MANY scientific studies are flawed. Often, the reason is poor methodology. Sometimes, it is outright fraud. The conventional means of correction—a letter to the journal concerned—can take months. But there is now an alternative. PubPeer is a website that lets people comment anonymously on research papers and so, in theory, helps purge the scientific literature of erroneous findings more speedily.

Since its launch in 2012, PubPeer has alerted scientists to mistakes and image manipulation in papers, and exposed cases of misconduct. But it has also attracted criticism, not least from journal editors, some of whom argue anonymity’s cloak lets vendettas flourish unchecked. Now the site is embroiled in a court case that tests the limits of free speech under America’s First Amendment, and may define what it is permissible for researchers to say online and anonymously about science.

The proceedings centre on discussions that began on the site in November 2013. These highlighted apparent similarities between images showing the results of different experiments in papers by Fazlul Sarkar, a cancer researcher who was then based at Wayne State University in Detroit. Dr Sarkar alleges that certain commenters insinuated he was guilty of scientific fraud. The comments, he says, together with anonymous e-mails sent to the University of Mississippi, cost him the offer of a professorship there. In October 2014 he sued the commenters for defamation and subpoenaed PubPeer to disclose their identities. A court is now expected to decide whether the site will be forced to do so.

The American Civil Liberties Union has taken on the case on PubPeer’s behalf. Its lawyer, Alex Abdo, says that the anonymity of PubPeer’s commenters is protected by American law unless Dr Sarkar can provide evidence that their statements are false and have damaged his reputation. Evidence filed by PubPeer from John Krueger, an image-analysis expert, states the images in question “did not depict different experiments as they purported to” or contained other “irregularities”, and may have been manipulated. Mr Abdo asserts that the comments identified by Dr Sarkar are not defamatory. Therefore PubPeer should not be forced to disclose the commenters’ identities.

Who blows the whistle?

By contrast, Dr Sarkar’s lawyer, Nick Roumel, argues the law should not provide anonymous commenters with more protection than it gives those who post under their real names. It is impossible to contact PubPeer’s commenters to establish what they know about the allegations without knowing their identities, he says.

In March 2015 a judge at the Wayne County Circuit Court agreed that PubPeer need not disclose the identities of any of its commenters except for one. That commenter had confirmed on the site that he or she had notified Wayne State University of problems with Dr Sarkar’s papers. A prolific pseudonymous whistle-blower named Clare Francis is known to have e-mailed Wayne State in November 2013, to notify it of concerns with Dr Sarkar’s work aired on PubPeer, adding in her e-mail (if, indeed, “Clare Francis” is a woman) that, in some cases, they amounted to “what many think of as scientific misconduct.” Whether Clare Francis and the subject of the judge’s order are the same is not clear.

Both sides lodged appeals against the ruling. PubPeer objects to revealing the identity of the last commenter. Mr Roumel wants to know the identities of them all.

Two goliaths of information technology, Google and Twitter, lodged a brief in support of PubPeer in January 2016. So did two giants of science: Harold Varmus, a Nobel prize-winning cancer researcher, and Bruce Alberts, a former president of the National Academy of Sciences. They argued that the First Amendment protects “unfettered scientific discourse”.

On October 19th the Scientist, a magazine, published some findings of a misconduct investigation carried out by Wayne State University in 2015. The report of this investigation, which the magazine obtained under America’s Freedom of Information Act, states that Dr Sarkar “engaged in and permitted (and tacitly encouraged) intentional and knowing fabrication, falsification, and/or plagiarism of data”. Furthermore, 18 papers from Dr Sarkar’s laboratory have been retracted from five different journals.

Dr Sarkar rejects all the investigation’s findings. He states that he provided the correct images to the university but his explanations of how the errors occurred were dismissed out of hand. Despite his having more than 500 peer-reviewed papers to his name, his reputation has been destroyed because of “minor errors in a few articles,” he says. Philip Cunningham, who convened the Wayne State panel that investigated Dr Sarkar, says all evidence was carefully considered and the university stands by the integrity and accuracy of the report.

Normally, neither Dr Sarkar’s retractions nor Wayne State University’s report would have any bearing on the case because appeals can only consider evidence presented during an earlier trial. But on October 28th, in what may be a decisive ruling, the court allowed PubPeer to enter the Scientist’s story about the report into the official record of the case. The results of the appeal hearing itself, which took place on October 4th, are expected imminently.

Whichever way that decision goes, at least one side is likely to appeal against it. But however the case eventually ends, its outcome will affect the process of “open peer review” that PubPeer is pioneering by determining whether or not anonymous critics of scientific papers can, in the last analysis, retain their anonymity.