, platform providers might sell specific editing options to option providers, option providers might pay reviewers to write tendentious reviews (Gössling et al., 2018), reviewers might be unconsciously biased toward premium brands (de Langhe et al., 2016), and community members might have different views on what constitutes a helpful review. Because of these risks, the opinion seeker needs to trust in one or more of the involved actors if they consult online reviews as a source of information in the decision-making process. This conclusion implies that trust in online review contexts usually goes beyond the sole trust in the reviewer to also involve other actors as trustees. The model of the online review process provides a framework for organizing research on trust in online reviews. It allows for attribution of the examined factors to specific actors in the online review process, by indicating to whose actor’s selective actions the factor refers.

Considering the various actors also helps to reflect on four distinctive features of trust in online review contexts that, in combination, distinguish this setting from offline settings. First, while pooling recommendations in offline settings usually includes familiar trustees such as friends, family members, and colleagues, trust in online review contexts is directed at anonymous strangers such as reviewers and platform communities (Borchers, 2021). This mechanism allows opinion seekers to benefit from the experiences of other internet users beyond local, temporal, and social constraints, yet it comes at the price of drastically reduced familiarity with the trustees. Second, review platforms allow their users to share experiences and thus facilitate trust between strangers. However, they provide not only the technical infrastructure for the online review process, but also the terms and conditions for publishing and accessing online reviews (van Dijck, 2013). These terms and conditions reflect the commercial interests of platform providers. Third, quality management is delegated to the community and usually takes place only after the publication. This is different from other (offline) sources to which opinion seekers could turn such as travel books when looking for accommodation or consumer safety groups when looking for a new smoothie maker. Fourth, the online review process is expected to be a peer-to-peer communication process (Borchers, 2021). Peer-to-peer communication implies that the roles of reviewer and opinion seeker are generally interchangeable. Consequently, all opinion seekers could also act as reviewers and vice versa. Such role flexibility does not exist in most other social contexts, such as traditional advertising or journalism.

Research Questions

Trust in online reviews has emerged as an eminent topic in the research on eWOM. This review article aims at providing an overview of the state of research. First, it addresses the research designs that researchers apply. Research designs determine what researchers can see. For example, standardized surveys make exactly those attitudes, intentions, behaviors etc. visible that the surveys ask for. In contrast, observations do not predefine what is to see and thus expand the perspective of the researcher, yet they usually fail to see the broader picture beyond individual cases because they focus on only a few participants.

RQ1: Which research designs are applied in studies on trust in online review contexts?

Second, this review examines the theoretical conceptualizations that inform studies on trust in online review contexts. Like methods, theoretical conceptualizations allow researchers to see specific aspects of a phenomenon because they direct the view of the researcher.

RQ2: How do studies on trust in online review contexts conceptualize trust?

While the RQ1 and RQ2 provide information on how researchers produced their findings, the third research question aims at the actual findings and accounts for the factors that explain trust in online review contexts.

RQ3: Which factors have which effects on trust in online review contexts?

Methodological Framework: Integrative Literature Review

To answer the research questions, I conducted an integrative literature review (Whittemore & Knafl, 2005). The integrative literature review “reviews, critiques, and synthesizes representative literature on a topic in an integrated way” (Torraco, 2005, p. 356). It aims at generating a summary of research trends as well as new perspectives and frameworks on the reviewed topic (Khoo et al., 2011; Torraco, 2005). The integrative literature review supports my objectives in going beyond the description of existing research and allowing for the application of a new conceptual framework and the development of future research directions.

Data Collection

An appropriate and comprehensive literature search strategy is important for enhancing the rigor of literature reviews. The strategy should allow identification of all relevant articles to ensure that the review is based on an adequate corpus and can yield accurate results (Whittemore & Knafl, 2005).

Online reviews are studied in different disciplines, such as marketing, communication, psychology, information systems, and tourism. To take the diversity of the research field into account, I considered a variety of established international academic databases: (1) Business Source Premier, (2) Communication & Mass Media Complete, (3) PsycARTICLES, (4) PsycINFO, (5) PSYNDEX, (6) Library Information Science and Technology Abstracts, and (7) Web of Science.

Search Term

The research literature discusses online reviews under various labels. I therefore included alternative labels in the search term by varying (a) the term “online” with “internet,” “digital,” and, as a large share of existing studies is interested in consumer behavior, “consumer;” and (b) the term “review” with “rating” and “recommendation.” In addition, I searched for the term “eWOM” or “electronic word-of-mouth” (in different variants) because eWOM is an umbrella concept that includes online reviews. Furthermore, research on trust relies on two theoretical concepts, trust and credibility (Kohring & Matthes, 2007). As the two terms are closely connected, I decided to include both in the search term. These considerations resulted in the search term displayed in Table 1.

Table 1 . Final Search Term for Integrative Literature Review.

Selection Criteria

I included an article in the corpus of this review if it met the following content criteria: (1) The article explains the perception of trust (or credibility, respectively) in an online review or the reviewer (see section 2.1), i.e., it conceptualizes trust in online review contexts as a dependent or mediating variable. Articles that focused on trust in other social actors, such as brands or platforms, were not included. I also did not consider articles that examined trust exclusively as an independent or moderating variable. (2) The article focuses on online reviews. Articles on other eWOM formats, including blog posts, forum postings, or social media commentaries, were excluded. Articles were also excluded if they studied online reviews posted outside of review platforms. If in doubt whether an article studied online reviews, for example if the article addressed eWOM and did not specify the eWOM format, I excluded it to ensure a clean data set. (3) The article presents the results of an empirical study.

Furthermore, I introduced three formal criteria: (4) The article is published in a peer-reviewed scientific journal. (5) The article is published in English. (6) The article is published before January 1, 2021, the cutoff date of the query.

Article Selection

The full text query yielded 1,418 records in the seven databases. The combined Ebsco databases (databases 1–6) produced 626 hits, and Web of Science produced 792 hits. As the first step, I removed all articles that did not meet the formal criteria. 510 records were published in other formats than in peer-reviewed scientific journals, another 22 records were published in languages other than English, while all remaining articles were published before the cutoff date of the query. Applying the formal criteria thus led to the exclusion of 532 records. I then controlled the remaining 886 records for duplicates. This procedure identified 275 duplicates, reducing the number of records to 611. As the next step, I used the content criteria to decide whether the article should be included in the sample. To do so, I reviewed the title, keywords, and abstract. If this information did not suffice to make a decision, I examined the full text of the article. This procedure yielded to the exclusion of another 541 records. The final sample thus comprised 70 articles (see Appendix A). Figure 2 displays the selection process.

Data Analysis

For data analysis, I followed Whittemore and Knafl’s (2005) instructions for integrative literature reviews. They propose the following procedure: (1) Data reduction : I coded the articles for concepts of trust, theories, methods, examined factors, and results. (2) Data display: I synthesized the data from the individual articles and organized it into subgroups. This process was guided by Kohring’s (2004) concept of trust and the online review process model. I put particular attention to the identification of different factors discussed under the same label and similar factors discussed under different labels. (3) Data comparison: I examined the synthesized findings to identify strengths, shortcomings, and desiderata of the field. I placed emphasis on a critical analysis as described by Torraco (2005). (4) Conclusion drawing: I critically assessed the current state of research to develop future research directions.

Figure 2 . Overview of Article Selection Process.

Note. Adapted from Page et al., 2020 (modified).

Corpus Characteristics and Bibliometrics

I identified 70 articles on trust in online review contexts that met the selection criteria. The first article on the topic was published in 2005, but more profound scholarly interest in the topic started growing only in 2011 (see Figure 3). Articles were published in 43 individual journals (see Table 2). The large number of journals indicates a high fragmentation of the research field. Only five journals published more than two articles on the topic.

Figure 3 . Number of Publications per Year of Articles on Trust in Online Review Contexts.

Note . The database search for this literature review was conducted in early 2021 and covers research activities before January 1, 2021. The database search yielded two articles (Bartosiak, 2021; Zhang et al., 2021) that were registered as online first versions for 2020. These articles have been published in a journal issue in the meantime and are thus displayed as 2021 in this figure.

Table 2 . Journals That Have Published Articles on Trust in Online Review Contexts.

Research Designs

Research on trust in online reviews applies several methods (see Table 3). Experiments are the most employed method by far, followed by standardized surveys. Accordingly, there is a predominance of articles that adopt quantitative approaches (64 articles) over articles that adopt qualitative (2 articles) or mixed quantitative-qualitative designs (4 articles). Using student samples is a common procedure in the field (30 studies), although most studies rely on general population samples (49 studies). The samples demonstrate geographical diversity (see Table 4). Most studied review objects are hotels (21 studies), electronics (e.g., cameras, TV sets; 16 studies), and restaurants (15 studies). Many studies, especially surveys, do not specify a review platform, but adopt platform-independent approaches, while some focus on existing platforms. Platforms studied most often are TripAdvisor (12 studies), Amazon (6 studies), and Yelp (5 studies), which clearly indicates a Western bias.

Table 3 . Methods Applied in Studies on Trust in Online Review Contexts.

  Table 4 . Sample Origins in Studies on Trust in Online Review Contexts.

Conceptualizing and Measuring Trust

Few studies are informed by more comprehensive concepts of trust. Although it is admittedly hard to determine what is a “more comprehensive concept” and when such a concept “informs” a study, I identified eight articles that related to a conceptual work on trust at least on the level of a definition of trust and not only in passing. The works by Mayer et al. (1995; 6 references) and McKnight and Chervany (2001; 5 references) found some resonance in the field. This resonance might result from the fact that the first and widely cited study in the field (Smith et al., 2005) is informed by these works.

Trust is more often conceptualized on the level of its operationalization for empirical inquiries. I therefore examined reported scales and items that were used to measure trust. I identified a total number of 46 scales that have been used in the field. 38 scales draw on items that originate from previous research, i.e., studies either adopting a complete scale or combining different scales, while eight studies used their own scales. Although the scale presented by Ohanian (1990, 1991) was used much more frequently than others (informing 15 articles), the variety of scales again suggests a great heterogeneity of the field. Qualitative studies used wordings that are similar to the wordings of items in quantitative studies. Where articles reported questions from interview guides, there was a tendency to ask respondents for trust or trustworthiness directly rather than breaking the concept down to its various dimensions.

Examined Factors and Their Effect on Trust

Research has examined the impact of 77 factors on the emergence of trust in online review contexts. I used the model of the online review process to systemize these factors by organizing them according to the actors upon whose own selectivity they touch. For most factors, this process should be self-evident. For example, I assigned the experience of the reviewer in writing reviews to the reviewer since experience will help a reviewer to compose a sound review. Experience thus indicates that trusting this particular reviewer might be less risky. Yet for some other factors, this process may appear to have less face validity. For example, I sorted status badges that reviewers can earn on some platforms in the category “platform-related factors” and not “reviewer-related factors.” I did this although one might think that the badge indicates that a reviewer is trustworthy. However, it is the platform provider who decides whether the platform awards such badges, who determines what the criteria are for acquiring a badge, and who ensures a robust award process. The same logic applies to some of the factors that I systemized as “community-related.” For example, whether a particular review is consistent with other reviews of the same review object depends on the decision that the other reviewers made when writing their reviews. These other reviewers constitute the community. Obviously, the particular reviewer can also tune in the review to the community’s voice. From the perspective of the opinion seeker, however, the other reviews constitute the background against which to assess the consistency of a particular review. The opinion seeker thus has to determine how to respond to this background: Should they base their own assessment of the particular review on these other reviews, or should they discard them? In other words: The opinion seeker has to decide whether to trust in the community. I therefore categorized the consistency of a particular review with other reviews as a community-related factor.

Reviewer-Related Factors

The most exhaustively studied actor in the field is the reviewer. The opinion seeker’s perception of the reviewer’s states and traits is informed by the review that the reviewer wrote as well as by other information that the reviewer provides on the platform, usually when adding information to the user profile. Table 5 presents the reviewer-related factors that have been examined. Research literature often treats review characteristics independently from the reviewer. However, the reviewer is the author of the review and the review depends on their own selectivity. For example, Bannerjee and Chua (2019) examined how the attractiveness of review titles impacts trust but essentially, it is the reviewer who concocts this title. Table 6 presents the findings on review-related factors as a subset of reviewer-related factors.

Table 5 . Examined Reviewer-Related Factors a .

Table 6 . Examined Review-Related Factors a .

Option Provider-Related Factors

The impact of the provider of the reviewed option has been examined only rudimentarily (see Table 7). Notably, Bae and Lee (2011) found that the type of review object influences trust relationships. This factor should be treated with consideration. While the option provider decides which type of options they offer at a market, the review object itself is not an actor in its own right and thus does not possess own selectivity. According to the trust concept informing this literature review, the type of review object should thus rather be theorized as moderator variables than as independent variable.

Table 7 . Examined Option Provider-Related Factors a .

Platform-Related Factors

Research has examined factors that refer to (1) the platform provider as an actor in the online review process and (2) to the information that a platform offers about other actors. For example, platforms might use algorithms to create meta-information, such as marking suspected non-authentic reviews and reporting the status of a platform user. An understanding of studied platform factors can be gained from Table 8.

Community-Related Factors

With regard to the community, research has focused on two different types of factors: (1) meta-information provided by the community that relates to the quality assessment of the specific review via comments or recommendation ratings (e.g., usefulness and helpfulness), and (2) context information that is derived from considering the specific review and its author within the platform environment, such as the consistency of the specific review with other reviews on the same object or the total number of reviews on the object. Table 9 provides an overview on examined community factors.

Table 8 . Platform-Related Factors a .

  Table 9 . Examined Community-Related Factors a .

External Actors-Related Factors

External actors have only occasionally been considered in the field. The little interest in these factors is not surprising, given that external actors remain outside the core online review process. Table 10 summarizes the findings on this factor category.

Table 10 . Examined External Actor-Related Factors a .

Opinion Seeker-Related Factors

Individual characteristics of the opinion seeker can be associated with their willingness to trust. Studies examined the effects of knowledge, states, and, most often, traits on trust in online review contexts (see Table 11).

Table 11. Examined Opinion Seeker-Related Factors a .

Assessment of the State of Research

Research on online reviews has examined a considerable number of factors and how they influence trust. Figure 4 provides an overview of examined factors and their frequency of their consideration in research. For most factors, the findings are relatively distinct, whereas the impact of some others is less clear. In general, however, the field appears to be rather fragmented and heterogeneous. Research uses many different operationalizations of trust and is spread over various journals and disciplines.

The Role of Theory

This literature review set out to synthesize and systemize the existing findings. At the same time, however, the review also brings to light some of the field’s theoretical shortcomings and empirical gaps. Based on this analysis, the main shortcoming of previous research is a certain lack of awareness and reflection of the research’s formal object “trust” (or “credibility,” respectively). In general, the reviewed studies do not refer to comprehensive concepts of trust (e.g., Barber, 1983; Giddens, 1990; Kohring, 2004; Lewis & Weigert, 1985; Luhmann, 1968, 1975/2018; Möllering, 2001) that could more accurately capture the complexity of trust relationships and help interpret the results. This finding echoes a longstanding dissatisfaction with the state of empirical trust research in general. Already in 1991, Wrightsman (1991, p. 411) cautioned that “the general concept of trust deserves much more theoretical analysis. Measurement has advanced more rapidly than conceptual clarification.” Ten years later, McKnight and Chervany (2001, p. 38) emphasized that in the absence of such theoretical analysis, “the plethora of empirical studies (…) has brought trust research to so confusing a state.” For the sake of this review article, I adapted the trust concept advanced by Luhmann (1968, 1975/2018) and other authors following in his footsteps (e.g., Kohring, 2004; Meyer & Ward, 2013; Morgner, 2018) to the online review context. This is not to say that the line of reasoning on trust that I drew on is the only possible line for informing research on trust in online review contexts. Every theoretical perspective enables researchers to see certain aspects while obscuring others, as does this. Nevertheless, my conceptual choice permits the identification of some unfortunate consequences that result from the scarce engagement with trust concepts.

Figure 4 . Considered Factors in Research on Trust in Online Reviews.

Note. Size of bubble corresponds to frequency of consideration (number of studies) of the factor in research on trust in online reviews.

This review brings to light some of the field’s theoretical shortcomings. First, its scarce engagement with trust concepts leads to a fuzzy understanding of who or what the trustor trusts in. Two trust objects are referenced in the studies, the reviewer and the review itself, and sometimes both. The theoretical foundation proposed here could help to resolve this issue. For example, I argued above that trust refers to the own selectivity of actors and that therefore, trust in online reviews should analytically be attributed to their actions. Unsurprisingly, studies consistently report significant correlations between trustworthiness of reviewer and trust in reviews (e.g., M. Y. Cheung et al., 2009; Clare et al., 2018). Furthermore, the online review process model revealed that there are more actors involved in the process than only reviewer and opinion seeker so that the emergence of trust relationships becomes more complex.

Second, the scarce engagement impacts the possibilities to interpret data in meaningful ways. On the one hand, many scales are imported from research on trust in social contexts other than online reviews. From the perspective of the trust concept adopted in this article, trust depends on expectations that are specific for a social context so that dimensions of trust potentially differ from context to context. This perspective thus increases sensitivity for the risk that imported scales might result in neglecting the peculiarities of trust in online reviews. For instance, the scale used most frequently in the field (Ohanian, 1990, 1991) measures trustworthiness of celebrity endorsers in an advertising and marketing context. It seems at least debatable whether trustors’ expectations about celebrity endorsers are similar to their expectations about online reviewers. For example, different from celebrity endorsers, online reviewers are expected to be independent from the option provider. On the other hand, I found that there is a great heterogeneity of items to measure trust. This heterogeneity makes it difficult to compare findings across studies. The trust concept adopted here can inform the operationalization of trust and protect research from inconsistencies when composing scales of items that relate to trust in different ways, for example to dimensions of trust, reasons to trust, and abstract synonyms of trust (e.g., Ayeh et al., 2013; Dou et al., 2012).

Third, the scarce engagement sometimes obscures how factors relate to one another. For example, I found that in some reviewed studies, manifestations of certain dimensions of trust are actually conceptualized as independent variables, i.e., antecedent of trust. For example, Banerjee and Chua (2019) study the credibility of descriptions as an antecedent of trust. Following Kohring’s (2004) concept of trust, this factor can be identified not as an antecedent but rather as an element of trust because it directly refers to a particular trust dimension that he conceptualizes as “trust in the accuracy of descriptions.”

Fourth, this shortcoming restricts the generalization of research findings. Without an appropriate theoretical foundation that helps clarify the conditions for legitimate generalizations, the validity of findings remains limited to the specific context in which the data was generated. For instance, it remains unresolved whether it is possible to transfer findings from a study on online reviews of hotels to reviews of physicians or electronics.

Empirical Gaps

Besides these conceptual challenges, this literature review identified some empirical gaps. First, many factors and factor combinations have only been examined in one or a very limited number of studies, with regard to single review objects (e.g., restaurants, physicians, films), on one platform, and in one cultural context. Moreover, a substantial number of studies uses student samples. In the face of a lasting replication crisis in social and life sciences (Open Science Collaboration, 2015), a more stable empirical validation of some findings appears preferable.

Second, research has examined the factor categories with different degrees of diligence. Whereas the reviewer and the opinion seeker received much attention, the situation is different for the other actors who are involved in the process. The focus on reviewer and opinion seeker is understandable because these two actors can be said to constitute the basic dyad in online review contexts. As the model of the review process illustrates, however, the other actors also play a role in the emergence of trust.

Third, little is known on how different factors interact with one another. While there are studies that examine interactions (e.g., Craciun & Moore, 2019; Flanagin & Metzger, 2013), a more systematic, comprehensive, and coordinated approach to determining interactions is missing.

Fourth, most studies adopt a deductive approach to identify factors that might possibly be related to trust in online reviews. Exploratory approaches do exist in the field (e.g., Clare et al., 2018; O’Reilly et al., 2016), yet are rare. If accepting the theoretical foundations of this review, trust should be considered as directed toward expectations about other actors’ behaviors that are specific to the social context in which trust relationships emerge (Kohring, 2004). A lack of exploratory studies might consequently result in overlooking relevant factors that are specific to online review contexts and thus cannot be derived from research on trust in other contexts.

Future Research Directions

Based on the analysis of strengths, shortcomings, and gaps, I want to propose three endeavors that I think are worthwhile for advancing the field.

Corroborating the Body of Knowledge

Research findings for most factors are unambiguous. The fact, however, that many factors or factor combinations have been examined only once and in specific online review environments, on specific platforms, and in specific cultural contexts calls for replication studies. Moreover, more comparative studies are needed. Researchers can corroborate initial insights by examining if, for example, the relevance of factors that determine opinion seekers’ willingness to trust differs between decisions to buy a plant detergent and to visit a physician or between Northern American and Eastern Asian cultures.

There are some factors for which the evidence is not clear. These include: non-benevolent motives of the reviewer, homophily (reviewer-related factors), correctness of orthography, quality of review, two-sidedness of review, emotionality of review, trustworthiness of descriptions in the review (review-related factors), trustworthiness of platform, reviewer status indication (platform-related factors), receptive attitude of opinion seeker, and experience of opinion seeker with reviews (opinion seeker-related factors). There are many possible reasons why studies yield diverging results. For example, different review objects, platform environments, or cultural backgrounds might explain differences. In some cases, diverging results may also be due to study designs. In still other cases, diverging results might follow from different operationalizations of trust. The fact that the studies usually differ in more than just one aspect makes it difficult to pinpoint the exact reasons that led to diverging results. Moreover, in the cases of the ambiguous factors, the number of studies—and thus the available data basis—is simply too small to identify patterns and reach informed conclusions. Here, further studies are needed to more precisely determine the influence of these factors. A promising starting point is to explore these factors in qualitative studies that allow to address the respective factors in more detail. For example, adopting thought elicitation techniques such as the think aloud method allows researchers in the field to explore the considerations of opinion seekers while engaging with online reviews.

Interestingly, it is sometimes the qualitative studies that yield contradictory findings. For example, while the majority of studies finds that positive valence increases trust, the qualitative studies by Filieri (2016) and Prendergast et al. (2010) demonstrate that positive valence can also have negative effects on trust if reviews become overly positive. While qualitative studies usually do not claim generalizability of their findings, they still can yield detailed and differentiating insights into the effects of specific factors. In particular, this example shows that it might be instructive to reconsider whether identified effects of factors such as valence are indeed linear.

Integrating the Body of Knowledge

It is necessary to integrate the existing findings from different disciplines that are interested in trust in online review contexts to overcome the fragmentation of the research field. Respective attempts might help to better pool resources because the integration of findings makes it easier to identify true research gaps. To tackle the fragmentation, the framework presented in this article might be further refined and adjusted to more specific research interests. Another promising approach to integrate findings might be meta-analyses because this method allows researchers to determine the effect strengths of trust factors across various quantitative data sets. A key challenge in such an undertaking will, however, be the great heterogeneity in operationalizing trust.

Extending the Body of Knowledge

Extending knowledge on trust in online review contexts is a more extensive task. Regarding the theoretical rigor of research, I suggest that engaging with comprehensive concepts of trust (e.g., Barber, 1983; Giddens, 1990; Kohring, 2004; Lewis & Weigert, 1985; Luhmann, 1968, 1975/2018; McGeer & Pettit, 2017; Möllering, 2001) beyond the level of measures and scales provides a more solid foundation for understanding trust in online review contexts. Researchers need to adjust these concepts to online reviews as a specific context. Specifically, the online review process does not only include reviewer and opinion seeker, but also option provider, platform provider, community, and external actors. All of these actors have their own selectivity and, consequently, they influence the emergence of trust relationships.

With regard to empirical directions, I identify three worthwhile directions for extending the body of knowledge. First, experiments and standardized surveys dominate the field. While these two methods are perfectly apt for studying trust in online reviews, I nevertheless want to argue for a greater methodical variety and a stronger consideration of qualitative approaches, such as problem-centered interviews, Q methodology, think alouds, and virtual ethnographies. Due to their open and exploratory character, qualitative approaches allow identifying factors that are specific to trust in online reviews (Clare et al., 2018). Furthermore, by allowing for a greater consideration of individual rationales, qualitative approaches might yield “thick descriptions” (Geertz, 2017) that help contextualize findings. Another promising approach to advance the field is the use of cognitive neuroscience. Various commentators have highlighted the potential of cognitive neuroscience for trust research (Dimoka, 2010; Gefen et al., 2008). This potential has not yet been tapped in the context of online reviews. The approach rests upon the finding that trust, as well as distrust, spans distinct brain areas (Dimoka, 2010). Researchers have successfully applied neuroscientific procedures to general trust research (Tzieropoulos, 2013), and Krueger and Meyer-Lindenberg (2019) proposed a trust model based on neuroscientific findings. These pioneer works hold the potential to add an innovative angle to the study of trust in the context of online reviews.

Second, it is likely that there exist various types of opinion seekers that differ in the importance they attach to specific factors. While one opinion seeker’s willingness to enter a trust relationship may largely depend on, for example, review valence, emotionality, and prior experience with other reviews, these factors might be of minor importance to other opinion seekers. Duffy (2017) suggests opinion seekers’ trust in their own benevolence and integrity as a possible distinguishing feature. There might also exist various types of opinion seekers regarding different usage situations, e.g., decisions on different review objects or decisions made on mobile devices and on-the-go. I encourage researchers to pay more attention to specific opinion seeker types and usage situations. To tackle this task, explorative approaches should prove instructive as a first step. For instance, the Q methodology allows researchers to reconstruct individual perspectives on trust in online reviews and, on this basis, determine what unites opinion seekers who share common viewpoints.

Third, trust relations emerge and grow over time as they unfold within interaction histories. Since the body of reviewers is multitudinous and reviewers often remain anonymous beyond some basic profile information, it seems unlikely that interaction histories unfold between individual peers in general. Nevertheless, opinion seekers gather experience with platforms and platform communities. I propose that these experiences will have a noticeable impact on the emergence of trust. The opinion seeker’s familiarity with a platform has been examined by three studies (Casaló et al., 2015; Lim & Van Der Heide, 2015; Van Der Heide & Lim, 2016), but in general we know little about how prior experiences with platform and platform communities impact trust. This situation motivates two suggestions: First, future study designs should control for prior experiences of opinion seekers. Second, given the dearth of longitudinal studies in the field, researchers should apply designs that allow tracing the formation of trust around specific platforms and their communities over time.

Limitations

The quality of literature reviews crucially depends on the corpus on which they are based (Whittemore & Knafl, 2005). Although I carefully searched for relevant studies, using a broad search term and databases from various disciplines, I cannot guarantee that I identified every academic publication on trust in online reviews. The formal exclusion of non-peer reviewed journal articles and articles published in languages other than English constitutes an obvious limitation. Furthermore, I synthesized the findings on a rather high level of abstraction. It could be argued that the individual factors that constitute categories in this review should be less condensed. I opted for this level of abstraction because the operationalization of most factors was sufficiently similar to group them into one category. However, a more granular systematization might yield a more detailed picture of the state of research. Finally, this review adopted a strict focus on articles that study trust (or credibility) as a dependent or mediating variable. I did not, however, consider the outcomes of trust relationships like purchase intentions (e.g., S. Wang et al., 2015), review adoption (Lis, 2013), attitude toward the review object (e.g., Grabner-Kräuter & Waiguny, 2015), or willingness to re-visit specific online review platforms (Baker & Kim, 2019). Likewise and to avoid “scope creep” (Booth et al., 2016, p. 98), I did not consider concepts that are or might be related to trust, most notably usefulness and helpfulness of reviews (Clare et al., 2018). Future literature reviews on these concepts might help to draw a more comprehensive picture of the role of trust in the online review process.

Conflict of Interest

The author has no conflicts of interest to declare.

Acknowledgement

The author thanks Sevda Can Arslan (Paderborn University) for her involvement with an early outline of this mansuscript that we presented at the 2016 Annual Conference of the Digital Communication division of the German Communication Association in Braunschweig, Germany. The author also thanks the editorial team of Cyberpsychology: Journal of Psychosocial Research on Cyberspace as well as five anonymous reviewers for sharing their helpful advice and support

Full appendices are available in the pdf version of the manuscript.

Crossref Cited-by

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License .

Copyright © 2023 Nils S. Borchers

CASE REPORT article

Gastric paraganglioma: a case report and review of literature.

• 1 Department of Surgery, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
• 2 Department of Pathology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
• 3 Department of Radiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China

Paragangliomas (PGLs) are rare neuroendocrine tumors which overproduce catecholamines (CAs). They are extra-adrenal, catecholamine-secreting tumors occurring outside the adrenal glands. Gastric PGLs originating from extra-adrenal paraganglia are exceptionally rare, and their presentation in geriatric patients further adds to the complexity of diagnosis and management. A 72-year-old male patient presented with enduring left upper abdominal pain and anemia persisting for over a year, and hypertension for six months. Physical examination revealed epigastric discomfort and pallor. Computed tomography scans revealed enlarged lymph nodes in the lesser curvature of the stomach and thickening of the gastric antrum wall with concavity. The patient underwent three cycles of neoadjuvant therapy before radical gastrectomy for gastric cancer. These imaging findings were confirmed during surgery and intraoperative blood pressure was in fluctuation. After the successful resection of the tumor, postoperative pathology confirmed paraganglioma. During postoperative examination, it was observed that the patient’s CAs and their metabolites had returned to within the normal range. Combined with the existing ten literatures, we retrospective report the clinical and pathological characteristics and treatment strategies of the rare gastric paraganglioma.

1 Introduction

PGLs are uncommon neuroendocrine tumors originating from neural crest cells within the sympathetic and parasympathetic nervous systems ( 1 ). They are typically classified into sympathetic and parasympathetic subtypes, with most sympathetic subtypes being functional, secreting CAs. In patients with catecholamine hypersecretion, most tumors locate at the abdomen and pelvis. Only 3.6% of head and neck PGLs were documented to have catecholamine hypersecretion ( 2 ). These tumors represent a subset of pheochromocytomas, comprising approximately 10-18% of all cases, with around 5-10% occurring outside the adrenal glands ( 3 ). Gastric PGLs are exceptionally rare, with a five-year survival rate below 5% ( 4 ). Histologically, PGLs are characterized by a distinctive “Zellballen” pattern, consisting of spindle-shaped and epithelioid cells. While PGLs have been documented in various anatomical sites such as the head and neck, rectum, liver, and bladder organs, cases of gastric PGLs are exceedingly rare ( 5 – 8 ). Sympathetic PGLs, especially those outside the adrenal glands, are frequently functional and tend to produce norepinephrine rather than epinephrine. Patients often present with hypertension and classical symptoms, including headaches, palpitations, and sweating. Notably, most cases of sympathetic PGLs have a familial component and are linked to genetic mutations ( 9 ). Despite the documentation of PGLs in diverse locations, reports of gastric PGLs remain sporadic. Herein, we present a rare case of gastric paraganglioma, contributing to the limited existing literature on this unusual entity.

2 Case presentation

A 72-year-old male patient presented with a persistent history of left upper abdominal pain and anemia spanning over a year. Furthermore, he had developed hypertension six months prior to presentation. Upon physical examination, epigastric discomfort and pallor were evident. The patient underwent gastrointestinal endoscopy with tissue biopsy at other medical center and the pathology suggested adenocarcinoma of the gastric antrum. Therefore, we read the results of the prior diagnostic report and proceeded to perform a subsequent Positron Emission Tomography/Computed Tomography (PET/CT). CT scans revealed enlarged lymph nodes in the lesser curvature of the stomach ( Figures 1A–D ). Subsequent PET/CT imaging unveiled thickening of the gastric antrum wall, displaying a concave configuration, heightened FDG uptake, and invasion of the plasma membrane surface. The tumor was located in the posterior wall, spanning from the antrum to the upper lesser curvature side of the stomach, measuring approximately 10 x 8 cm. The tumor presented with an ulcerated infiltrate and irregularities in the surrounding mucosa, involving the gastric serosa layer ( Figure 1E ). The preliminary diagnosis of gastric cancer was made by the combined examination results. The decision was made to employ a combination of Oxaliplatin and Tegafur chemotherapy as preoperative neoadjuvant therapy. After three cycles of neoadjuvant therapy, the patient demonstrated a reduction in the size of the primary tumor and lymph node shrinkage compared to the pre-treatment period. Then, the patient underwent radical gastrectomy for gastric cancer. However, the patient’s blood pressure continued to fluctuate during the operation, with readings consistently exceeding 140 mmHg, and reaching as high as 240 mmHg ( Figure 2 ). The tumor was situated in the posterior wall extending from the gastric antrum to the upper lesser curvature side of the gastric body. During the surgery, the upper margin showed positive results, leading to an extended resection. The upper margin of the upper part of the gastric body still remained positive. Ultimately, a total gastrectomy was performed, with negative margins both above and below the tumor. Simultaneous D2 lymph node dissection was conducted, and the pathological examination revealed 11 lymph nodes on the lesser curvature side of the stomach, with one showing tumor metastasis (1/11). On the greater curvature side, six lymph nodes were observed without tumor metastasis (0/6). No metastasis was detected in the lymph nodes of group 8 (0/2) or group 12 (0/2). Based on these findings, the pTNM staging was determined as pT2N1Mx. Histological examination showed that the nuclei of the tumor cells were round, with obvious nucleoli and clear cytoplasmic demarcation, and the Ki-67 proliferation index was 40%+. CK (AE1/AE3), CgA, and INSM1 staining were positive, while Syn and CD56 staining were negative ( Figures 3 A–F ). These collective findings ultimately led to the diagnosis of gastric paraganglioma. Three days post-surgery, a comprehensive evaluation of blood CAs and their metabolites was conducted. After tumor resection, the levels of norepinephrine (364 pg/ml, normal range 70-1700 pg/ml), epinephrine (22 pg/ml, normal range < 141 pg/ml), methoxy epinep hrine (27.3 pg/ml, normal range < 98 pg/ml), dopamine (14 pg/ml, normal range < 30 pg/ml), vanillylmandelic acid (6.79 ng/ml, normal range < 10.11 ng/ml), and homovanillic acid (10.43 ng/ml, normal range < 33.15 ng/ml) were within the normal range. However, methoxy norepinephrine (181.3 pg/ml, normal range < 164.9 pg/ml) remained persistently elevated. During a follow-up examination, it was observed that the patient’s CAs and their metabolites had returned to within the normal range. The levels of norepinephrine (161 pg/ml), epinephrine (30 pg/ml), methoxy epinephrine (22.6 pg/ml), dopamine (7 pg/ml), vanillic acid (2.76 ng/ml), homovanillic acid (6.7 ng/ml), and methoxy norepinephrine (56.4 pg/ml) were within normal limits. Such a return to baseline levels can be attributed to the effectiveness of the surgical intervention. Finally, the patient was successfully discharged from the hospital. The patient is well and without evidence of metastases 7 months after surgery.

Figure 1 (A, B) : Significant thickening of the gastric wall at the antrum was seen before neoadjuvant therapy. (C, D) : Significant reduction of visible primary foci and lymph nodes at the gastric antrum after neoadjuvant therapy. (E) : Macroscopic presentation of the resected stomach with extensive tumour invasion of the stomach.

Figure 2 Intraoperative blood pressure fluctuated, with most of the time it was located above 140 mmHg, reaching a maximum of 240 mmHg.

Figure 3 (A, B) : HE staining of the tumor showed diffuse growth of paraganglioma cells with moderately to poorly differentiated tubular adenocarcinoma. (C) : INSM1 immunohitochemistry shows strong positivity. (D) : AE1/AE3 immunohistochemistry shows strong positivity. (E) : CgA immunohistochemistry shows focal positivity. (F) : CD56 immunohistochemistry shows negativity.

3 Discussion

PGLs are now categorized as “metastatic” or “non-metastatic”, shifting away from the traditional benign versus malignant classification ( 10 ). Metastatic PGLs exhibit rapid progression and higher mortality rates than their non-metastatic counterparts ( 3 ). The evaluation of metastatic risk relies on factors such as tumor size, location, the presence of mutations, dopaminergic phenotype, and the Ki-67 index. Remarkably, clinical presentations of gastric PGLs may present with hypertension, palpitations, and diaphoresis. This highlights the concerning catecholamine hypersecretion frequently observed in PGLs, which can lead to life-threatening consequences. Plasma and urine tests for free CAs and their metabolites are crucial for diagnosing PGLs. Plasma free MNs are more sensitive in diagnosing PGLs compared to measuring CAs, as tumors continuously release metanephrines (MNs) into the bloodstream. Thus, measuring free MNs in plasma or 24-hour urine is the preferred diagnostic test for catecholamine overproduction.

While PGLs have been sporadically reported in various anatomical sites, gastric PGLs have been documented in only ten cases ( Table 1 ) ( 11 – 19 , 21 ). These included four male and six female patients with a mean age of 64 years. The tumors were predominantly located in the fundus of the stomach in three cases, while others were situated in the anterior gastric wall, posterior gastric wall, and lesser curvature of the stomach. Clinical presentations among the patients primarily included epigastric pain, abdominal mass, vomiting, diarrhea, and various gastrointestinal symptoms. The mean tumor size was approximately 6 cm, with a maximum recorded size of up to 15 cm. Surgical intervention constituted the primary treatment approach, with four patients exhibiting positivity for chromogranin A, neuron-specific enolase, and immunohistochemistry.

Table 1 Summary of cases with paragaglioma of stomach.

Genetic testing was performed and analyzed 680 tumor-related genes. We identified three genes associated with paragangliomas (MEN1, EPAS1, MDH2). Meanwhile, missense mutations in EPAS1 and MDH2 which associated with PGLs of the Tricarboxylic acid cycle and hypoxia signaling pathway, result in aberrant regulation and drive the development of paragangliomas ( 21 ). The conclusive diagnosis of paraganglioma relies on postoperative pathological examination. The presence of CgA and INSM1 characterizes neuroendocrine tumors, including PGLs. A Ki-67 positivity of 40% indicates higher proliferative activity and increased invasiveness. Differentiating between PGLs and gastrointestinal mesenchymal tumors is difficult due to their co-expression of SMA. However, negative CD117 and positive SMA results can help exclude GISTs as a diagnosis ( 2 ). The patient’s pathological examination showed Muc-5AC expression in gastric mucosal cells. Preoperative abdominal CT scan with contrast did not find any adrenal lesions. PET/CT scan results did not indicate the presence of metastatic tumors in the adrenal gland. Mixed gastric adenoendocrine carcinomas are diagnosed based on WHO criteria, with both adenoepithelial and neuroendocrine components comprising at least 30% of the tumor. Studies indicate at least two positive markers (CgA, Syn, CD56) in mixed adenoneuroendocrine carcinomas. In this case, the markedly elevated blood pressure during resection, in conjunction with postoperative immunohistochemistry favored the diagnosis of gastric paraganglioma. Surgical removal of the primary tumor significantly improves patient symptoms and overall survival ( 2 ). Meanwhile, Preoperative control of catecholamine levels is essential to reduce the risks associated with intraoperative blood pressure fluctuations.

The clinical presentation of PGLs varies significantly, making early recognition and appropriate treatment crucial to prevent complications and reduce mortality risk.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author.

Ethics statement

Written informed consent was obtained from the individual(s) for the publication of any potentially identifiable images or data included in this article.

Author contributions

CH: Writing – review & editing, Writing – original draft. BL: Writing – review & editing, Writing – original draft. BH: Writing – review & editing, Visualization, Resources. MZ: Data curation, Resources, Writing – review & editing. ZW: Data curation, Writing – review & editing. XZ: Resources, Writing – review & editing, Visualization. FL: Data curation, Writing – review & editing. YH: Data curation, Writing – review & editing. WG: Supervision, Resources, Project administration, Writing – review & editing, Data curation, Conceptualization.

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.

Acknowledgments

We thank all the authors who contributed to this topic.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Abbreviations

PGLs, paragangliomas; CAs, catecholamines; MNs, metanephrines; CT, computed tomography; SMA, smooth muscle actin; CgA, chromogranin A.

1. Mete O, Asa SL, Gill AJ, Kimura N, de Krijger RR, Tischler A. Overview of the 2022 WHO classification of paragangliomas and pheochromocytomas. Endocrine Pathology . (2022) 33:90–114. doi: 10.1007/s12022-022-09704-6

PubMed Abstract | CrossRef Full Text | Google Scholar

2. Young WF. Paragangliomas. Ann New York Acad Sci . (2006) 1073:21–9. doi: 10.1196/annals.1353.002

CrossRef Full Text | Google Scholar

3. Dahia PLM. Pheochromocytoma and paraganglioma pathogenesis: learning from genetic heterogeneity. Nat Rev Cancer . (2014) 14:108–19. doi: 10.1038/nrc3648

4. Nölting S, Bechmann N, Taieb D, Beuschlein F, Fassnacht M, Kroiss M, et al. Personalized management of pheochromocytoma and paraganglioma. Endocrine Rev . (2022) 43:199–239. doi: 10.1210/endrev/bnab019

5. Kawanabe S, Katabami T, Oshima R, Yanagisawa N, Sone M, Kimura N. A rare case of multiple paragangliomas in the head and neck, retroperitoneum and duodenum: A case report and review of the literature. Front Endocrinol . (2023) 13. doi: 10.3389/fendo.2022.1054468

6. Iwamoto G, Kawahara T, Tanabe M, Ninomiya S, Takamoto D, Mochizuki T, et al. Paraganglioma in the bladder: a case report. J Med Case Rep . (2017) 11:306. doi: 10.1186/s13256-017-1473-2

7. Sinkre P, Lindberg G, Albores-Saavedra J. Nasopharyngeal gangliocytic paraganglioma - A case report with emphasis on histogenesis. Arch Pathol Lab Med . (2001) 125:1098–100. doi: 10.5858/2001-125-1098-NGP

8. Yu L. Malignant paraganglioma of the rectum: The first case report and a review of the literature. World J Gastroenterol . (2013) 19:8151–5. doi: 10.3748/wjg.v19.i44.8151

9. Müller U, Troidl C, Niemann S. SDHC mutations in hereditary paraganglioma/pheochromocytoma. Familial Cancer . (2005) 4:9–12. doi: 10.1007/s10689-004-0621-1

10. Lam AKY. Update on adrenal tumours in 2017 world health organization (WHO) of endocrine tumours. Endocrine Pathology . (2017) 28:213–27. doi: 10.1007/s12022-017-9484-5

11. Tsygan VM, Khonelidze GB, Modonova NM, Zisman IF. [Malignant paraganglioma of the stomach (one case)]. Voprosy onkologii . (1969) 15:75–7.

PubMed Abstract | Google Scholar

12. Veselov VS. Chemodectoma of the stomach. Khirurgiia . (1970) 46:94–6.

13. Westbrook KC, Bridger WM, Williams GD. Malignant nonchromaffin paraganglioma of the stomach. Am J surgery . (1972) 124:407–9. doi: 10.1016/0002-9610(72)90052-9

14. Delamarre J, Potet F, Capron JP, Minh HN, Lorriaux A. Gastric chemodectoma: study of one case Archives francaises des maladies de l’appareil digestif. Arch Fr Mal App Dig. (1975) 64(4):339–46.

15. Crosbie J, Humphreys WG, Maxwell M, Maxwell P, Cameron CH, Toner PG. Gastric paraganglioma: an immunohistological and ultrastructural case study. J submicroscopic cytology pathology . (1990) 22:401–8.

Google Scholar

16. Schmid C, Beham A, Steindorfer P, Auböck L, Waltner F. Non-functional Malignant paraganglioma of the stomach. Virchows Archiv A Pathological Anat histopathology . (1990) 417:261–6. doi: 10.1007/BF01600143

17. Laforga JB, Vaquero M, Juanpere N. Paragastric paraganglioma: a case report with unusual alveolar pattern and myxoid component. Diagn Cytopathol . (2012) 40:815–9. doi: 10.1002/dc.21665

18. Bura R, Manca A, Ambu R, Pisano G, Melis A, Maturo A, et al. Gastric paraganglioma: case report and review of the literature. Il Giornale di chirurgia . (2017) 38:84–9. doi: 10.11138/gchir/2017.38.2.084

19. Vincenzo P, Francesca M, Maurizio R, Agata F, Antonio M, Eugenio C. Gastric paraganglioma: a case report and a review of the literature. Annali italiani di chirurgia . (2014) 85:1–6. ePub.

20. Sandroussi C, Ahmad H. Laparoscopic resection for a gastric pheochromocytoma: a rare presentation of an uncommon tumor. Surg laparoscopy endoscopy percutaneous techniques . (2009) 19:e95–7. doi: 10.1097/SLE.0b013e3181a2f8a6

21. Tella SH, Taïeb D, Pacak K. HIF-2alpha: Achilles’ heel of pseudohypoxic subtype paraganglioma and other related conditions. Eur J Cancer . (2017) 86:1–4. doi: 10.1016/j.ejca.2017.08.023

Keywords: gastric paraganglioma, diagnostic, immunohistochemistry, catecholamine crisis, case report

Citation: Hu C, Luo B, Hong B, Zhang M, Wu Z, Zhu X, Luan F, Huang Y and Gong W (2024) Gastric paraganglioma: a case report and review of literature. Front. Oncol. 14:1357612. doi: 10.3389/fonc.2024.1357612

Received: 18 December 2023; Accepted: 18 March 2024; Published: 02 April 2024.

Reviewed by:

Copyright © 2024 Hu, Luo, Hong, Zhang, Wu, Zhu, Luan, Huang and Gong. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Weihua Gong, [email protected]

† These authors have contributed equally to this work

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

• Case report
• Open access
• Published: 31 March 2024

Atypical lipoma of the right piriformis muscle: a case report and review of the literature

• Xiao Qiu 1 ,
• Xiaoyong Luo 1 &
• Renmei Wu 1  

Journal of Medical Case Reports volume  18 , Article number:  189 ( 2024 ) Cite this article

32 Accesses

1 Altmetric

Metrics details

Piriformis muscle mass is rare, which is particular for intrapiriformis lipoma. Thus far, only 11 cases of piriformis muscle mass have been reported in the English literature. Herein, we encountered one patient with intrapiriformis lipoma who was initially misdiagnosed.

Case presentation

The patient is a 50-year-old Chinese man. He complained of osphyalgia, right buttock pain, and radiating pain from the right buttock to the back of the right leg. Both ultrasound and magnetic resonance imaging demonstrated a cyst-like mass in the right piriformis muscle. Ultrasonography-guided aspiration was performed on this patient first, but failed. He was then recommended to undergo mass resection and neurolysis of sciatic nerve. Surprisingly, final histology revealed the diagnosis of intrapiriformis lipoma. The patient exhibited significant relief of symptoms 3 days post-surgery.

Diagnosis and differential diagnosis of radicular pain are potentially challenging but necessary. Atypical lipoma is prone to be misdiagnosed, especially in rare sites. It is notable for clinicians to be aware of the presence of intrapiriformis lipoma to avoid misdiagnosis and inappropriate treatment.

Peer Review reports

Piriformis syndrome (PS), also known as sciatic nerve outlet syndrome, caused by compression of the sciatic nerve by the piriformis muscle, is characterized by occasional sciatic-type pain, tingling, and numbness in the buttock along the sciatic nerve pathway down to the lower thigh and the calf [ 1 ]. The causes of PS are diversified, including inflammatory, traumatic, tumoral, and malformative factors [ 2 , 3 ]. PS triggered by space-occupying lesions of the piriformis muscle is very rare. Up to date, only 11 cases of piriformis muscle mass have been reported in the English literature [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ].

Lipomas are one of the most common mesenchymal neoplasms and can occur in any region of the body that contains fat component, including the subcutaneous soft tissues, mediastinum, retroperitoneum, bones, or along the gastrointestinal tract [ 11 ]. Intrapiriformis lipoma is rare and the diagnosis might be intractable when presenting atypical. In addition, misdiagnosis can lead to inappropriate treatment, which causes unsatisfactory outcomes. Here, we present a case of a large intrapiriformis lipoma that was initially misdiagnosed, highlighting that clinicians should be aware that intrapiriformis lipoma might harbor atypical manifestations upon examination.

A 50-year-old Chinese man presented to the orthopedics department with chief complaints of osphyalgia, right buttock pain, and radiating pain from the right buttock to the back of the right leg. The right buttock pain was the most prominent symptom. The pain was accelerated by movement and relieved by lying supine, which induced abnormal walk in the patient. No previous relevant treatment or surgery was reported. Additionally, there was no significant relevant family or social history.

Lasegue’s sign and its strengthening test were positive. Physical examination also demonstrated the positive findings of right femoral nerve traction test and Faber test, and the limitation of right hip abduction was observed. Neurological examination of the lower limb did not demonstrate any loss of sensation or reduced muscle power in any of the nerve root distributions. Non-remarkable finding was revealed after the abdominal examination.

As no apparent abnormalities were indicated upon the plain radiograph imaging of his lumbar spine, magnetic resonance imaging (MRI) scan of the lumbar/sacral area of the spine was then suggested, showing lumbar disc herniation (LDH), which did not account for the patient’s predominant right buttock pain. Thus, the musculoskeletal ultrasound (MSK-US) for the sciatic nerve scanning was performed, implying that the right sciatic nerve was pushed by an anechoic mass within the right piriformis muscle measuring 6 cm mediolateral, 2.3 cm anteroposterior, and 2.6 cm craniocaudal. The lobulated mass was cystic-like with regular margins and no posterior wall enhancement (Fig.  1 ). Subsequently, further MRI of the pelvis and ipsilateral hip indicated a cystic-like lesion in piriformis muscle region with low T1 signal and high T2 signal, and the maximum measurement was about 3.1 cm mediolateral and 2.2 cm anteroposterior (Fig.  2 ). Considering these results, a piriformis ganglion was suspected, and the differential diagnoses included hematoma, metastatic tumor, and so forth.

Sonographic examination showing a separate anechoic mass (white arrows) above the outlet of the right piriformis muscle pushing the right sciatic nerve (blue arrows). A Sagittal view(low- frequency probe); B Transverse view (high-frequency probe)

MRI demonstrating multiple cysts (arrows) in piriformis muscle region with long T1 ( A ) and long T2 ( B ) signals

Aiming to achieve the final diagnosis, the ultrasonography-guided aspiration was conducted, but failed due to unextracted cystic fluid. In addition, significant resistance was encountered when injecting with physiological saline. As for the undefined nature of the mass and the associated serious symptoms, malignancy could not be excluded; the patient was suggested to undergo piriformis muscle mass resection and neurolysis of sciatic nerve. Operative finding showed the compression of right sciatic nerve by a fat-like mass at the lower margin of piriformis muscle measuring 5 cm mediolateral, 2 cm anteroposterior, and 2 cm craniocaudal. Final histology revealed that the lesion was fibrous adipose tissue, which was consistent with diagnosis of lipoma (Fig.  3 ). The patient exhibited significant relief of symptoms 3 days post-surgery. No recurrence of relevant symptoms was observed during 24-month follow-up period.

Under microscope inspection, removed specimen revealed fibrous adipose tissue within the lesion, consistent with lipoma

Lower back pain can present with radicular pain caused by lumbosacral nerve root pathology. As a major cause of lower back pain, sciatica, and radicular leg pain, LDH is usually the first considered diagnosis. Similarly, in our case LDH was initially considered according to the MRI of the lumbar/sacral spine. However, the primary pain in the right buttock of this patient was unexplained on the diagnosis of LDH.

PS, also known as sciatic nerve outlet syndrome, is a type of sciatic neuralgia caused by compression of the piriformis muscle on the sciatic nerve. Typical manifestations include buttock pain and radiating pain in the innervated area of the sciatic nerve. In general, etiologies are composed of traumatic bleeding, adhesions, scars, anatomical variations, and so forth [ 2 ]. Of note, intrapiriformis lesion enlarging the muscle may be the common cause of sciatic nerve compression-induced secondary PS, whereas PS triggered by space-occupying lesions of the piriformis muscle is very rare. To the best of our knowledge, only 11 cases have been reported in the literature thus far; these patients and our present case are summarized in Table  1 [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ], among which only 1 case of intramuscular lipomas occurring within the piriformis muscle leading to secondary PS have been previously reported in the literature [ 6 ].

Lipomas can be classified into superficial and deep lesions according to the location. Deep-seated lipomas are less common than superficial lipomas, which may be located under the muscle (submuscular), within the muscle (intramuscular), between the muscles (intermuscular), or on top of the muscle (supramuscular) [ 11 ]. Clinically, lipomas often present as asymptomatic slow-growing mass or swelling with no palpable mass. The application of ultrasound (US) in the examination of lipomas is very frequent. Usually, superficial lipomas might manifest as a hyperechoic solid mass without posterior acoustic enhancement or show as a isoechoic mass on gray-scale US. Compared with superficial lipomas, the deep-seated type can present as various US characteristics. In addition, few reports in the literature show the hypoechoic, isoechoic, or anechoic properties of deep ones [ 12 , 13 , 14 ]. However, the intrapiriformis lipoma in our case was featured as an anechoic lesion, usually indicated as cystic lesions. The MRI of the pelvis and ipsilateral hip showed the same signal characteristics as those of water on all sequences. Therefore, the lesion within piriformis muscle region was then misdiagnosed as ganglion and distinguished from neuschwannoma, liposarcoma, hematoma, lymphoma, metastatic tumor, and so on. Therefore, ultrasonography-guided aspiration was performed while noncystic fluid was extracted.

The echogenicity of lipomas may range from hyperechoic to anechoic, depending on the component percentage of connective tissue and other reflective interfaces presented within a lipoma [ 15 ]. It has been postulated that US and MRI appearance of lipomas are largely dependent on the internal cellularity, specifically on the proportion of fat and water within the lesion [ 16 ]. When the proportion of water in the lipoma is high, it may present the same imaging characteristics as this case.

Generally, intrapiriformis lipoma does not require treatment in the absence of symptoms, while for our case, considering the serious symptoms of this patient and undefined nature, even including malignancy, after series of examinations, surgical treatment was recommended. Fortunately, the patient showed significant relief of symptoms 3 days after surgery. No recurrence of associated symptoms was observed during 24-month follow-up period.

Despite the potentially significant challenges for the diagnosis and differential diagnosis of radicular pain, it is highly necessary and essential. It is notable that medical practitioners should be aware of this condition and exclude space-occupying lesions of piriformis muscles when encountering patients presenting with radicular pain. Our case highlighted the atypical manifestations of lipomas in rare areas such as piriformis muscles, for which condition-adequate examinations should be performed and surgery might be finally suggested to reach the final diagnosis, thus avoiding misdiagnosis and inappropriate treatment and increasing the life quality of these patients.

Availability of data and materials

The authors of this manuscript are willing to provide additional information regarding the case report.

Abbreviations

Musculoskeletal ultrasound

Magnetic resonance imaging

Piriformis syndrome

Lumbar disc herniation

Hopayian K, Song F, Riera R, Sambandan S. The clinical features of the piriformis syndrome: a systematic review. Eur Spine J. 2010;19:2095–109.

Article   PubMed   PubMed Central   Google Scholar  

Kirschner JS, Foye PM, Cole JL. Piriformis syndrome, diagnosis and treatment. Muscle Nerve. 2009;40(1):10–8.

Article   PubMed   Google Scholar  

Byrd JWT. Piriformis syndrome. Oper Tech Sports Med. 2005;13(1):71–9.

Article   Google Scholar  

Salar O, Flockton H, Singh R, Reynolds J. Piriformis muscle metastasis from a rectal polyp. Case Rep. 2012. https://doi.org/10.1136/bcr-2012-007208 .

Domínguez-Páez M, De Miguel-Pueyo LS, Medina-Imbroda JM, González-García L, Moreno-Ramírez V, Martín-Gallego A, et al . Sciatica secondary to extrapelvic endometriosis affecting the piriformis muscle. Case report. Neurocirugia (Astur). 2012;23(4):170–4.

Drampalos E, Sadiq M, Thompson T, Lomax A, Paul A. Intrapiriformis lipoma: an unusual cause of piriformis syndrome. Eur Spine J. 2015;24:551–4.

Park JH, Jeong HJ, Shin HK, Park SJ, Lee JH, Kim E. Piriformis ganglion: an uncommon cause of sciatica. Orthop Traumatol Surg Res. 2016;102(2):257–60.

Article   CAS   PubMed   Google Scholar  

Lodin J, Brušáková Š, Kachlík D, Sameš M, Humhej I. Acute piriformis syndrome mimicking cauda equina syndrome: illustrative case. J Neurosurg Case Lessons. 2021;2(17): CASE21252.

Sanuki N, Kodama S, Seta H, Sakai M, Watanabe H. Radiation therapy for malignant lumbosacral plexopathy: a case series. Cureus. 2022;14(1): e20939.

PubMed   PubMed Central   Google Scholar  

Ward TRW, Garala K, Dos Remedios I, Lim J. Piriformis syndrome as a result of intramuscular haematoma mimicking cauda equina effectively treated with piriformis tendon release. BMJ Case Reports CP. 2022;15(3): e247988.

Paunipagar BK, Griffith J, Rasalkar DD, Chow LTC, Kumta SM, Ahuja A. Ultrasound features of deep-seated lipomas. Insights Imaging. 2010;1(3):149–53.

Goldberg BB. Ultrasonic evaluation of superficial masses. J Clin Ultrasound. 1975;3(2):91–4.

Rahmani G, McCarthy P, Bergin D. The diagnostic accuracy of ultrasonography for soft tissue lipomas: a systematic review. Acta radiologica open. 2017;6(6):2058460117716704.

Fujioka K. A comparison between superficial and deep-seated lipomas on high-resolution ultrasonography: with RTE and MRI appearances. Biomed J Sci Tech Res. 2019;19:14220–4.

Google Scholar  

Behan M, Kazam E. The echographic characteristics of fatty tissues and tumors. Radiology. 1978;129(1):143–51.

Inampudi P, Jacobson JA, Fessell DP, Carlos RC, Patel SV, Delaney-Sathy LO, et al . Soft-tissue lipomas: accuracy of sonography in diagnosis with pathologic correlation. Radiology. 2004;233(3):763–7.

Download references

Acknowledgements

The author(s) gratefully acknowledge the useful suggestions given by Dr Ji-Bin Liu of Thomas Jefferson University, and the author(s) thank Xiaobo Luo for providing language assistance during article writing.

Not applicable.

Author information

Authors and affiliations.

Department of Ultrasound, Suining Central Hospital, 127 Desheng West Road, Suining, Sichuan, China

Xiao Qiu, Xiaoyong Luo & Renmei Wu

You can also search for this author in PubMed   Google Scholar

Contributions

Renmei Wu contributed to the collection of the medical history data. Xiao Qiu contributed to the manuscript preparation of this case report. Xiaoyong Luo supervised the case report.

Corresponding author

Correspondence to Renmei Wu .

Ethics declarations

Ethics approval and consent to participate.

The study protocol was approved by the ethics review board of Suining Central Hospital (no. LLSLH20220011).

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interests

The author(s) declared no potential conflicts of interest regarding the publication of this manuscript.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Qiu, X., Luo, X. & Wu, R. Atypical lipoma of the right piriformis muscle: a case report and review of the literature. J Med Case Reports 18 , 189 (2024). https://doi.org/10.1186/s13256-024-04507-1

Download citation

Received : 04 April 2022

Accepted : 13 March 2024

Published : 31 March 2024

DOI : https://doi.org/10.1186/s13256-024-04507-1

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Piriformis muscle

Journal of Medical Case Reports

ISSN: 1752-1947

• Submission enquiries: Access here and click Contact Us
• General enquiries: [email protected]

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• Can Med Educ J
• v.12(3); 2021 Jun

Writing, reading, and critiquing reviews

Écrire, lire et revue critique, douglas archibald.

1 University of Ottawa, Ontario, Canada;

Maria Athina Martimianakis

2 University of Toronto, Ontario, Canada

Why reviews matter

What do all authors of the CMEJ have in common? For that matter what do all health professions education scholars have in common? We all engage with literature. When you have an idea or question the first thing you do is find out what has been published on the topic of interest. Literature reviews are foundational to any study. They describe what is known about given topic and lead us to identify a knowledge gap to study. All reviews require authors to be able accurately summarize, synthesize, interpret and even critique the research literature. 1 , 2 In fact, for this editorial we have had to review the literature on reviews . Knowledge and evidence are expanding in our field of health professions education at an ever increasing rate and so to help keep pace, well written reviews are essential. Though reviews may be difficult to write, they will always be read. In this editorial we survey the various forms review articles can take. As well we want to provide authors and reviewers at CMEJ with some guidance and resources to be able write and/or review a review article.

What are the types of reviews conducted in Health Professions Education?

Health professions education attracts scholars from across disciplines and professions. For this reason, there are numerous ways to conduct reviews and it is important to familiarize oneself with these different forms to be able to effectively situate your work and write a compelling rationale for choosing your review methodology. 1 , 2 To do this, authors must contend with an ever-increasing lexicon of review type articles. In 2009 Grant and colleagues conducted a typology of reviews to aid readers makes sense of the different review types, listing fourteen different ways of conducting reviews, not all of which are mutually exclusive. 3 Interestingly, in their typology they did not include narrative reviews which are often used by authors in health professions education. In Table 1 , we offer a short description of three common types of review articles submitted to CMEJ.

Three common types of review articles submitted to CMEJ

More recently, authors such as Greenhalgh 4 have drawn attention to the perceived hierarchy of systematic reviews over scoping and narrative reviews. Like Greenhalgh, 4 we argue that systematic reviews are not to be seen as the gold standard of all reviews. Instead, it is important to align the method of review to what the authors hope to achieve, and pursue the review rigorously, according to the tenets of the chosen review type. Sometimes it is helpful to read part of the literature on your topic before deciding on a methodology for organizing and assessing its usefulness. Importantly, whether you are conducting a review or reading reviews, appreciating the differences between different types of reviews can also help you weigh the author’s interpretation of their findings.

In the next section we summarize some general tips for conducting successful reviews.

How to write and review a review article

In 2016 David Cook wrote an editorial for Medical Education on tips for a great review article. 13 These tips are excellent suggestions for all types of articles you are considering to submit to the CMEJ. First, start with a clear question: focused or more general depending on the type of review you are conducting. Systematic reviews tend to address very focused questions often summarizing the evidence of your topic. Other types of reviews tend to have broader questions and are more exploratory in nature.

Following your question, choose an approach and plan your methods to match your question…just like you would for a research study. Fortunately, there are guidelines for many types of reviews. As Cook points out the most important consideration is to be sure that the methods you follow lead to a defensible answer to your review question. To help you prepare for a defensible answer there are many guides available. For systematic reviews consult PRISMA guidelines ; 13 for scoping reviews PRISMA-ScR ; 14 and SANRA 15 for narrative reviews. It is also important to explain to readers why you have chosen to conduct a review. You may be introducing a new way for addressing an old problem, drawing links across literatures, filling in gaps in our knowledge about a phenomenon or educational practice. Cook refers to this as setting the stage. Linking back to the literature is important. In systematic reviews for example, you must be clear in explaining how your review builds on existing literature and previous reviews. This is your opportunity to be critical. What are the gaps and limitations of previous reviews? So, how will your systematic review resolve the shortcomings of previous work? In other types of reviews, such as narrative reviews, its less about filling a specific knowledge gap, and more about generating new research topic areas, exposing blind spots in our thinking, or making creative new links across issues. Whatever, type of review paper you are working on, the next steps are ones that can be applied to any scholarly writing. Be clear and offer insight. What is your main message? A review is more than just listing studies or referencing literature on your topic. Lead your readers to a convincing message. Provide commentary and interpretation for the studies in your review that will help you to inform your conclusions. For systematic reviews, Cook’s final tip is most likely the most important– report completely. You need to explain all your methods and report enough detail that readers can verify the main findings of each study you review. The most common reasons CMEJ reviewers recommend to decline a review article is because authors do not follow these last tips. In these instances authors do not provide the readers with enough detail to substantiate their interpretations or the message is not clear. Our recommendation for writing a great review is to ensure you have followed the previous tips and to have colleagues read over your paper to ensure you have provided a clear, detailed description and interpretation.

Finally, we leave you with some resources to guide your review writing. 3 , 7 , 8 , 10 , 11 , 16 , 17 We look forward to seeing your future work. One thing is certain, a better appreciation of what different reviews provide to the field will contribute to more purposeful exploration of the literature and better manuscript writing in general.

In this issue we present many interesting and worthwhile papers, two of which are, in fact, reviews.

Major Contributions

A chance for reform: the environmental impact of travel for general surgery residency interviews by Fung et al. 18 estimated the CO 2 emissions associated with traveling for residency position interviews. Due to the high emissions levels (mean 1.82 tonnes per applicant), they called for the consideration of alternative options such as videoconference interviews.

Understanding community family medicine preceptors’ involvement in educational scholarship: perceptions, influencing factors and promising areas for action by Ward and team 19 identified barriers, enablers, and opportunities to grow educational scholarship at community-based teaching sites. They discovered a growing interest in educational scholarship among community-based family medicine preceptors and hope the identification of successful processes will be beneficial for other community-based Family Medicine preceptors.

Exploring the global impact of the COVID-19 pandemic on medical education: an international cross-sectional study of medical learners by Allison Brown and team 20 studied the impact of COVID-19 on medical learners around the world. There were different concerns depending on the levels of training, such as residents’ concerns with career timeline compared to trainees’ concerns with the quality of learning. Overall, the learners negatively perceived the disruption at all levels and geographic regions.

The impact of local health professions education grants: is it worth the investment? by Susan Humphrey-Murto and co-authors 21 considered factors that lead to the publication of studies supported by local medical education grants. They identified several factors associated with publication success, including previous oral or poster presentations. They hope their results will be valuable for Canadian centres with local grant programs.

Exploring the impact of the COVID-19 pandemic on medical learner wellness: a needs assessment for the development of learner wellness interventions by Stephana Cherak and team 22 studied learner-wellness in various training environments disrupted by the pandemic. They reported a negative impact on learner wellness at all stages of training. Their results can benefit the development of future wellness interventions.

Program directors’ reflections on national policy change in medical education: insights on decision-making, accreditation, and the CanMEDS framework by Dore, Bogie, et al. 23 invited program directors to reflect on the introduction of the CanMEDS framework into Canadian postgraduate medical education programs. Their survey revealed that while program directors (PDs) recognized the necessity of the accreditation process, they did not feel they had a voice when the change occurred. The authors concluded that collaborations with PDs would lead to more successful outcomes.

Experiential learning, collaboration and reflection: key ingredients in longitudinal faculty development by Laura Farrell and team 24 stressed several elements for effective longitudinal faculty development (LFD) initiatives. They found that participants benefited from a supportive and collaborative environment while trying to learn a new skill or concept.

Brief Reports

The effect of COVID-19 on medical students’ education and wellbeing: a cross-sectional survey by Stephanie Thibaudeau and team 25 assessed the impact of COVID-19 on medical students. They reported an overall perceived negative impact, including increased depressive symptoms, increased anxiety, and reduced quality of education.

In Do PGY-1 residents in Emergency Medicine have enough experiences in resuscitations and other clinical procedures to meet the requirements of a Competence by Design curriculum? Meshkat and co-authors 26 recorded the number of adult medical resuscitations and clinical procedures completed by PGY1 Fellow of the Royal College of Physicians in Emergency Medicine residents to compare them to the Competence by Design requirements. Their study underscored the importance of monitoring collection against pre-set targets. They concluded that residency program curricula should be regularly reviewed to allow for adequate clinical experiences.

Rehearsal simulation for antenatal consults by Anita Cheng and team 27 studied whether rehearsal simulation for antenatal consults helped residents prepare for difficult conversations with parents expecting complications with their baby before birth. They found that while rehearsal simulation improved residents’ confidence and communication techniques, it did not prepare them for unexpected parent responses.

Review Papers and Meta-Analyses

Peer support programs in the fields of medicine and nursing: a systematic search and narrative review by Haykal and co-authors 28 described and evaluated peer support programs in the medical field published in the literature. They found numerous diverse programs and concluded that including a variety of delivery methods to meet the needs of all participants is a key aspect for future peer-support initiatives.

Towards competency-based medical education in addictions psychiatry: a systematic review by Bahji et al. 6 identified addiction interventions to build competency for psychiatry residents and fellows. They found that current psychiatry entrustable professional activities need to be better identified and evaluated to ensure sustained competence in addictions.

Six ways to get a grip on leveraging the expertise of Instructional Design and Technology professionals by Chen and Kleinheksel 29 provided ways to improve technology implementation by clarifying the role that Instructional Design and Technology professionals can play in technology initiatives and technology-enhanced learning. They concluded that a strong collaboration is to the benefit of both the learners and their future patients.

In his article, Seven ways to get a grip on running a successful promotions process, 30 Simon Field provided guidelines for maximizing opportunities for successful promotion experiences. His seven tips included creating a rubric for both self-assessment of likeliness of success and adjudication by the committee.

Six ways to get a grip on your first health education leadership role by Stasiuk and Scott 31 provided tips for considering a health education leadership position. They advised readers to be intentional and methodical in accepting or rejecting positions.

Re-examining the value proposition for Competency-Based Medical Education by Dagnone and team 32 described the excitement and controversy surrounding the implementation of competency-based medical education (CBME) by Canadian postgraduate training programs. They proposed observing which elements of CBME had a positive impact on various outcomes.

You Should Try This

In their work, Interprofessional culinary education workshops at the University of Saskatchewan, Lieffers et al. 33 described the implementation of interprofessional culinary education workshops that were designed to provide health professions students with an experiential and cooperative learning experience while learning about important topics in nutrition. They reported an enthusiastic response and cooperation among students from different health professional programs.

In their article, Physiotherapist-led musculoskeletal education: an innovative approach to teach medical students musculoskeletal assessment techniques, Boulila and team 34 described the implementation of physiotherapist-led workshops, whether the workshops increased medical students’ musculoskeletal knowledge, and if they increased confidence in assessment techniques.

Instagram as a virtual art display for medical students by Karly Pippitt and team 35 used social media as a platform for showcasing artwork done by first-year medical students. They described this shift to online learning due to COVID-19. Using Instagram was cost-saving and widely accessible. They intend to continue with both online and in-person displays in the future.

Adapting clinical skills volunteer patient recruitment and retention during COVID-19 by Nazerali-Maitland et al. 36 proposed a SLIM-COVID framework as a solution to the problem of dwindling volunteer patients due to COVID-19. Their framework is intended to provide actionable solutions to recruit and engage volunteers in a challenging environment.

In Quick Response codes for virtual learner evaluation of teaching and attendance monitoring, Roxana Mo and co-authors 37 used Quick Response (QR) codes to monitor attendance and obtain evaluations for virtual teaching sessions. They found QR codes valuable for quick and simple feedback that could be used for many educational applications.

In Creation and implementation of the Ottawa Handbook of Emergency Medicine Kaitlin Endres and team 38 described the creation of a handbook they made as an academic resource for medical students as they shift to clerkship. It includes relevant content encountered in Emergency Medicine. While they intended it for medical students, they also see its value for nurses, paramedics, and other medical professionals.

Commentary and Opinions

The alarming situation of medical student mental health by D’Eon and team 39 appealed to medical education leaders to respond to the high numbers of mental health concerns among medical students. They urged leaders to address the underlying problems, such as the excessive demands of the curriculum.

In the shadows: medical student clinical observerships and career exploration in the face of COVID-19 by Law and co-authors 40 offered potential solutions to replace in-person shadowing that has been disrupted due to the COVID-19 pandemic. They hope the alternatives such as virtual shadowing will close the gap in learning caused by the pandemic.

Letters to the Editor

Canadian Federation of Medical Students' response to “ The alarming situation of medical student mental health” King et al. 41 on behalf of the Canadian Federation of Medical Students (CFMS) responded to the commentary by D’Eon and team 39 on medical students' mental health. King called upon the medical education community to join the CFMS in its commitment to improving medical student wellbeing.

Re: “Development of a medical education podcast in obstetrics and gynecology” 42 was written by Kirubarajan in response to the article by Development of a medical education podcast in obstetrics and gynecology by Black and team. 43 Kirubarajan applauded the development of the podcast to meet a need in medical education, and suggested potential future topics such as interventions to prevent learner burnout.

Response to “First year medical student experiences with a clinical skills seminar emphasizing sexual and gender minority population complexity” by Kumar and Hassan 44 acknowledged the previously published article by Biro et al. 45 that explored limitations in medical training for the LGBTQ2S community. However, Kumar and Hassen advocated for further progress and reform for medical training to address the health requirements for sexual and gender minorities.

In her letter, Journey to the unknown: road closed!, 46 Rosemary Pawliuk responded to the article, Journey into the unknown: considering the international medical graduate perspective on the road to Canadian residency during the COVID-19 pandemic, by Gutman et al. 47 Pawliuk agreed that international medical students (IMGs) do not have adequate formal representation when it comes to residency training decisions. Therefore, Pawliuk challenged health organizations to make changes to give a voice in decision-making to the organizations representing IMGs.

In Connections, 48 Sara Guzman created a digital painting to portray her approach to learning. Her image of a hand touching a neuron showed her desire to physically see and touch an active neuron in order to further understand the brain and its connections.