How to Be a Great Peer Reviewer : ACG Case Reports Journal

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How to Be a Great Peer Reviewer

Sempokuya, Tomoki MD1; McDonald, Nicholas MD2; Bilal, Mohammad MD2

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ACG Case Reports Journal 9(12):p e00932, December 2022. | DOI: 10.14309/crj.0000000000000932
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Peer review is a critical part of the publication process of a scientific journal to control quality of publication.1 The primary purpose of peer review is to guide the decision regarding publication and whether the manuscript needs improvement prior to publication.2 As peer review requires complex and critical analytical skills,2 it may be intimidating for early career researchers or clinicians to perform peer review for a journal, despite the interest. There are several benefits of becoming a reviewer for a journal, whether it is the hope to gain experience with the publication process, learn how to improve your manuscripts, improve your knowledge base of the topic to improve patient care, enhance your curriculum vitae, or obtain continuing medical education credits. In addition, you also help shape a journal; your opinion helps editors decide whether to offer acceptance, revision, or rejection. You will be able to see diverse manuscripts from authors with different perspectives and potentially expose yourself to new topics that may inspire your future work. This editorial aims to educate researchers and clinicians on becoming excellent peer reviewers to increase our journal's pool of potential peer reviewers.


Journal websites, including ACG Case Reports Journal often have a link to register as a peer reviewer. You can register as a peer reviewer for ACG Case Reports Journal by creating an account in Editorial Manager, the Journal's submission system. If you submit your manuscript to the Journal and fill out your expertise on the submission site, editors may use the information in the future to send an invitation to be a peer reviewer. Since many journals actively seek peer reviewers, you can contact the journal's editorial office about your interest. Alternatively, you may ask mentors about pairing up with them on their assigned peer reviews with appropriate supervision.


Accepting the peer review invitation

To provide a high-quality peer review, you must dedicate the appropriate amount of time to the task since the peer review process is a responsibility that has a significant impact.2 The reviewers must complete their peer review on time as delayed submission can negatively affect the journal's publication time, which is often used as a benchmark. Editors will be in a serious dilemma if the reviewer submits their review late since they will be unclear on when they'll have the necessary information to provide the author with a decision.3

It is critical to provide a high-quality peer review to be a frequent peer reviewer. Many journals have a rating system to assess peer review quality. If you provide a peer review which is not comprehensive, editors may not invite you to be a peer reviewer again. In general, for your first peer review for a case report, you should spend at least a few hours reviewing the manuscript, getting familiar with the topic area, and then reviewing the manuscript again to provide feedback and recommendations. As you gain peer review experience and become familiar with the process, the time needed to perform reviews decreases.

Editors are often seeking an expert opinion regarding the manuscript. Therefore, you must know the topic well before you accept to review. For example, experts know that a particular liver condition that appears rare at one hospital may not be so rare at the tertiary liver transplant center. Unfortunately, it is impossible to know the details of rare conditions often presented in a case reports journal. As such, expert knowledge can be aided by an appropriate literature review, including reviewing the reference list. The goal is to learn enough to provide an expert opinion after spending some time reading the content area. Lastly, it is critical to maintain confidentiality.2

Reading the manuscript

While reading a manuscript, we suggest taking notes in a separate document. We recommend not using the journal's reviewer page for the comments, as websites can timeout and you risk losing your content before submission of the review.

The initial evaluation should focus on the overall flow, linguistics, and quality assessment.4 Additionally, the title should reflect the content and central message of the manuscript. When doing a literature search, many people screen the studies by title before reading the abstract. Therefore, the reviewer should assess the appropriateness and accuracy of the title. The abstract should contain the current knowledge related to the case and unknown content related to the topic. It would be helpful to see the manuscript's learning point or core message. It is critical to ensure that the content of the title and abstract are consistent.4

The introduction should not be a list of literature reviews. This section should reflect pertinent and accurate background information related to the topic and how this manuscript will add new knowledge to the current literature. As editors, we would appreciate it if the reviewers did a literature search and provided the related essential studies with the comments.

The case should be concise and appropriate for the scope of the journal. Reviewers should ensure the accuracy of the diagnosis with pertinent positives and negatives and the appropriateness of the treatment. If the authors utilized a novel method, a comparison to the standard of care should be made. The case should include appropriate, high-quality images such as radiographic, endoscopic, or pathology images.

The discussion should lead to the main learning point of the manuscript. The authors' arguments should support the conclusion by providing an appropriate literature review of the content and highlighting its uniqueness. Appropriate disclosure of the manuscript's limitations and the topic's future direction should be listed.

Lastly, reviewers should check each reference closely to ensure the authors cited important and relevant studies.4 When authors cite their previous studies in the current manuscript, it is considered self-citation. Reviewers should ensure that self-citations are appropriately employed.

General comments to the authors

Peer review should be comprehensive, succinct, and accurate, and comment on the importance, novelty, and impact of the study.1,5 It is helpful to give constructive feedback to their colleagues since respectful comments are the key to a good peer review. Reviewers can also be considered consultants; recommendations should be taken seriously, which authors may not agree with.5 Authors spend a fair amount of time writing a manuscript, so we discourage degrading comments.

The first sentences of the review should summarize the manuscript and show the clinical significance.1 The subsequent sentences should point out the main learning points of the manuscript and explain how this manuscript can be improved. Lastly, the suitability and relevance of the manuscript should be evaluated.4

The reviewer should avoid including the comments regarding the decision for publication. Often, a journal has limited space for publication, and editors sometimes make a difficult decision to reject the manuscript, even if it is well-written. You should include your recommendation in the confidential comments to the editors and provide rationale for the recommended decision. Editors rely heavily on your expertise; knowing what you are thinking and your rationale is essential. Lastly, reviewers should attempt to minimize bias while reviewing the manuscript.2

Major and minor points

Major points describe suggested changes that require considerable effort for revision.4 The reviewers should state the manuscript's strengths and weaknesses in bullet points with the supporting statement for the argument and relevant literature for supporting evidence. Reviewers should ensure the accuracy of the data presented.2

Minor points should address nonfatal errors such as grammatical or linguistic errors or ambiguous statements. If reviewers have questions regarding figures or tables, they can mention them here. If the reviewers find a helpful reference article, they may suggest authors cite the relevant studies.

Confidential comments to editors

If the reviewer has a concern about the quality of the manuscript or ethical concerns, reviewers can address their concerns here. This section is usually confidential and will not be shared with the authors. It is also helpful for the editors to see a summary of the manuscript with the suggested revisions to the authors. It is important to note that the International Committee of Medical Journal Editors states that reviewers can only recommend the decision to the editors, and the final decision is the sole responsibility of the editors.6


Knowing when to decline a peer review invitation is critical, even if you are an expert in the field. Here are several examples:

  1. Conflicts of interest
  2. Collaborator of the study
  3. Personal knowledge of the study
  4. Same institution
  5. Lack of knowledge about the topic

There is limited information for peer reviewers to know how to review a manuscript, especially a case report. As such, peer review quality varies significantly and sometimes makes it hard for editors to decide after the peer review. This editorial provided a step-by-step process for reviewers to provide high-quality peer reviews. While getting started with the peer review process can seem intimidating, with these simple steps, you can become an excellent peer reviewer and enjoy some of the benefits of being a reviewer. In the future, ACG Case Reports Journal may benefit from creating a feedback mechanism and mentorship program for reviewers to improve our overall peer review quality.2

Please refer to bibliography if you are interested in further reading on this topic.7,8

You can also listen to our podcast on peer review with Clinical and Translational Gastroenterology Editor-in-Chief Brian Jacobson at and on most music streaming services.


1. Pawlak KM, Grover SC, Drenth JPH, Onken JE, Siau K. How to train the next generation to provide high-quality peer-reviews. Clin Gastroenterol Hepatol. 2022;20(9):1902–6.
2. Mayden KD. Peer review: Publication's gold standard. J Adv Pract Oncol. 2012;3(2):117–22.
3. McPeek M, Shaw R, DeAngelis D, et al. The golden rule of reviewing. Am Naturalist. 2009;173(5):E155–8.
4. Siau K, Kulkarni AV, El-Omar E. How to be a good reviewer for a scientific journal. J Clin Exp Hepatol. 2022;12(4):1238–43.
5. Weinstein R. How to write a manuscript for peer review. J Clin Apher. 2020;35(4):358–66.
6. Misra DP, Ravindran V. Peer review in academic publishing: Threats and challenges. J R Coll Physicians Edinb. 2019;49(2):99–100.
7. Jefferson T, Rudin M, Brodney Folse S, Davidoff F. Editorial peer review for improving the quality of reports of biomedical studies. Cochrane Database Syst Rev. 2007;2007(2):MR000016.
8. Lippi G. How do I peer-review a scientific article? A personal perspective. Ann Transl Med. 2018;6(3):68.
© 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.