Around 2% of the investigators admit to have falsified or fabricated data at least once. Also, 34% report to have been guilty to one or more questionable research practices, such as doing many statistical analyses and to publish only what fits their theoretical framework. Prevention of questionable research practices is very important. Universities should ensure that the training is in order and the research culture is adequate, and they should critically look at perverse incentives, such as a too high publication pressure, but also by ensuring proper guidelines, and by having a fair and transparent procedure for suspected violations of scientific integrity. This article is based on my inaugural lecture (in Dutch) formally starting my chair on Methodology and Integrity, which was presented at VU University Amsterdam on May 2, 2014. The Dutch version of the lecture was distributed as a booklet among the audience and is submitted for publication to the Dutch and Flemish journal for management in higher education Thema. The original Dutch text and the English translation of the inaugural lecture were made available as PDF in the repository of VU University Amsterdam.