According to Bishop, most researchers involved in peer-review mills are motivated by the desire to increase their citation counts. Citation metrics can influence university hiring, promotion and tenure decisions, as well as institutional rankings and research funding. As citation numbers become a more important measure of academic performance, “the more people will try to game the citations”, she says.
Evidence of a connection between peer-review manipulation and citation gaming comes from researchers who submit duplicate review reports and frequently cite their own work. Fabian Wittmers, a marine biologist and science sleuth at Oregon State University in Corvallis, identifies engineer Rabiul Awual as one example. Awual’s research has been cited almost 43,000 times according to Google Scholar, but Wittmers says the figure is partly linked to a long-running pattern of excessive self-citation. In a now-retracted study on caesium removal from wastewater6, Awual and his co-authors cited their own research 123 times. Wittmers considers 10–15 self-citations per paper to be an acceptable limit. The retraction notice, issued in October 2025, states that most of the citations added during revision were of “either borderline relevance or no relevance whatsoever to the article” and describes the practice as “a violation of publishing ethics”. The notice also says that the authors disagree with the reasons for the retraction.
When contacted about their disagreement with the retraction, co-author Nazmul Hasan asked Nature not to send further e-mails. Other co-authors, including Awual, did not provide meaningful responses to requests for comment and instead replied with hostility and profanity.
Awual’s peer-review activity may have generated additional citations. Publicly available reviews he wrote for papers published in MDPI journals show that he often reused similar wording and requested citations to his own studies. Wittmers says he has identified dozens of studies in Elsevier journals that cite large numbers of Awual’s papers. Although the reviews for those studies are not public, Wittmers suspects that Awual or his collaborators may have reviewed some of them.
For example, a 2022 study7 published in Food Chemistry examined the structural properties of dough used in steamed bread but cited four of Awual’s wastewater-treatment papers. “This is not a one-off situation. There’s multiple papers in Food Chemistry where papers by Awual were cited that make no sense,” says Wittmers.
Wittmers believes that these peer-review practices may help Awual and his collaborators secure citations for their research, which he considers to be of poor quality. In a 2025 PubPeer post, Wittmers reported alleged image duplication in six of Awual’s studies. “No one wants to cite these paper-mill products,” Wittmers says. “So you need to request that they get cited. And that’s why you review a lot.”
When invited to respond to Wittmers’ allegations concerning excessive self-citation, peer-review mills and image duplication, Awual asked Nature to stop sending “foolish” e-mails.
One author of a study published in an Elsevier journal, who requested anonymity to avoid potential conflicts with reviewers or publishers, says they felt pressured to cite Awual’s research after receiving an anonymous peer-review report. Alongside general recommendations to revise the title and explain the study’s novelty in the introduction, the review included numerous requests for additional references. The reviewer ended by asking to see the revised manuscript, which the author interpreted as a possible threat of rejection if the citation requests were not followed. “I felt pressured by the reviewer,” the author says.
The author says they asked the journal to investigate the questionable references and will notify editors if similar reviewer reports are received in the future. More broadly, they report a concerning rise in incoherent peer reviews that appear to discuss entirely different manuscripts. “It seems that many journals do not perform even minimal checks on the coherence and relevance of peer reviews, leaving scientists vulnerable to inadequate reviewing practices,” they note.
Asked how Elsevier handles potentially inappropriate reviewer reports, a spokesperson said the publisher has policies addressing citation manipulation and provides training to help editors identify such behavior. “Reviewers should not suggest citations to the reviewer’s (or their associates’) work unless the suggested citations are for genuine scientific reasons,” the policies state. “Editors may remove citations that, in their view, are inappropriate from reviewer comments.”
It is unclear why Awual was invited to review papers outside his area of scientific expertise. Wittmers says peer-review mills may appear attractive to journal editors who are struggling to find qualified reviewers within an increasingly overworked academic community. Because review mills can respond quickly to invitations, they may also help journals reduce the time required to complete peer review.
Nature journalists asked Springer Nature to comment on its procedures for addressing coercive peer review and protecting research integrity. A spokesperson said the publisher is working to identify and prevent review-mill activity by analyzing peer-review content and investigating networks of potentially compromised individuals.
“For cases where we can document repeated attempts to manipulate citation practices, individuals are suppressed from acting as reviewers in future and may be subject to further sanctions, such as being blocked from publishing in our journals,” the spokesperson says. Authors can report coercive citation requests to a journal’s editor-in-chief or publisher, while editors should notify the appropriate publishing contact, they added.
Source: www.nature.com