It is tempting to think of peer review as a gate: a manuscript is scrutinised, it passes, it is published, and the matter is closed. But publication is not the end of scrutiny — or it should not be. Errors slip through review, problems become visible only once a paper is read widely, and occasionally misconduct is detected only after the work is in the literature. A scholarly record that could never be questioned after publication would accumulate its mistakes forever. Post-publication peer review is the practice of continuing to scrutinise work after it appears, and it has become an essential part of how the literature corrects itself. This article examines that practice and the people and platforms behind it, drawing on the research integrity domain of the CASRAI Dictionary.
What post-publication peer review is
Post-publication peer review is exactly what its name suggests: the evaluation of a published work by the community after it has appeared, rather than only by selected reviewers before it appears. It can take many forms — a published commentary, a letter to the editor, a structured review on a dedicated platform, or an informal note on social media. What unites them is the recognition that the few reviewers who assessed a paper before publication are not the last word on it, and that the wider community of readers can identify problems the original reviewers could not. It treats the published paper not as a closed case but as a claim that remains open to examination.
PubPeer and the online commentary layer
The best-known infrastructure for post-publication review is PubPeer, an online platform that allows readers to comment on published papers, identified by their DOI or other identifier. PubPeer functions as a kind of comment layer over the literature: a place where someone who notices a problem — an apparently duplicated image, an implausible statistic, a method that does not add up — can post their observation for others to see and discuss, often anonymously. Anonymity is a deliberate and important feature, because raising concerns about published work, particularly the work of senior or powerful researchers, can carry real professional risk. PubPeer has become a significant venue where concerns about specific papers are aired, examined and, in many cases, ultimately acted upon by journals and institutions. It has made post-publication scrutiny visible and persistent in a way that scattered private worries never were.
Research sleuths
Alongside the platforms is a community of individuals who have become known as research sleuths or integrity investigators: people who systematically examine the published literature for signs of error or misconduct. Some focus on image integrity, developing a practised eye for duplicated, manipulated or reused figures; others look for statistical impossibilities, tortured phrasing characteristic of manipulated text, or patterns suggesting paper-mill production. Their work is often painstaking, frequently voluntary, and sometimes carried out at personal cost. These sleuths have been responsible for surfacing a substantial number of serious problems that formal pre-publication review missed, and their findings — often posted on platforms like PubPeer — have triggered investigations, corrections and retractions. They represent a distributed, motivated form of scrutiny that complements the formal systems, catching things those systems were never designed to catch.
From concern to correction
Raising a concern is only the beginning; the question is what happens next. The journey from an observation to a formal change in the record typically runs through several stages:
- A concern is raised — on a platform such as PubPeer, in a letter to the journal, or directly to an institution.
- The journal or institution investigates. Editors may issue an expression of concern to flag that a paper is under question while inquiries proceed.
- A correction is made where the problem is genuine but limited — a corrigendum that fixes the specific error.
- A retraction is issued where the problems are serious enough to undermine the work’s reliability, formally signalling that the findings should not be relied upon.
These mechanisms are how the published record is actually changed, and they are the formal counterpart to the informal scrutiny that surfaces the problems in the first place.
The role of COPE
The handling of these situations is not improvised; it is guided by established norms. The Committee on Publication Ethics (COPE) provides guidance to editors and publishers on how to respond to concerns about published work — how to investigate fairly, when an expression of concern is appropriate, how to handle corrections, and the proper grounds and process for retraction. This guidance matters because post-publication scrutiny, for all its value, must be handled responsibly: authors are entitled to due process, a concern is not the same as a proven fault, and the record must be changed carefully and transparently rather than reactively. COPE’s frameworks give editors a principled basis for turning a raised concern into a fair and proportionate response.
Self-correction as a feature, not a failure
It is worth stating plainly: a retraction or correction is not a sign that science is broken. It is a sign that the self-correcting mechanism is working. The alternative — a literature in which flawed work, once published, can never be challenged or corrected — would be far worse. Post-publication peer review, the platforms that host it, the sleuths who drive much of it, and the editorial processes that turn its findings into formal action are together the visible machinery of a scholarly record that takes its own reliability seriously. The willingness to revisit and correct published work is one of the things that distinguishes a healthy research culture from a complacent one.
Describing integrity work consistently
For concerns, investigations, corrections and retractions to be handled and recorded consistently across journals and institutions, the terms involved must mean the same thing everywhere — what counts as an expression of concern, a correction or a retraction, and how each is recorded. That consistency is what the CASRAI Dictionary supports: a shared vocabulary so that the status of a published work is understood identically wherever it appears, which underpins sound research administration. And because scrutiny after publication is itself genuine scholarly contribution, the work of reviewing and correcting can be described in the same framework used for every other — the CRediT taxonomy and its full set of contribution roles. The scholarly record is trustworthy not because it is never wrong, but because it has robust ways of putting itself right.