Studies produced by a suspected paper mill are frequently cited in patents, clinical guidelines and policy documents, according to a new analysis.
The work, posted on arXiv on August 31, examined the fate of nearly 2,000 academic papers with one common factor: At least one coauthor lists the Pharmakon Neuroscience Network (PNN) as an institutional affiliation.
But there’s one problem: the PNN is not a real network of scientists. Instead, it’s an authorship-for-sale scheme, as Retraction Watch reported in 2022.
Papers listing PNN as an affiliation started to surface in academic papers in 2019 and often included coauthors based in several different countries. Author lists with researchers who haven’t collaborated in the past, don’t have any past common coauthors, or who work in entirely different fields are a sign a paper may originate from a paper mill.
To learn what influence paper mill studies may be having, Federica Silvi and Leslie McIntosh of scholarly services firm Digital Science in London studied 1,975 articles by PNN-affiliated authors and examined where those papers were cited.
Using the scholarly database Dimensions, the authors found that 480 papers mentioning PNN were cited in patents, 57 were referenced in policy documents, and 12 appeared in clinical guidelines.
“It’s a problem for sure,” said Malcolm Macleod, a neurologist and research integrity expert at the University of Edinburgh in Scotland, referring to paper mill studies receiving citations.
Another recently published study suggests that just over 400 U.S. patents contain references to retracted papers.
Most of the citations in clinical guidelines were to papers coauthored by pharmaceutical researcher Shaker Mousa, who was found to have faked data in two papers in a 2024 investigation by the U.S. Office of Research Integrity. By our count, Mousa — who was formerly the vice provost for research at the Albany College of Pharmacy and Health Sciences in New York — has at least 16 retractions to his name.
But it’s not clear if those mentions in clinical guidelines mean the recommendations were directly based on evidence from the problematic papers, McIntosh, vice president of research integrity and security at Digital Science, told Retraction Watch. “Clinical guidelines also have a lot of citations generally,” McIntosh said. “We don’t have a silver bullet saying that this information is misdirecting clinical guidelines severely.”
Macleod said one would need to consider how the guideline would have been different if the paper mill study didn’t exist. Many such studies churn out results in line with what the rest of the literature reports, he noted, in which case, it wouldn’t make much difference if these studies were cited in the guidelines. Still, “in principle, it’s highly problematic,” he said. Putting an expression of concern to any clinical guideline citing a questionable study would be a good step, he added.
Silvi and McIntosh also tried to assess how often grant applications cite paper mill studies, but that’s difficult to determine as funders reject many proposals and the details of proposals are not published anywhere, McIntosh said. The only avenue to explore is whether researchers in the network go on to attract funding from legitimate funders after being exposed, she said. Nevertheless, “the whole corpus of your CV is used when you submit a grant, even if you’re only citing some of your own work,” she said.
Since McIntosh’s revelations about PNN in the last few years, papers mentioning the network as an affiliation have ceased, she said: “They are now using other names.”
McIntosh and Silvi also studied the works of 278 researchers who collectively coauthored the papers in the PNN dataset. They found that 90% of these authors continued to publish studies after Retraction Watch reported on the network in 2022.
Since then, those authors have collectively published 12,508 studies, McIntosh and Silvi reported, and attracted significant funding to do so. Around a quarter of the researchers received at least one grant since the 2022 exposé, she noted. One of those papers has been retracted.
Jennifer Byrne, an oncologist and a research integrity expert at the University of Sydney in Australia who has studied paper mill article citations in cancer, said it would be interesting to know whether earlier PNN papers are the ones cited in patents, clinical guidelines and grant applications, since citations take time to accumulate.
“Some coauthors of paper-mill supported papers might not be aware of their paper mill origins, and so some applicants who have coauthored paper mill papers could apply for grants in good faith,” Byrne said. “That said, researchers who have knowingly used paper mills to bolster their track record might also be willing to misuse grant funds, which is a problem in itself, regardless of the scientific value of the work that is funded.”
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