[1] Before embarking on his doctoral research, in 1991–1992, Stapel returned to the US for study, undertaking a program on behavioral decision making at the University of Chicago's Graduate School of Business.
After gaining his doctorate, Stapel continued at UvA as a fellow of the Royal Netherlands Academy of Arts and Sciences (KNAW) for three years.
[9] He voluntarily surrendered his PhD title to the University of Amsterdam in November 2011, noting that his "behavior of the past years are inconsistent with the duties associated with the doctorate".
[14][15][16] According to the first findings, out of an initial batch of twenty Stapel publications studied by the Levelt committee, twelve journal articles were fabricated and three contributions to books were also fraudulent.
[18] "We have some 30 papers in peer-reviewed journals where we are actually sure that they are fake, and there are more to come," Pim Levelt, chair of the committee investigating Stapel's work said in a media statement.
[19] The Levelt joint committees' reports acknowledged three unnamed young Tilburg University researchers as the whistleblowers for the case.
[13] Curiosity regarding datasets was discouraged by Stapel and, at times, persistent or perceptive questioning would be met with apparent hostility.
In one case the Levelt committee reports, a PhD student who was querying unusual data was told by Stapel: "If you want to be taken on here you will have to demonstrate that you can get something finished, so just write up the results."
[23] As his process for fraudulent research developed, by his Tilburg years his general method was to formulate in full all the elements of a proposed study – an experiment, with its theoretical grounding, the hypotheses, methods, stimuli, questionnaires, and even participants' rewards – and then create the fictitious data which he would then provide to colleagues and students for further analysis.
For example, several experiments were to be run in schools; Stapel made it known that he had access to these by special arrangements which would be endangered by involving other researchers.
The purported schools preferred to deal with Stapel alone, whom they knew and trusted and would be bothered by having additional, unknown researchers involved.
The Levelt report concludes that his academic reputation was, in part, the reason his illicit activities were able to continue for such a length of time.
[28][29][30] The interim report stated that Stapel had caused severe damage to young people at the beginning of their careers, as well as to the general confidence in science, in particular social psychology.
[31] Despite being critical of an overarching shortfall in collective academic responsibility, the investigating committees emphasized that Stapel acted alone in all cases of known misconduct.
[33] In June 2013 Stapel agreed, in a settlement with the prosecutor, to perform 120 hours of community service and to lose the right to some benefits associated with his former job equivalent to a year and a half's worth of salary.
I realize that by this behavior I have left my immediate colleagues bewildered and angry and have put my field of study, social psychology, in a bad light.
In a review for the Association for Psychological Science's Observer, Stapel's Ontsporing ('Derailment'), a book-length memoir, is described by Dutch psychologists Denny Borsboom and Eric-Jan Wagenmakers as "revealing".
The reviewers suggest the memoir may provide insights into systemic failures within research science, saying that in his account of the affair, "Stapel appears to underscore the conclusions from the Levelt committee" in this regard.
"[37] The reviewers describe the final chapter of the book as "unexpectedly beautiful" but consider that many of its lines are "copied" from the works of writers Raymond Carver and James Joyce, without due acknowledgement.
[38] Borsboom and Wagenmakers reviewed the Dutch language edition; the English translation of Stapel's Ontsporing by Nicholas J. L. Brown includes a note regarding "Chapter 10 ½":[39]This last chapter is my own reinterpretation of some of the final lines of Raymond Carver's poem "The Gift" (from the collection Ultramarine, 1986, Random House, New York), into which I have also woven a couple of lines from the ending of James Joyce's story "The Dead" (from The Dubliners, 1990, Bantam Classics, New York).
Several chapters written or coauthored by Stapel in reference books were called into question in the Flawed Science report.
The Noort committee, examining publications stemming from Stapel's time at the University of Groningen, also considered a number of book chapters in edited works suspect.
In the case of these works, having less surviving original data available to examine, the Noort committee concluded with less certainty only "evidence of fraud".
In the Flawed Science report they note the following chapters, under the heading: "The following book chapters are (partly) based on findings of articles, in which the Committees have found evidence of fraud:"[43] The first journal article retraction occurred a month after Tilburg University announced that it had found evidence of fraud in Stapel's work.
In December 2011, the journal Science posted a retraction notice for Stapel's co-authored paper entitled "Coping with chaos: How disordered contexts promote stereotyping and discrimination".
On 31 October 2011, the University of Tilburg held a press conference to announce findings of their investigation into possible data fraud on the part of author Stapel.
"[45] The research result, obtained by Stapel and co-workers Roos Vonk and Marcel Zeelenberg, that carnivores are more selfish than vegetarians, which was widely publicized in Dutch media,[48] was suspected and later turned out to be based on falsified data.
I realize that by this behavior I have left my immediate colleagues bewildered and angry and have put my field of study, social psychology, in a bad light.