Economist Peter Nijkamp did not use false research data. This is the conclusion drawn by a committee made up of Amsterdam VU University and VU Academic Medical Centre specialists. The verdict is the conclusion, for now, to a case which has been ongoing for over two years.

Three scientists who used to be affiliated with Amsterdam VU University had committed data fraud, an anonymous source alleged in June 2014 in a letter to VU University’s ombudsman. Eight of the allegedly fraudulent articles had been authored by Peter Nijkamp and his colleague Karima Kourtit, while seven had been written by Tüzin Baycan, Nijkamp and several other co-authors.

All these accusations were unfounded, a special fact-finding committee, the Struiksma Committee, found in a report which was released Wednesday. The Committee stated that it had no grounds whatsoever to assume that Nijkamp’s data had been made up or used in an unacceptable manner.

Protracted scandal

The report released on Thursday is the latest in a chain of events, which started in May 2013 with an anonymous allegation about Karima Kourtit’s PhD dissertation. An anonymous party identifying only as ‘NN’ accused Kourtit of plagiarism, science journalist Frank van Kolfschooten wrote in an ‘introduction’ to the rather complex case.

A committee led by Pieter Drenth established that the dissertation did indeed contain instances of plagiarism. Kourtit was granted the opportunity to rewrite her thesis and was awarded a doctorate, after all. The case also had consequences for her PhD supervisor, Peter Nijkamp, who resigned from his position.

In a throw-away line, the fact-finding committee reported that several chapters co-authored by Nijkamp contained instances of ‘self-plagiarism’, i.e., previously published work which had been re-used without a proper citation.


The above led NRC Handelsblad to look into the case. In January 2014, the newspaper accused Nijkamp of plagiarism and self-plagiarism. As a result, VU University decided to establish a committee tasked with investigating the well-reputed professor’s entire oeuvre: the Zwemmer Committee, which found in March 2015 that Nijkamp had copied large passages of text from previous publications with alarming frequency. The report stated that he was guilty of ‘systematic cutting and pasting’.

Second accusation

In the meantime, the anonymous ‘NN’ had submitted a second allegation in November 2013 concerning plagiarism in sixteen articles published by Kourtit, many of which had been co-authored by Nijkamp. VU University established another fact-finding committee, the second Drenth Committee.

In the summer of 2014, the Committee judged that three articles written by Kourtit and Nijkamp did indeed contain instances of plagiarism. However, when the academics appealed this verdict, the National Board for Research Integrity (LOWI) found that the two scientists had not been guilty of a breach of scientific integrity, but of ‘culpable inaccuracy’ at most.

LOWI also reprimanded VU University, because the university had no idea who ‘NN’ might be. Completely anonymous accusations should only be considered in truly exceptional cases, LOWI found.

LOWI also wondered just how pure the anonymous whistleblower’s motives were. The National Board stated that it was struck by the fact that ‘NN’ had found instances of plagiarism in sixteen articles, but had only accused Kourtit of plagiarism, even though thirteen of the articles in question had been co-authored by at least one other academic.

anonieme klager wel helemaal zuiver zijn. Het landelijk orgaan vindt het opvallend dat ‘NN’ in zestien publicaties plagiaat vond maar alleen Kourtit ervan beschuldigde, terwijl dertien van die publicaties waren geschreven met één of meerdere coauteurs.

Allegation No. 3

But while accusation No. 2 was still being looked into, ‘NN’ submitted a third allegation in June 2014, this time about data manipulation. This was the accusation which resulted in the report released by the Struiksma Committee yesterday.

From now on, VU University will no longer consider completely anonymous accusations, the university has announced. However, the three accusations submitted over the last few years could not have been ignored, the Board of Governors stated. ‘The nature of the accusations was always so specific that the Board of Governors could not but find that these allegations could not be brushed aside without some form of investigation,’ the University said in a statement.


Professor Nijkamp has by now retired. He had been a Professor of Regional Economics and Economic Geography with VU University since the 1970s. Nijkamp was a highly decorated scientist. He is a recipient of the Spinoza Prize, the highest-rated award bestowed on Dutch scientists, and chaired the research funder NWO.

Wednesday, he told de Volkskrant that he demanded ‘generous apologies and rehabilitation’ from VU University. If he does not receive them, he is willing to take the matter to court.