The Peer-Reviewed Process: How It Works, Who Reviews and Its Limits

Peer review is the critical assessment of a manuscript submitted to a journal by experts, and the journal’s editor, not the reviewers, makes the final decision. In practice the process runs from submission through editor screening and reviewer selection to reviewer reports, an editorial decision and notification of everyone involved. Reviewers are typically not paid by journals, and the best available evidence on whether the system improves research quality is limited rather than conclusive.

Short answer: what the peer-reviewed process is and is not

The ICMJE Recommendations, which many biomedical journals follow, define peer review as the critical assessment of manuscripts submitted to journals by experts who are not part of the editorial staff. Three consequences follow from that wording and from the rest of the ICMJE section on the submission and peer-review process. First, the unit that is reviewed is the submitted manuscript, not the journal as a brand. Second, reviewers advise and editors decide: journals are under no obligation to follow reviewer recommendations, favourable or negative. Third, peer review is a confidential process with defined duties for reviewers, editors and authors.

What the label does not tell you is how many reviewers saw a paper, whether they were anonymous to the authors, or how rigorous the check was. Those details are set by each journal’s own policy. The sections below describe the process as publishers and indexers document it, and the data table at the end of the page sets out who is expected to do what.

How the peer-review process works step by step

The steps below combine what the ICMJE Recommendations say about the roles of editors and reviewers with what Elsevier describes on its own peer review page. Other publishers vary in detail, so a journal’s guide for authors remains the authoritative description of its own workflow.

1. Submission. Authors submit a manuscript to a journal. ICMJE expects journals to treat the manuscript and its contents as confidential while it is under review.
2. Editorial handling. A handling editor reviews the submission. According to Elsevier, the handling editor selects and invites the reviewers.
3. Reviewer assessment. Invited reviewers assess the manuscript. ICMJE says reviewers are expected to respond promptly, to keep the manuscript strictly confidential and to declare relationships and activities that might bias their evaluation.
4. Editorial decision. The editor weighs the reports and decides. ICMJE is explicit that the editor is not bound by reviewer recommendations.
5. Notification. Elsevier states that most of its journals keep reviewers informed of the editorial decision and of the other reviewers’ recommendations. Reviewers should not keep copies of manuscripts after the review.

Elsevier also notes that whether a reviewer’s identity is visible to the author depends on the journal’s review model, which is set out in the journal’s guide for authors. For a comparison of those models, see single-blind vs double-blind vs open peer review.

Who actually does the peer review?

Peer review is done by external experts selected by the journal’s editors, not by the journal’s staff. ICMJE describes reviewers as experts, and Elsevier says its handling editor selects and invites them. Reviewers are therefore usually researchers working in the same or an adjacent field as the manuscript, acting on the editor’s invitation.

ICMJE attaches several duties to the role. Reviewers should keep the manuscript and the information in it strictly confidential, declare relationships and activities that might bias their evaluation, and respond promptly. They should not retain manuscripts after review. Journals, for their part, should acknowledge the contribution of peer reviewers. The editor remains the accountable decision maker. Practical guidance for someone invited to review is in how to conduct a peer review.

How to do a peer review of a research paper

A reviewer starts by accepting only if they can respond promptly and have no undeclared conflict, because those are the expectations ICMJE sets out. They then read the manuscript in confidence, assess it critically and report to the editor, who makes the decision. The detailed method, including how to structure a report, is covered in the CASRAI guide linked above. Elsevier points reviewers to its Researcher Academy for reviewer training.

What counts as a peer-reviewed source?

A peer-reviewed source is a manuscript that a journal assessed through its peer-review process before publication. Because the unit of review is the manuscript, being published in a journal that uses peer review does not by itself prove that every item in the issue was reviewed; the journal’s own policy states which article types go through external review. The Directory of Open Access Journals (DOAJ) is a useful contrast: its application guide states that all articles must pass through a quality control system (peer review) before publication, and for arts and humanities journals it accepts editorial review by two editors in place of external reviewers.

To check one specific article, follow the steps in how to know if an article is peer reviewed. For how a peer-reviewed article differs from a preprint, see preprints vs peer-reviewed articles.

What an indexer requires of the process: the DOAJ example

Journal indexes publish criteria that describe a minimum process. DOAJ’s application guide, read on 2026-11-14, requires that every article passes a peer-review quality control system. It requires at least two independent reviewers per article, with the exception noted above for arts and humanities. It requires the process to be described publicly on the journal’s website. It also requires an editorial board of at least five editors, named with their affiliations, and it caps endogeny: no more than 25% of papers in the latest two issues may come from editors, board members or reviewers. DOAJ recommends that articles show their submitted, accepted and published dates, and that reviewers and editors do not use generative AI to produce their assessments. These are DOAJ’s published requirements for inclusion, not a general statement about all journals.

Are reviewers paid for their work?

Journal reviewers are generally not paid by the journal. The ICMJE Recommendations say journals should acknowledge the contribution of peer reviewers and do not address compensation. Funder review is different: panels that assess grant applications can pay honoraria. CASRAI’s news analysis Will paying reviewers ease the peer review crisis? covers a journal, Advances in Psychology, that has paid a fee per review since 2022, and the NIH proposal discussed there. Whether a given journal pays is stated, if at all, in that journal’s own reviewer guidance.

Why is peer review important?

Publishers present peer review as the mechanism that places expert scrutiny between a submission and publication. Elsevier’s peer review page quotes a figure that 82% of researchers agreed that without peer review there is no control in scientific communication; that is Elsevier’s own statement, and the page does not give the survey detail behind it. The practical value for readers is a filter: a reviewed article has at least passed an expert assessment under a stated policy, which the previous sections show how to inspect. For a short definition, see the dictionary entry for peer review.

What are the downsides of peer review?

The most rigorous evidence review of the question is a Cochrane methodology review, Jefferson and colleagues’ Editorial peer review for improving the quality of reports of biomedical studies (MR000016.pub3). It included 28 studies and concluded that little empirical evidence is available to support the use of editorial peer review as a mechanism to ensure the quality of biomedical research. The authors also note that studying peer review is methodologically difficult, and that absence of evidence is not evidence of absence. Specific findings include:

• Concealing reviewer and author identities: no clear effect across 9 studies.
• Checklists: some evidence of benefit, from 2 studies.
• Reviewer training: no evidence of benefit, from 1 study.
• Peer review seemed to improve readability and the quality of reporting, from 2 studies with limited generalisability.

Read precisely, this is a finding about the quality of the evidence on biomedical editorial peer review, not proof that the system does not work. Other documented limits come from the process itself: ICMJE states that editors are free to disregard reviewer advice, so outcomes depend on editorial judgment, and reviewers must declare relationships that might bias their evaluation, which acknowledges that bias is a recognised risk.

Frequently asked questions

What is peer review in research?

It is the critical assessment of manuscripts submitted to journals by experts, followed by an editorial decision. The reviewers advise; the editor decides.

What counts as a peer-reviewed source?

A journal article that passed through the journal’s peer-review process before publication. Check the journal’s own policy for which article types are reviewed, and use the verification steps in the CASRAI guide linked above.

Who actually does the peer review?

External experts invited by the journal’s handling editor, working under ICMJE-style duties of confidentiality, prompt response and declared conflicts.

Are reviewers paid for their work?

Journals generally do not pay reviewers; ICMJE only says journals should acknowledge their contribution. Some exceptions and funder-panel honoraria are discussed in CASRAI’s news analysis.

How to do a peer review of a research paper?

Respond promptly, declare conflicts, keep the manuscript confidential, assess it critically and report to the editor. See the full guide linked above.

What are the downsides of peer review?

A Cochrane methodology review found little empirical evidence that editorial peer review ensures the quality of biomedical research, with uncertain evidence on blinding and reviewer training. The finding concerns the evidence base, not a proof of failure.

Why is peer review important?

It places expert assessment between submission and publication, and indexers such as DOAJ make it a condition of inclusion.

Sources

• ICMJE, Recommendations: Responsibilities in the Submission and Peer-Review Process, icmje.org, read 2026-11-14.
• Elsevier, Peer review for reviewers, elsevier.com, read 2026-11-14.
• DOAJ, Application guide, doaj.org, read 2026-11-14.
• Jefferson T et al., Editorial peer review for improving the quality of reports of biomedical studies, Cochrane Database of Systematic Reviews, MR000016.pub3, cochranelibrary.com, read 2026-11-14.