by reason for retraction – Retraction Watch

A researcher’s unusually high h-index gives a window into an expansive citation network

With an h-index of 75, computer scientist Thippa Reddy Gadekallu ranks among the world’s most highly cited researchers. But the speed and means of his ascent to those lofty heights of scholarship has been as remarkable as the achievement itself.

In less than a decade, Gadekallu, a professor at Zhejiang A&F University in China, has managed to bootstrap himself from scientific obscurity by collaborating with colleagues around the world who cite each other’s work in ways that have raised questions. In some years, Gadekallu received more citations than Yoshua Bengio, a pioneer in artificial intelligence and the top-rated computer scientist on Google Scholar.

Earlier work uncovered a network of reviewers on papers Gadekallu edited who frequently suggested adding citations to his work. A closer look by Retraction Watch shows the impact of that strategy on Gadekallu’s h-index, and reveals additional possible collaborators in the network.

Critics of birdsong study fight to be named in Nature’s retraction

A zebra finch in New South Wales, Australia. *Source: JJ Harrison/Wikimedia Commons (CC BY-SA 4.0)*

Researchers who flagged methodological issues in a paper on birdsong a year and a half before Nature retracted it say they should be credited in the editorial notice. But the editors have refused, with one telling the critics the paper was retracted for unrelated reasons.

The March 2024 study at the center of the dispute looked at how sexual selection may drive song patterns in male zebra finches. Nature retracted the paper last month because two of the synthetic song pairs used in the study were found to be unreliable, according to the notice. All three authors agreed to the retraction.

Todd Roberts, the paper’s corresponding author, told Retraction Watch the critics now asking for credit “prompted us to check the synthetic song pairs used in our paper.” He said his team did not do the reliability analysis of the pairs until after publication.

Widely criticized keto diet study retracted

A 2025 paper claiming the keto diet does not promote the formation of arterial plaques has been retracted after widespread criticism of the study’s methods and claims. The journal found “the identified errors are too great to be corrected with a corrigendum,” according to the March 11 retraction notice.

In April 2025, JACC: Advances published the study, which looked at plaque build-up in 100 otherwise generally healthy people who had experienced an increase in their cholesterol levels while being on a keto diet. The study claimed scans performed one year apart by the company Cleerly showed the diet was not associated with the development of arterial plaques.

This finding went against what previous studies had found, and it led to what Wired called “a new war in the nutrition world.”

How the media hypes “research that is absurd on its face”

Aaron Brown says his new book, Wrong Number: How to Extract Truth from a Blizzard of Quantitative Disinformation, “isn’t an exposé of fraud—Retraction Watch covers that ground. It’s about legitimate-looking research that is absurd on its face.”

Published this month by Wiley, Brown uses dozens of case studies to show “why widely reported and influential studies in top journals are not just wrong, but obviously and egregiously illogical or contrary to simple fact. My focus is less on the policy and statistical errors than on why no one seems to care,” he says.

Brown is a risk manager working in hedge fund management. He also teaches statistics at New York University and the University of California San Diego and writes columns for Reason and Bloomberg, among other outlets. We asked him to tell us more about how he thinks about the nexus of science, journalism and the publish-or-perish system that also pushes researchers to engage with non-experts to promote their work.

Feud between physicists ends in defamation verdict

A prolonged feud between two physicists in Italy that has played out for years in journal letters and blog posts has resulted in a defamation award for one of the rivals.

Lorenzo Iorio and Ignazio Ciufolini have sparred for more than 20 years over claims of plagiarism, sock puppetry and defamation. After two criminal lawsuits against Iorio failed, Ciufolini took the spat to civil court where the Court of Rieti on April 15 ordered Iorio to pay Ciufolini €15,000 (roughly US$17,500) for defaming Ciufolini in blogs and online journals.

In her eight-page decision, Honorary Judge Francesca Tosi said the statements Iorio made about Ciufolini, which date back to 2011, were more than “mere criticism” justifying a difference of opinion.

‘Comically bad’ datasets used to train clinical models for stroke and diabetes

A dataset on Kaggle purportedly showing people who have had a stroke includes images of Sylvester Stallone from *Rambo* and other celebrities. *Source*

Scrolling through an online image dataset, Adrian Barnett, a statistician at the Queensland University of Technology in Australia, pointed out a few familiar faces. Sylvester Stallone as Rambo, and then again on the red carpet. “This is just ridiculous,” Barnett said. George Clooney, Angelina Jolie and Daniel Craig all appear more than once, often with the same image. “You can see,” Barnett said, “this is just a comically bad dataset.”

This particular dataset, collected in a folder titled “droopy” and hosted on an open-source repository called Kaggle, underpins a paper published in Scientific Reports – not as a find-the-celebrity game, but as a training set for a predictive clinical model for early detection of strokes.

The paper is the most recent example of a much wider problem that Barnett and his Ph.D. student Alexander Gibson have documented with Kaggle, which is owned by Google and hosts datasets uploaded by users that researchers and machine learning practitioners can use to build predictive models. By examining two other Kaggle datasets on stroke and diabetes, both of which included tabular patient data, Gibson and Barnett traced how the data move through the scientific literature and in some cases, into clinical use. Their work, described in a preprint posted to medRxiv in February, already has led to several retractions of the papers using these dubious datasets.

Reviewer finds ‘top pharmaceutical scientist’ has a self-citation problem

Daniel Bar-Shalom, a pharmacist at the University of Copenhagen, was incensed.

He’d been asked to review a manuscript by Muhammad Imran Qadir, an associate professor at Bahauddin Zakariya University in Multan, Pakistan. According to his institution’s website, Qadir was the “top pharmaceutical scientist” in the country. But Bar-Shalom thought the introduction to the paper felt like it could have been written by a student. The real problems started in the middle of the article, however, in what Bar-Shalom came to think of as “the fill of a shit sandwich.”

There, sprinkled throughout the text, were several irrelevant and trivial sentences. “Novel drugs and vaccines are being made or designed by scientists,” read one. “Genomics and proteomics have been longstanding tools in the creation of novel drugs,” another stated.

Swiss court clears sleuth in defamation case, awards him legal costs

An appeals court in Switzerland has overturned a 2025 defamation conviction against a sleuth who had identified dozens of conference proceedings with signs of citation manipulation. The ruling orders the plaintiff to pay the sleuth’s legal expenses.

The judgment clears Solal Pirelli, a software engineer in Lausanne, in a lawsuit filed against him in 2023 by Shadi Aljawarneh, a computer scientist at the Jordan University of Science and Technology.

The case stemmed from a blog post Pirelli published in January 2023 summarizing problems with the proceedings of conferences organized under the auspices of the Association for Computing Machinery (ACM). Aljawarneh was the chair of most of the conferences, and the proceedings included signs of citation stuffing in Aljawarneh’s favor.

One in 277 PubMed-indexed papers in 2026 shows fabricated references, says analysis

*Figure from correspondence to* The Lancet by Maxim Topaz and colleagues.

Fabricated citations in the biomedical literature have increased 12-fold in two years, according to an audit of nearly 2.5 million papers published as a letter to The Lancet today.

The analysis of articles indexed in PubMed found that about one in 277 papers published in the first seven weeks of 2026 referenced a paper that didn’t exist. That was a jump from 2025’s rate of one in 458 and 2023’s one in 2,828. The researchers, led by Maxim Topaz of Columbia University’s Data Science Institute, used AI to “distinguish genuine fabrications from formatting discrepancies such as informally abbreviated titles.”

Topaz’s group located the sharpest increase in hallucinated references in mid-2024, which they note coincided with the rise of AI writing tools. The findings come as Nature reported last month that tens of thousands of publications from 2025 “might include invalid references generated by AI.” Retraction Watch has seen its fair share of reports of hallucinated citations generated by LLMs like ChatGPT.

Russian news outlets hailed a cancer breakthrough, but the retraction went unnoticed

In August 2021, several news outlets in Russia reported a cancer breakthrough: Researchers at the chemistry and biophysics institutes affiliated with the Russian Academy of Sciences had developed a new kind of nanoparticle that could help detect breast cancer in an MRI and kill tumor cells at the same time. State-run media and several Russian science outlets reported on the study over the next few days.

But four years later, Journal of Materials Chemistry B, the journal that had published the paper, retracted it.

The publisher, the Royal Society of Chemistry, found the paper contained repeating patterns in the electron microscopy data and several images depicting cells that were identical to those included in a later paper with a number of the same authors. The authors — who include Vladimir Ivanov, director of Russia’s Kurnakov Institute of General and Inorganic Chemistry, and Alexander Baranchikov, also at the institute — all agreed to the retraction.

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