Peer review
Peer review is the evaluation of scholarly work by other experts before, during, or after publication.
What peer review is
Peer review is a process in which people with relevant expertise evaluate scholarly work. In journal publishing, reviewers usually read a manuscript, assess its methods, evidence, originality, clarity, and contribution, then send comments to an editor. The editor uses those reports, along with their own judgment, to decide what happens next.
How journal review works
A manuscript is submitted to a journal, screened by an editor, and sent to reviewers if it fits the journal and looks reviewable. Reviewers may recommend acceptance, revision, rejection, or more analysis. Authors often revise the work in response. The final decision belongs to the editor, not to any single reviewer.
What reviewers look for
Reviewers may check whether the research question is clear, methods are appropriate, data support the claims, previous work is cited fairly, limitations are acknowledged, and ethical standards are met. They may also ask whether the work is important enough for a particular journal's audience.
Models of review
In single-anonymous review, reviewers know the authors but authors do not know the reviewers. In double-anonymous review, both sides are masked as much as possible. In open peer review, identities, reports, or exchanges may be public. Post-publication review happens after a paper, preprint, dataset, or report is already visible.
Beyond journals
Peer review is also used for grant proposals, conference papers, books, standards, data papers, and some government or institutional research processes. Funding agencies use expert review to compare applications and judge significance, feasibility, investigators, methods, and likely impact.
Limits and failure modes
Peer review can miss errors, fraud, weak statistics, hidden conflicts, unshared data, or overconfident conclusions. It can also be slow, inconsistent, biased, or dependent on unpaid labor. Reviewers are experts, but they usually see only what authors and editors provide.
Peer review and preprints
A preprint is usually shared before journal peer review is complete. That does not make it useless, but it changes how readers should interpret it. Public comments, journal review, replication, data checks, and later corrections can all shape what the research community eventually accepts.
Why it matters
Peer review is one of the main quality-control systems in scholarly communication. It matters because research influences medicine, policy, technology, education, and public trust. The process is imperfect, but thoughtful review can improve work before it becomes part of the scientific record.