Peer review is the quiet engine of academic publishing: before a paper reaches readers, independent experts check whether its question matters, its methods hold up, and its conclusions follow from its evidence. Most researchers first meet peer review as authors, waiting anxiously for comments on their own work. But becoming a peer reviewer yourself is one of the fastest ways to improve your own writing, because it teaches you to read manuscripts the way editors and reviewers do — critically, structurally, and with an eye for what is missing.
This guide explains how to become a peer reviewer, how to handle your first invitation, and how to write a report that editors value. It is about the reviewer side of the process. If you are on the receiving end of comments, our guide on how to respond to peer reviewer comments covers that side, and our guide on double-blind peer review explained describes the review model used by journals such as GJVAS.
A reviewer is not a proofreader, and not a second author. Your job is to advise the editor, not to decide the paper's fate yourself. The editor makes the decision; your report is expert input into it. A good report answers three questions: is the research question important and original, are the methods sound enough to support the conclusions, and is the manuscript clear enough for its intended readers? Everything else — detailed comments, suggestions, corrections — serves those three questions.
Reviewers are usually unpaid volunteers, and the work is confidential. You must not discuss the manuscript, share it, or use its ideas before publication. That confidentiality is the foundation of trust in the system: authors submit unfinished work to journals on the understanding that reviewers will treat it as private. Journals also expect reviewers to declare conflicts of interest — for example, if you are collaborating with the authors, competing with them directly, or have a financial interest in the outcome — and to decline the review if a conflict prevents a fair judgement.
Editors find reviewers in a few reliable ways, and you can make yourself findable in each of them. The most common route is publication: when you publish papers in a field, editors searching for experts in that topic will find your name. A second route is recommendation: supervisors, co-authors, and colleagues suggest names to editors, so telling your supervisor or senior colleagues that you are willing to review is genuinely useful. A third route is the journal's own reviewer database, which many journals let researchers join by registering their interests and keywords.
Practical steps help. Keep your institutional profile and your ORCID record up to date with your research interests and publications, so an editor searching by keyword can find you. Make sure your email address is current wherever your papers are listed, because invitations sent to a dead address simply go elsewhere. And when you publish, consider adding a short note to the editor thanking them and mentioning your willingness to review in your area — editors remember willing, reliable reviewers, because finding them is one of the hardest parts of running a journal.
Early-career researchers are often surprised to learn that they do not need decades of experience to start. Editors regularly invite doctoral students and postdoctoral researchers, especially as co-reviewers alongside a supervisor, or for papers closely matching their recent work. If you are invited before you feel ready, it is acceptable to ask a supervisor to co-review with you, provided the journal allows it and the supervisor agrees — but you must tell the editor, because the review must remain confidential to the people the editor has approved.
When an invitation arrives, first check three things before accepting: the topic fits your expertise, you have no conflict of interest, and you can meet the deadline. Editors set deadlines, commonly a few weeks, and a late review can delay the whole process. If any of the three fails, decline promptly and, where you can, suggest another suitable reviewer. A fast, honest decline helps the editor far more than a slow, reluctant acceptance.
Once you accept, read the manuscript in two passes. On the first pass, read it as a reader: what is the question, what was done, what was found, and what is claimed? Note your overall impression before getting lost in detail. On the second pass, read critically section by section: does the introduction establish a real gap, do the methods match the question, do the results support the conclusions, and are the limitations acknowledged? Our guides on writing a methodology section and writing results and discussion sections describe the standards reviewers apply to those sections, and reading them will sharpen your own reviewing.
Take notes as you read, separating major issues from minor ones. Major issues affect the paper's validity or its main claims: a flawed design, an analysis that does not match the question, a conclusion the data cannot support, or missing ethical approval. Minor issues are matters of clarity, wording, formatting, or missing references. Keeping the two lists separate matters, because the editor needs to know whether the paper needs rethinking or merely tidying.
Most journals ask for two parts: confidential comments to the editor, and comments to the authors. The confidential section is where you give your overall recommendation — accept, minor revision, major revision, or reject — with a short justification. Be direct here: editors value a clear recommendation backed by reasons, not a long list of minor points with no conclusion. The comments to the authors are where the detailed feedback goes, and they should be written so that the authors can act on them.
Start the author comments with a brief summary of the paper in your own words, which shows the editor and the authors that you understood the work. Then list major comments first, numbered, each stating the problem, why it matters, and what would fix it. Follow with minor comments, also numbered and specific — page or line references help the authors find each point. Close with a short overall note: what is strong about the paper, and what would most improve it. Even a report recommending rejection should be courteous and specific; authors remember harsh, vague reviews far longer than critical, fair ones.
Tone matters as much as content. Reviewers sometimes write as if they are cross-examining the authors, but the purpose is improvement, not punishment. Criticise the work, not the people who did it, and avoid sarcasm, personal remarks, or demands that the authors cite your own papers unless genuinely relevant. If you recommend that the authors cite a specific work, explain why it matters to their argument; unexplained self-citation requests are one of the behaviours editors watch for.
Confidentiality comes first: do not share the manuscript, discuss it with colleagues who are not approved reviewers, or use its ideas in your own work before publication. If you need a colleague's opinion on a technical point, ask the editor's permission first. Second, declare conflicts honestly and decline when you cannot be fair. Third, do not delay: if you cannot complete the review, tell the editor early so a replacement can be found. Fourth, be alert to possible misconduct — duplicated text, manipulated images, or missing ethics approval — and raise it privately with the editor rather than accusing the authors directly. The Committee on Publication Ethics publishes guidance for reviewers that editors expect you to know, and reading it before your first review is time well spent.
Reviewing also benefits you directly. It keeps you current in your field, it shows you what editors accept and reject and why, and it is recognised service that belongs on an academic CV. Some journals and reviewer-recognition services let you record verified reviews, which can support promotion or funding applications. But the deepest benefit is to your own writing: after reviewing ten papers, you will spot the weaknesses in your own manuscripts far earlier, because you have practised seeing them in other people's work. Our guide on how to publish a research paper places review in the full publication process, and our guide on research ethics, consent, and animal welfare covers the ethical standards behind many review decisions.
The most common mistake is reviewing the paper you wish the authors had written, rather than the paper they wrote. A study with a modest aim, done well, is better than an ambitious study done badly, and reviewers should judge the work against its own question, not against their own research agenda. The second mistake is focusing only on minor errors — grammar, formatting, reference style — while missing a major flaw in the design or analysis. The third is the opposite: listing major objections without explaining what would fix them, which leaves authors guessing. The fourth is delay: accepting a review and then letting the deadline pass silently, which holds up the authors' work and damages your standing with the editor. A short, honest, on-time review beats a long, late one every time.
The core of reviewing stays the same whatever the manuscript type — question, methods, evidence, clarity — but the emphasis shifts, and a good reviewer adjusts to it. For an original research paper, the methods and the match between results and conclusions carry the most weight: a flawed design or an analysis that cannot support the claim matters more than any number of minor wording issues. Read the methods as if you had to repeat the study, and check that every result reported in the paper is backed by an analysis described in the methods section.
For a review article, the judgement changes. Here you are assessing coverage and balance rather than a single study's design: does the review address a defined question, is the literature search described transparently, are important studies missing, and does the synthesis fairly represent disagreements in the field? A review that cites only studies supporting one view, or that omits a major strand of the literature, has a structural problem even if its prose is polished. For a case report, the standards shift again: novelty and documentation matter most, so check whether the case genuinely teaches something new, whether the clinical detail is complete enough for another clinician to learn from, and whether the discussion stays within what a single case can claim.
Whatever the type, keep your report proportionate to the manuscript in front of you. A short case report does not need a review as long as the paper itself, and a complex trial deserves more than a paragraph of general praise. Match the depth of your comments to the depth of the work, focus on the issues that would change the editor's decision, and leave minor points — wording, formatting, reference style — clearly marked as minor, so the authors can prioritise the revisions that matter.
| Stage | What you do | What the editor needs |
|---|---|---|
| Invitation | Check expertise, conflicts, deadline | A fast accept or decline |
| First read | Grasp the question, methods, findings, claims | Your overall impression |
| Critical read | Test methods, results, conclusions, ethics | Major vs minor issues, separated |
| Report | Summary, numbered comments, recommendation | A clear, reasoned recommendation |
| After submission | Keep the manuscript confidential | No discussion or use before publication |
These authoritative external resources explain the standards and guidance mentioned in this article:
Do I need a PhD to become a peer reviewer?
No. Editors invite reviewers based on expertise in the paper's topic, which early-career researchers often have from recent research. Doctoral students commonly review, sometimes as co-reviewers with a supervisor, where the journal allows it.
How long does a review take?
Most reviewers spend a few hours spread over several days: a first read, a critical second read, and time to write the report. Journals usually allow a few weeks, and the deadline is stated in the invitation — check it before accepting.
What if I find the paper is outside my expertise?
Decline promptly and suggest a colleague who fits better, if you can. Editors would far rather have a fast decline than a review from someone guessing outside their field.
Can I use ideas from a manuscript I reviewed?
No. Manuscripts under review are confidential, and their ideas must not be used, shared, or discussed until the paper is published. If you need a colleague's view on a technical point, ask the editor's permission first.
Should I recommend accept or reject, or only comment?
Most journals ask for both: comments to the authors, and a confidential recommendation to the editor. Give a clear recommendation with reasons — editors value decisiveness backed by evidence.
Is reviewing worth the time?
Yes, for most researchers. It keeps you current, teaches you editorial standards that improve your own writing, and counts as recognised academic service. Recording verified reviews can also support promotion and funding applications.