How to Write a Peer Review: A Practical Guide for Researchers
Reviewing papers is one of the most underrated career moves in academic science. It's how you learn what editors look for, build relationships with journals before you submit your own work, and understand why good papers get rejected. Most PIs start reviewing in their postdoc years. Some PhD students start in year 3 or 4 with their supervisor's guidance. This guide covers the mechanics of writing a good review, the ethics involved, and what not to do.
Sources are cited in the references section below.
Why Review, and When to Start
Peer review isn't charity work. It's a strategic career activity with tangible returns.
Learn what makes papers succeed
Reading 10-20 manuscripts a year, including the ones that don't work, teaches you more about scientific writing than any course. You'll start seeing patterns in what gets rejected and what gets through.
Build editorial relationships
Editors track reviewer quality. A reliable reviewer who delivers thoughtful, on-time reviews gets remembered. When you submit your own papers, that reputation matters.
Join journal reviewer lists
Your name enters the journal's reviewer database. This is searchable by editors across the publisher's portfolio. One good review for a Nature journal can lead to invitations from other Nature titles.
Be seen as a contributor
Reviewing shows you're engaged in the field beyond your own publications. Search committees and grant reviewers notice peer review activity on CVs under Professional Service.
When to start and how much to take on
- • Most journals start inviting postdocs to review once they have 2–3 first-author publications in the relevant area
- • PhD students can review with explicit permission from their PI. This is ethical and common as long as the PI supervises and takes responsibility
- • A thorough review takes 4–8 hours for a typical original research article, less for shorter papers or follow-on revisions
- • 2–5 reviews per year is a reasonable load for a postdoc; more than 8–10/year starts affecting your own work
Getting Invited to Review
Most junior researchers wait for invitations to appear in their inbox. That works eventually, but there are faster paths.
Build a publication record first
You need at least 1-2 papers in the area before journals will invite you. Editors search for reviewers by matching manuscript keywords to author publication records. No publications in the topic area means you won't appear in those searches.
Register on Publons (Web of Science reviewer recognition)
Create a profile and note your expertise areas. Some editors search Publons directly when they can't find reviewers through the usual channels. It also gives you a verified record of your review activity for your CV.
Submit your own papers
When you submit to a journal, editors see your email domain, research area, and recent publications. You'll start getting invitations naturally from journals you've submitted to, even if your paper was rejected.
Email a section editor directly
If you want to review for a specific journal, write to the managing editor or a section editor. Introduce yourself, list your expertise and recent publications. Keep it to 3 sentences. Many journals accept reviewer self-nominations.
Ask your mentor to suggest you
Your PhD supervisor or postdoc mentor can directly suggest you as a reviewer when they decline an invitation. This is how most junior researchers get their first review invitations, and it carries the mentor's implicit endorsement.
The Structure of a Peer Review
Most journals use a structured submission form with text boxes, but always write the narrative review in a document first, then paste in. This gives you a record and lets you edit before submitting.
1. Summary paragraph (3-5 sentences)
Restate the paper's central claim and what the authors did to support it. This proves you read it carefully and helps the editor understand whether your concerns are fundamental or minor. Don't evaluate the paper here. Just show you understood it.
2. Major concerns (numbered)
Issues that must be addressed for the paper to be publishable. These are problems with the science itself: missing controls, unwarranted conclusions, statistical errors, missing comparison to prior work, insufficient sample size, or methodology that doesn't support the claims. Each concern should be specific and actionable.
3. Minor concerns (numbered)
Presentation issues, unclear figures, citation gaps, or language corrections that don't affect the scientific conclusions. These are things the authors can fix without new experiments or major rewriting.
4. Recommendation
Major revision, minor revision, or reject. Be honest and match your recommendation to your concerns. If you listed five major concerns that each require new experiments, don't recommend minor revision. If your only concerns are about figure clarity and one missing citation, don't recommend major revision.
What NOT to include
- • A list of typos. That's copy-editing, not peer review
- • Complaints about writing quality without specific examples
- • Vague comments like "the conclusions are not supported" without explaining why
Length: a useful review is typically 400–800 words. Longer is not better. Every comment should be actionable.
Major vs. Minor: Getting the Calibration Right
This is where junior reviewers mess up most often. They call everything “major,” or they bury a fatal issue inside the minor comments. Editors are reading your review partly to judge whether you know the difference.
Usually major
- • The main claim depends on a control that is missing or inadequate
- • The statistics do not support the central conclusion
- • The paper overclaims beyond what the data can actually show
- • A key comparison to prior literature is missing and changes the novelty story
- • The methods are too unclear to assess reproducibility
- • A requested experiment would genuinely decide whether the conclusion is true
Usually minor
- • Figure labels are unclear or abbreviations are undefined
- • One or two citations are missing
- • The discussion needs tightening but the science is sound
- • A schematic model would improve readability
- • The methods need small clarifications, not a redesign
- • Language is awkward in places but understandable
Confidential Comments to the Editor
Many systems give you a separate box for comments to the editor. Most of the time, you do not need to say anything there that you would not say to the authors. But there are a few situations where that box matters.
What that box is not for
It is not a place to say one thing to the editor and a softer version to the authors. Editors notice that immediately. If your public comments say “promising paper, minor concerns” and your confidential note says “reject,” you look untrustworthy. Use the confidential box for context, not for a second hidden review.
Writing Comments That Are Actually Useful
The difference between a review that helps authors improve their paper and one that frustrates everyone comes down to specificity.
Good review comments
- +"The authors should validate the finding in an independent dataset" — specific and actionable
- +Include citations when you know relevant prior work the authors missed. Say what was published, don't just say "this has been done"
- +Frame concerns as questions when appropriate: "It's unclear whether the effect persists in the absence of X — have the authors tested this?"
- +If you think a paper should be rejected, say so clearly with the specific reason
- +When you disagree with a method, acknowledge whether it's a preference vs. a scientific problem
Unhelpful review comments
- -"Validation is needed" — vague, doesn't say what kind or why
- -"This has been published before" without citing what was published
- -"The methods are inadequate" without specifying which methods or what's wrong
- -Writing a detailed 3-page review of a paper you think is fundamentally flawed instead of recommending rejection with a clear reason
- -Sarcastic or condescending tone that editors will flag as unprofessional
Tone matters. Your comments will be read by the authors (anonymously) and by the editor. Both audiences matter. Professional, clear, and constructive beats clever or cutting.
Common Reviewer Mistakes
Ethics and Conflicts of Interest
Peer review runs on trust. The manuscript you receive is not public, and the review process imposes specific ethical obligations.
Confidentiality
The manuscript is not public. Don't share it, don't discuss it with colleagues (unless your journal explicitly allows collaborative reviews), and don't use ideas or data from it before the paper is published. Violating confidentiality is one of the most serious ethical breaches in peer review.
Conflicts requiring recusal
- • You have a paper competing with this one under review or in preparation
- • You've recently collaborated with one of the authors (typically within the last 3 years)
- • You have a financial interest in the outcome
- • You have a significant personal conflict with an author
When in doubt, disclose
Email the handling editor and describe the potential conflict. They'll decide whether you can still review. If you must decline, do it promptly (within 3–5 days) and suggest an alternative reviewer if you can.
Using AI to assist with peer reviews
Check the journal's policy before using any AI tools. Many journals (Nature, Cell, NEJM) prohibit using AI tools to write reviews because the manuscript is confidential and cannot be shared with third-party systems. This is an evolving area. Always check the specific journal's current policy before uploading any manuscript content to an AI system.
Reviewer Recognition
Peer review has historically been invisible work. That's changing. Several platforms now let you document and get credit for your reviews.
Publons (Web of Science Reviewer Recognition)
The main platform for recording and verifying peer review contributions. Most major publishers (Wiley, Springer Nature, Elsevier, Taylor & Francis) integrate with it. Reviews are tracked and can be made public, showing you reviewed for a journal, not what you said. It's free and links to your Web of Science author profile.
ORCID reviewer record
Some journals and publishers link review activity directly to your ORCID profile. This shows up on your ORCID page alongside your publications and is visible to anyone who looks at your profile.
Journal acknowledgments
Many journals send annual "thank you" emails or list top reviewers in their January issue. These appear in PubMed and are citable on your CV. Some journals (e.g., eLife, EMBO Journal) have moved toward publishing reviews alongside papers, giving reviewers public credit.
Listing reviews on your CV
Add reviewing activity under Professional Service: "Peer reviewer for Nature Medicine, Cell Metabolism, JCI (2022–present)". You don't need to list every review. Just the journals. If you reviewed 5+ papers for one journal in a year, you can note the volume (e.g., "12 reviews for Journal of Immunology, 2024–2025").
Frequently Asked Questions
Can PhD students write peer reviews?
Yes, with their PI's knowledge and involvement. It's ethically acceptable and professionally valuable for PhD students to review manuscripts, provided their supervisor is aware, takes responsibility for the review, and ideally gives feedback before submission. Some journals have formal policies on this, so check before you start.
How long should a peer review be?
400 to 800 words is typical for a full original research article. The goal is a clear summary, numbered major concerns, numbered minor concerns, and a recommendation. Longer reviews aren't more useful. Every comment should be actionable. A three-page review full of vague concerns is less helpful than a focused 400-word review with specific, addressable points.
What should I do if I suspect fraud or data fabrication in a paper I'm reviewing?
Contact the editor directly and confidentially. Do not include your concern in the review comments visible to authors. Describe specifically what you observed (duplicate figures, implausible statistics, inconsistent data). The editor will handle it from there. COPE (the Committee on Publication Ethics) has published flowcharts for how editors should respond to suspected fraud.
References
- Committee on Publication Ethics (COPE). Ethical Guidelines for Peer Reviewers. 2017. Retrieved March 2026. [publicationethics.org ↗]
- Publons / Web of Science. Reviewer Recognition. Retrieved March 2026. [publons.com ↗]
- Nature Portfolio. Peer Review Policies. Retrieved March 2026. [nature.com ↗]
- Ware M. Peer review: recent experience and future directions. New Journal of Physics. 2011;13(1):083002. [doi:10.1088/1367-2630/13/8/083002 ↗]
Suggested Citation
APA
Manusights. (2026). How to write a peer review: A practical guide for researchers. Retrieved from https://manusights.com/resources/how-to-peer-review
MLA
Manusights. "How to Write a Peer Review: A Practical Guide for Researchers." Manusights, 2026, manusights.com/resources/how-to-peer-review.
VANCOUVER
Manusights. How to write a peer review: a practical guide for researchers [Internet]. 2026. Available from: https://manusights.com/resources/how-to-peer-review
CC BY 4.0 - share and adapt freely with attribution to Manusights (manusights.com/resources).
Related guides in this collection