Belgian Scientist Accused in Major Dutch Fraud Case

A Belgian work and organizational psychologist has been found to have manipulated and fabricated research data in what Dutch daily de Volkskrant describes as one of the largest scientific integrity cases the Netherlands has seen in recent years. Yannick Griep, a former associate professor at Radboud University in Nijmegen, was the subject of a ruling by the university’s Scientific Integrity Committee, which found the complaint against him valid, according to Het Laatste Nieuws.

The case, which has expanded from an initial invoice-fraud dismissal into a multi-front scandal involving retracted publications and a fabricated peer-review process, has raised serious concerns about the reliability of the affected studies and prompted a wider investigation into Griep’s broader body of work.

The Findings

The integrity committee’s inquiry centred on a 2025 study published in the Journal of Business Research (Elsevier), a survey of 274 participants examining how abusive leadership — colloquially known as “Bokito behaviour,” after the famously aggressive Dutch zoo gorilla — affects employees who witness it.

When complainants examined the dataset posted to the Open Science Framework, they found that 233 of the 274 subjects had values identical to those of another participant — a statistical near-impossibility. Several data columns appeared to have been copied, pasted, and then jumbled. The original raw data files could no longer be found anywhere.

As Vox, Radboud University’s independent magazine, reported, investigators suspect the research may never have actually taken place, and that Griep instead reused data from a former master’s student’s thesis concerning an entirely different study. The committee concluded that the original thesis “may have served as inspiration for the fabrication of the dataset.”

The committee did not find Griep’s defense convincing. During proceedings, he argued the duplicate data points were the result of “a human or technical error and not of intent.” The committee rejected that explanation, citing the sheer number of duplicates and the inconsistency within them, and noted that it was difficult to believe the authors had not noticed the duplicates earlier, given how conspicuous they were.

Griep has consistently denied wrongdoing. In an appeal to the national scientific body LOWI — which was declared inadmissible because he filed it a month late — he stated: “I have never, absolutely never, fabricated or manipulated data, and I would never do so.”

From Invoice Fraud to Retractions

The integrity case was not Griep’s first run-in with his employer. He was summarily dismissed by Radboud at the end of 2024 after an observant employee noticed that an invoice for participant reimbursements amounting to roughly €2,500 had been submitted using a different font — a telltale sign of manipulation. Griep challenged the dismissal, and the dispute was ultimately settled.

Following the integrity investigation, Radboud University’s Executive Board declared the complaint valid and opened a further inquiry into other publications. As Radboud University announced, the board decided to commission the wider investigation “because of the seriousness of the breach of research integrity.”

The 2025 Journal of Business Research article was retracted in April 2026. Separately, the publisher Sage retracted eight further articles by Griep from the journal Group & Organization Management (GOM), where he had served as editor-in-chief from April 2022 to March 2026. As Retraction Watch reported, six of the papers were retracted at the publisher’s request and two at the request of co-authors. Seventeen other Griep papers in the journal remain under investigation.

A Fabricated Peer Review

The retractions were prompted not by the scientific content of the GOM articles but by a compromised review process — because Griep, as editor-in-chief, administered the peer review of articles he had also co-authored.

The full extent emerged through a co-author. James Lemoine, an organizational psychologist at the University at Buffalo, uncovered the scheme after a tip and documented his findings publicly. According to Vox, Lemoine found that the fellow editors who were supposedly responsible for overseeing one 2024 article had never been asked and were unaware it existed. The supposed peer reviewers held fake GOM accounts.

Confronted, Griep vaguely admitted he may have handled the paper himself, claiming it was to expedite publication in the new “GOM Now” section. “If an author of a paper also acted as the handling editor, making all of the publication decisions, this seemed like a major ethical violation deserving of a retraction,” Lemoine wrote. He described the episode as “a major betrayal of trust,” adding: “None of us are perfect, but one of the greatest things about us is our potential to learn from our mistakes.”

Sage’s publisher’s note confirmed the concern: “As the peer-review process was administered by the former Editor in Chief, who is also the co-author of the articles, the objectivity of the peer-review process has been compromised.” The publisher added that the retraction related only to the review process and that no determination had been made regarding the articles’ scientific content.

Prior Concerns in Belgium and Canada

The case has also cast a retrospective light on Griep’s earlier career. According to Vox, questions about his scientific integrity had surfaced years earlier at the Vrije Universiteit Brussel in Belgium and at the University of Calgary in Canada, where he held a tenure-track post. No formal fraud investigation was launched in Belgium because of a lack of hard evidence.

Griep’s former PhD supervisor at the Vrije Universiteit Brussel, Tim Vantilborgh, described how analyses began producing implausible results and how Griep repeatedly failed to provide the underlying data. The collaboration was formally ended by colleagues. “The thought ‘you are not who I thought you were’ went through my head,” Vantilborgh told Vox.

Vox has described Griep as a “rising star” in his field — a prolific and charismatic researcher with roughly a hundred publications and more than 1,500 citations. The magazine reported that concerns about his handling of data, ethics, and supervision had lingered among some colleagues even as his reputation grew.

What’s Next

Radboud’s follow-up investigation into Griep’s other publications remains ongoing, and the status of a special professorship he held at North-West University in Potchefstroom, South Africa, is unclear. Griep has left his editorship at GOM and now works as a senior adviser at Samergo, a Dutch healthcare consultancy.

The case underscores mounting pressure on institutions to police research integrity — and the difficulty of detecting fabricated data once it has entered the scientific record. With 17 further GOM papers still under scrutiny and other datasets described by Vox as no longer accessible for verification, the full scale of the affair may not be known for some time. For the affected journals and co-authors, the immediate question is whether the findings will hold — and for the research community, what the case reveals about the incentives that can reward productivity over correctness.