A PhD defense at the Faculty of Social Sciences has been postponed. The Promotion Board has concerns about the reliability of a dataset provided by dismissed researcher G. The case is currently under investigation.

The PhD candidate in question is a co-author of several publications by G., the dismissed scientist who manipulated research results. One of the articles they wrote together is the publication that is central to the integrity investigation. That research, however, is not part of the dissertation. The candidate is said to have used a dataset from G. in one chapter.

‘Nothing unusual’

The defense, which had been scheduled for the second half of January, has therefore been postponed. The Promotion Board has concerns about part of the dissertation following the recent case of scientific fraud, says Professor of Developmental Psychology Toon Cillessen, chair of the manuscript committee. “The Promotion Board informed us of this.” He does not know who is conducting the investigation or when it will be completed.

The dissertation had already been approved by the manuscript committee. “We did not notice anything unusual,” says Cillessen. “There are concerns about one article in the dissertation for which data may not be correct. However, these data did not lead to any surprising or remarkable conclusions. If the follow-up investigation does not reveal anything further, this may have no additional implications for the PhD candidate, and I expect the defense can proceed as planned.”

Radboud Repository

Surprisingly, a PDF version of the dissertation can already be found in the Radboud Repository, the university database that includes dissertations and other academic publications. In principle, a dissertation should only appear online after the defense has taken place. The fact that this has already happened despite the postponement may indicate that the decision to postpone was made at a late stage.

This also aligns with the timeline of the integrity investigation involving G. On January 12, The Executive Board (CvB) declared a complaint against him to be well-founded, not long before the scheduled defense. On March 23, the university publicly announced that the complaint was substantiated. G. had improperly altered and fabricated data in a scientific publication from 2025, thereby violating academic integrity. The board stated it would enter discussions with the integrity committee and the dean “about possible measures to be taken”.

For the candidate, it was difficult, as everything for the defense had already been arranged

Cillessen does not know how the dissertation ended up in the Radboud Repository. “The dissertation had already been printed in its current form. For the candidate, the postponement was difficult, as everything for the defense had already been arranged.”

Due diligence

A new date for the defense has not yet been set. “I expect the defense will take place soon,” says Dean Evelyn Kroesbergen. She can’t say when exactly and she declined to answer other questions about the case. Up to the end of June 2026, eleven PhD defenses have been announced at the Faculty of Social Sciences, but this defense is not yet listed among them.

The intended supervisor of the PhD candidate, Professor Wolter Pieters, wrote in an email that the defense was postponed out of a need for due diligence. “Because much is still unclear and we also want to protect the PhD candidate from negative consequences as long as that is the case, I cannot comment on other questions.” The co-supervisor, Joyce Schleu, declined to answer questions and referred inquiries to Dean Kroesbergen. The PhD candidate was also contacted but did not respond to questions from Vox.