Dutch university investigates psychologist Yannick Griep as nine research papers face retraction

Dismissal and initial findings

Radboud University in Nijmegen dismissed associate professor Yannick Griep without notice in late 2024 after discovering fraudulent expense claims and invoice manipulation regarding compensation for research subjects. Following his dismissal, university colleagues examined Griep's publicly available research datasets and identified widespread anomalies in his work on workplace behavior. A subsequent investigation by the university's Scientific Integrity Committee revealed that Griep had altered and fabricated experimental data, resulting in extensive duplications throughout his research files. The Belgian psychologist had joined the Radboud faculty in late 2019, specializing in work and organizational psychology after authoring nearly 100 scientific publications. Faculty leadership described the scale of the case as the largest encountered during their administrative tenure.

In my years as an administrator I have not previously encountered such a large case.

Retraction of research papers

The investigation led to the formal retraction of Griep's study on leadership behavior, titled the Bokito-manager study, which was originally published in the Journal of Business Research. The Scientific Integrity Committee determined that datasets for the 2025 publication contained fabricated entries and extensive data recycling, while university magazine Vox reported that data appeared cut, pasted, and shuffled across spreadsheets. When questioned by the investigative committee, Griep maintained that the irregularities resulted from human or technical error rather than deliberate misconduct. In addition to the Journal of Business Research retraction, academic publisher Sage retracted eight other articles co-authored by Griep during the summer of 2026. Those eight papers appeared in a management science journal where Griep served as editor-in-chief after leaving his post in Nijmegen.

Peer review manipulation and spreading inquiries

Publisher Sage initiated the retractions following an internal review that uncovered irregularities in how the eight articles had been peer reviewed prior to publication. Scientific peer review requires independent researchers to evaluate manuscripts, but Sage found that Griep had managed the review process himself for those submissions. University magazine Vox reported that Griep fabricated the review feedback for at least one publication, citing a statement from a co-author on the paper. The fallout expanded in early 2026 when a doctoral dissertation defense at Radboud University was postponed at the last minute. The doctoral candidate, who is Griep's partner, had used datasets supplied by the former associate professor, prompting concerns about the integrity of the underlying findings.

Broader career record

The revelations prompted three separate integrity investigations into Griep's academic output, two of which remain active. Prior to his appointment in Nijmegen in late 2019, Griep held academic positions at the Vrije Universiteit Brussel in Belgium, the University of Calgary in Canada, and academic institutions in South Africa. Former colleagues at both VUB in Brussels and Calgary had previously raised doubts regarding the reliability of his scientific data. With nine papers retracted across multiple publications and additional datasets under review, the inquiry represents one of the largest scientific integrity cases in the Netherlands in recent years.