On January 20, 1999, Dr. Hans de Kwaadsteniet, a senior statistician at the Netherlands National Institute for Public Health and the Environment (Rijksinstituut voor Volksgezondheid en Milieu, RIVM), made news in the Netherlands. After years of trying to convince his superiors that the environmental assessment branch (Netherlands Environmental Assessment Agency)* of the institute leaned too much toward computer simulation at the expense of measurements, he went public with this criticism by publishing an article on the op-ed page of the national newspaper, Trouw (de Kwaadsteniet 1999). His article was supplemented with an interview that resulted in the headline ‘Environmental Institute Lies and Deceives’ on the newspaper’s front page. His specic claim was that the institute suggested too high an accuracy of the environmental gures published yearly in its State of the Environment report. According to him, too many model results that had not been rigorously compared with observational data were included-mostly because of the lack of sufciently detailed data with which to do the necessary comparisons. He pointed out that living in an ‘imaginary world’ was dangerous. He thought that if the institute spent more time and energy on testing and developing computer-simulation models in a way that made greater use of existing and newly performed observations, it would become more careful in the way it presented its results to policymakers. De Kwaadsteniet identied the deceptive speed, clarity, and internal consistency of the computer-simulation approach as the main causes of the claimed bias toward computer simulation at the RIVM’s environmental assessment branch.