Frequently asked questions

Commenting guidelines
> What publications can be discussed? Any publication.
> What classes of comments can I make? Major, minor, negative or positive.
> What can my comment contain? Facts, logic and publicly verifiable information.
> What tone should I adopt? Polite and neutral.
> How to write a high-quality comment? Specificity, analysis, support and context.
> Do authors receive alerts? Yes.
> Can I post external links? Please do.
> How does moderation work?
> Why doesn't PubPeer review comments scientifically?
> How can I ensure anonymity? Use Tor.
> Why can’t I find the paper I want to comment on?
> Do you block specific commenters or comments about specific authors?

> My paper has been commented! What can I do?
> Did someone just accuse me of fraud?
> Is someone out to get me?
> Who did this to me?
> Why does PubPeer allow comments that I know are wrong?
> I answered, so can you make the comment disappear?
> The whole world can read this forever?
> How can I convince ungracious commenters?
> Can I claim a copyright violation?
> Why did PubPeer send me a nasty email? (We didn’t.)

User accounts
> I lost my anonymous access code. Can I recover it?
> Can I choose my own pseudonym?
> Why hasn’t my comment appeared?
> Can I get an account without a suitable publication?

PubPeer Integration
> What are the browser plugins?
> What is the Zotero plugin?
> How does Twitter integration work and what is the PubPeerBot?

> Can I access PubPeer data?

PubPeer Foundation and site
> Who runs this site?

Terms of service
> What are the terms of use?
> What is your privacy policy?

Commenting guidelines

What publications can be discussed? Any publication.

We encourage discussion and commenting about all publications in all fields. The only requirement is for the publication to have an ID that we recognize. Such IDs include the DOI and IDs for PubMed and the ArXiv. Note that failure of searches for DOIs often reflect problems with indexing by the journal or CrossRef.

What classes of comments can I make? Major, minor, negative or positive.

PubPeer accepts all types of comments about papers. Although many comments concern issues that are central to a paper’s conclusions, this is not an obligation. Comments about minor issues and details should be interpreted as such, although attention to detail is often important in science. We may draw the line at issues that have no significant bearing on the science, its interpretation or its presentation.

What can my comment contain? Facts, logic and publicly verifiable information.

By far the most important rule for commenting is to base your statements on publicly verifiable information. This will usually be the data published in the paper you are commenting on, but could also be another paper or some other source such as a book, newspaper or website. If possible, please include supporting information in the comment and you must at least cite your sources. This is to allow easy verification of the quality of the comment (see also the FAQ “How to write a high-quality comment?”). Conversely, comments based upon hearsay are unacceptable---you can’t say, "My friend used to work in the lab and said their glassware is dirty". Unfortunately, this rule means that PubPeer is not particularly suitable for whistleblowers whose comments are based upon personal knowledge. Reports of personal knowledge, which must be made using a signed account and supported as strongly as possible, will be moderated on a case by case basis.

Observation of the “publicly verifiable information” rule automatically focuses discussion on the facts and the science. It also reduces the legal risks to PubPeer and maybe to you. We carry legal risk for you. To defend defamation cases we may have to prove the truth of your statements. Please make it easy for us to evaluate the legal risk of your comment, by carefully supporting your statements and logic, ideally within the comment itself. When you write, imagine having to defend the truth of your statement in court. However, our aim is not just to have a strong defense, but never to need one, since defending any case costs money and we certainly don’t have an unlimited supply. If you can’t afford to defend yourself, you lose. If your comment only contains the obvious truth, that should discourage unhappy authors from initiating any legal attack.

Allegations of misconduct are forbidden on PubPeer. They are anyway unnecessary. Your audience on the site is mostly composed of highly intelligent researchers and scientists. They are quite capable of drawing their own conclusions if the facts are clearly presented.

You should also avoid personal comments about authors and speculation about researcher actions and motives. This is non-scientific, but also can pose legal problems.

What tone should I adopt? Polite and neutral.

Although we understand that frustration can easily build up, unnecessarily strong language just makes you and the site appear unreasonable, reducing the effectiveness of your comment and handing people a pretext to ignore your comment specifically and the site generally. Remember---your readers understand.

How to write a high-quality comment? Specificity, analysis, support and context.

We only accept high-quality comments that will be useful to other readers. Below we attempt to codify or at least explain current policy, which has evolved over time and may continue to do so.

Please proof-read your comment carefully before posting it. Few things create a bad impression more quickly than careless writing. A preview pane is provided when you prepare your comment. Please use it. Comments can be edited after submission (you’ll need to be logged in), but only until another comment is submitted.

The following quality issues are currently evaluated during moderation.

  • Comments adding nothing to the scientific discussion, in particular anonymous comments merely supporting another comment or voicing an opinion, are not suitable.
  • Non-scientific commentary should be avoided.
  • Supporting information should be provided, in the comment if possible. In particular, if you are highlighting suspected image irregularities, provide marked-up images to prove your assertions. If you are suggesting serious plagiarism, show a sufficient textual analysis. (We are not interested in the similarity of occasional sentences.)
  • If you believe a particular transformation underlies an image irregularity, you should provide strong evidence, typically by performing the transformation yourself and including the result.
  • Comments highlighting compression artefacts will be rejected. These are blocks that become visible at increased contrast but which reflect the complex nature of image compression (JPG format in particular) rather than the suspected “copy-and-paste” operation. Some discussion and links can be found here:
  • If you believe image parts have been (inadvertently) duplicated, check first whether the experimental design offers an innocent explanation. Particular points to look out for are gel reprobes, notably of total and phosphorylated forms of the same protein, and situations where more than one figure panel may have been composed from a single gel, causing the panels to share loading controls. In the latter case, the experimental conditions will be the same. Elision of whole lanes from a gel is not considered a concern except in recent articles (now that guidelines have been tightened).
  • The output from automatic image analysis tools (such as Error Level Analysis, ELA) is, in our experience, almost never interpreted correctly. Comments containing such analyses are usually rejected.
  • This is not a homework site. Although requests for explanation can be acceptable, you should provide evidence of having tried to understand the relevant sections of the paper (and, if appropriate, the cited literature) and also of understanding the significance of the issue raised. Put another way, we prefer comments that provide expert insight over those that display ignorance.
  • Criticism of specific analysis and modelling methods should explain why they are unreasonable/erroneous and significant. This requires engagement with the purpose, design and methods of the article. Appending a brain-dump to a random quotation is insufficient.
  • Criticism of articles simply for using Bayesian statistics is not considered useful. For such articles, it remains acceptable to discuss alternative choices of prior substantively.
  • General comments should be carefully linked to the specific article, and we may limit campaigns making such comments on many papers. More leeway is given for reviews, discussion papers and editorials.
  • Comments that are obviously erroneous or unclear will be rejected, in particular in the context of a series of misguided or potentially malicious comments. We acknowledge that this is potentially arbitrary, because it depends on the moderators’ expertise.
  • Conspiracy theories and disinformation will be blocked, including links to external sources containing such content.

Do authors receive alerts? Yes.

Authors are automatically alerted when their paper is commented. Commenters will encounter dialogs for verifying author email information.

Can I post external links? Please do.

We encourage you to post links to external information relevant to articles or discussion about them. These might include other articles that confirm or contradict the reported results, blog posts and newspaper articles. However, we discourage and may limit indiscriminate bulk linking campaigns.

How does moderation work?

In order to keep discussion factual, of high quality and polite as well as to minimize legal risks for everybody, we reserve the right to remove or edit comments that do not conform to these guidelines. Please help us by reporting any comments you believe do not respect our guidelines (a button is provided on each comment).

Anonymous comments and those from “greylisted” accounts only appear on the site after moderation, which can take up to a week.

PubPeer does not review comments scientifically and provides no warranty as to their veracity. All readers should evaluate comments for themselves.

Why doesn't PubPeer review comments scientifically?

PubPeer has grown as part of a reaction to the negative influence of editorial conflicts of interest, commercialism, errors and bias in the present system with its pre-publication review. We do not aim to reproduce it but to complement it with something different. Thus, PubPeer is designed around post-publication review and aims to facilitate open discussion. The philosophy driving the site is that authors should assume responsibility for assuring the quality, clarity, transparency and integrity of their publications. We make every effort to alert the authors to any comments and they are encouraged to respond. Such feedback can be extremely rapid and effective.

To implement scientific review on PubPeer would anyway be wholly impractical: PubPeer does not have the resources to address a quality-control problem that the planetary publishing industry has been unable to solve. Moreover, resolving many issues would require access to the original data, which are usually unavailable.

How can I ensure anonymity? Use Tor.

PubPeer gives users control of their anonymity and minimizes the user information held. Users who desire the strongest guarantee of anonymity should consider accessing the site via Tor ( using the Tor browser bundle.

Why can’t I find the paper I want to comment on?

This usually occurs because the DOI has not been correctly indexed. These problems are more frequent for recent papers.

Do you block specific commenters or comments about specific authors?

No user- or author-specific blocks are operated. In order to facilitate moderation, we can white-list or grey-list specific users. Comments from those on the grey list are moderated before posting; this can take several days and sometimes exceed the patience of the impatient. Furthermore, we have no way of identifying anonymous commenters. Moderation is based on the content of the comments not the identity of the commenter or of the author. Inaccurate statements about our policies are sometimes made on social media. Anybody interested in these issues is invited to fact-check with us.


My paper has been commented! What can I do?

PubPeer offers you a permanent right of reply. We encourage you to respond on the site. There are special facilities for indicating author responses. We believe that honest, careful and competent authors should provide “after sales service” for their publications, by clarifying any points that readers find unclear.

Many questions can be resolved by showing your original data. We encourage you to do so. An increasing number of journals require you to give access to your data or even to publish it directly, so there is now nothing unusual in making your data public. Although some authors still prefer only to show their data to journal editors, in our experience an opaque editorial statement is much less convincing than sharing the data publicly. Low-volume image and tabular data can be posted directly on the site (although tables may be tedious to format). Larger data sets are better submitted to a specialist provider (such as Dryad or figshare and then linked from a comment.

Did someone just accuse me of fraud?

Comments on PubPeer should not be automatically equated with allegations of misconduct, let alone credible ones. Numbers of comments should also be interpreted with great caution. Remember that comments can be about many different aspects of a paper: "major, minor, negative or positive". Every comment should be evaluated on its merits by the reader. Many comments concern research or presentation methods that users consider not to be best practice. A typical example would be differential splicing of gels or omission of loading controls. This does not mean that the result is erroneous or that misconduct has occurred! However, it might reduce the faith that readers place in the work. Even for apparently serious issues, there can often be an innocent explanation, which is why authors are encouraged to clarify and defend their work, and to join in the community effort to define best practice.

Is someone out to get me?

Authors sometimes complain that they are the subject of a malicious and systematic campaign to denigrate them and all of their work. We and other readers have no way of evaluating the motivations or potential conflicts of interests of anonymous commenters. However, everybody can evaluate the substance of a comment, which we feel is more informative and fundamental. If a comment is correct and useful, does it matter who made it or why? Moderation ensures that comments are factual and verifiable. Authors can respond. Readers must perform their own scientific evaluation.

Who did this to me?

PubPeer will never willingly reveal information that might help identify a commenter. We have already been to court to defend the anonymity of our commenters. PubPeer discourages ad hominem arguments and encourages discussion about the scientific substance.

Why does PubPeer allow comments that I know are wrong?

PubPeer does not review comments scientifically (see above), so factual comments conforming to our guidelines may still be wrong, misguided or unconvincing. For this reason we insist that readers must always make up their own minds about comment content. If you believe a comment is wrong or based upon a misunderstanding, we encourage you to post a brief explanation to share your insight and help educate the community. Of course, those best placed to explain a publication are usually its authors, which is why we do everything we can to encourage and facilitate their responses.

I answered, so can you make the comment disappear?

Thank you for engaging. We believe good scientists distinguish themselves by responding effectively to questions about their work. In most cases we will not consider removing comments, even if the authors apparently provide a convincing reply or explanation. Our viewpoint is that other readers may have similar questions and that it is therefore beneficial for the comment thread to remain publicly accessible. More philosophically, it is rarely possible to make a definitive judgement and PubPeer is certainly not in a position to do so systematically. Note also that we won't modify or remove comment threads because of journal actions, such as publication of a correction. In addition to our policy of keeping the complete discussion history publicly available, many journal corrections are opaque, superficial and unsatisfactory.

The whole world can read this forever?

That’s the point. Authors who don’t want their work discussed should consider not publishing it.

How can I convince ungracious commenters?

Authors occasionally use the critical tone of some comments as a pretext for not responding on the site. This is a personal choice. However, even if a specific commenter proves hard to convince, it is important to consider the wider audience of readers, who will evaluate the comment for themselves.

Can I claim a copyright violation?

We provide a procedure for notification of copyright violations by copyright holders. We will vigorously oppose unfounded or vexatious takedown notices. Note however, that reproduction of figures and text for the purpose of “criticism” falls squarely under the Fair Use exception of copyright legislation in the US, where PubPeer is incorporated and where the site is hosted. Note also that we back up external images and can therefore usually replace any taken down by external sites.

Why did PubPeer send me a nasty email? (We didn’t.)

We regret that you received a nasty email, but it probably wasn’t from us. PubPeer controls the domains, and Emails from any other domains are definitely not from us, even if they contain the word “pubpeer”. It is unfortunately very easy to spoof the “From” and “Reply-to” fields in email headers, although this can often be revealed by examining the full headers and routing information in detail.

PubPeer does automatically send simple alerts from the above domains to authors whose papers are commented. Authors can opt out of these.

User accounts

I lost my anonymous access code. Can I recover it?

No. Your only option is to create a new account. Please be more careful next time.

Can I choose my own pseudonym?

No. These are assigned randomly from the tree of life.

Why hasn’t my comment appeared?

For anonymous and pseudonym comments, this is most likely because the comment is awaiting moderation. Comment status for pseudonym accounts can be examined by logging in, after which comments are visible but marked as awaiting moderation. New pseudonym accounts are systematically “greylisted”, meaning that comments must be moderated. Accounts that make comments contravening our guidelines can be greylisted at any time. Moderation can take up to a week.

Can I get an account without a suitable publication?

No problem. Just contact us directly ( In most cases we will be happy to create an account for you manually.

PubPeer Integration

What are the browser plugins?

As explained on the plugins page ( ), the browser plugins highlight on any web page publications that have been discussed on PubPeer. In particular, this works on PubMed search results and journal web sites. Comment information is updated in the background and may take some time to propagate. There are plugins available for Firefox, Chrome and Safari.

What is the Zotero plugin?

Zotero is a free (libre) reference manager with many additional features ( We provide an extension that highlights within your Zotero library the references that have discussion on PubPeer. It is possible to mute or prioritise comments by particular users. The plugin is available on our extensions page (

How does Twitter integration work and what is the PubPeerBot?

PubPeer’s mission is to centralise and disseminate high-quality and useful commentary about published research. In addition to direct user comments, the site also links to high-quality blog posts, curation initiatives and expert commentary. One important source of scientific commentary has, however, been poorly represented: Twitter. The dynamic nature of Twitter and its dreadful search system renders much of that commentary ephemeral and difficult to discover. PubPeer offers a system for archiving this knowledge in accessible form---linked to the publication being discussed. Although it has always been possible to link to tweets from PubPeer, it is clear that much informative tweeting has not been reaching the site. So we decided that PubPeer “must go to the mountain”. Twitter integration is under development and the first implementation steps have now gone live.

If a user posts a link to a tweet, that tweet, and any connected thread, will be fully embedded in the PubPeer web page, making the content directly available to readers. Please note that such comments (the contents of the tweet or thread) are still subject to our commenting guidelines. If the comment is accepted, the PubPeerBot - a dedicated Twitter account - will reply to the thread with a link to the PubPeer page. You can find an example of such a reply and the linked, embedded thread here:

It is also possible to embed a tweet or thread from Twitter simply by invoking the PubPeerBot. It operates much like other twitter automata. You reply to the tweet or thread of interest, tagging @PubPeerBot and including in your tweet the DOI or arXiv ID of the paper to which the tweeting should be linked on PubPeer (other text in the tweet should be ignored). If all goes well, the thread will be linked, embedded and a reply generated (as described above). At the time of writing all comments are moderated, so the process will not be instantaneous. In the future we hope to extend our white/grey-listing system to Twitter users, which will allow posts from whitelisted users to appear immediately on the site.

You will also see the PubPeerBot alerting relevant Twitter users when new comments are added to a page with embedded tweets.

PubPeer is only as useful as its users are discriminating. We aim for Twitter integration to link to scientifically informative tweets. It is critically important that the service does not descend into spam. Please post accordingly; we shall run the service with this objective in mind.


Can I access PubPeer data?

We (will soon) have an API. Contact us to request a key.

PubPeer Foundation and site

Who runs this site?

The site is operated by the PubPeer Foundation; see About.

Terms of service

What are the terms of use?

By using the site, commenters agree to abide by the terms of service detailed here

What is your privacy policy?

We collect only the information required for site operation. PubPeer will never willingly reveal and will never sell user information. Further information is available here.