This is a work on "hostile" data and the conditions under which they are accepted and rejected. What is the place of data in politics and organization? Why are politicians and administrators so often hostile to research data, or why do they tend to perceive data as hostile to them? How can data become relevant to policy? These questions are the focus of this book. In answer I try to show how political and administrative institutions cope with "hostile" data; how they seek to maintain closedness to disconfirming data, and how they are led, in a free society, to change their policies despite the epistemological bias in favor of the already known and the initial inclination to resist change. At the same time, I demonstrate that data producers must learn that while their research findings may be subjected to science's own standards of verifiability, such data must also meet standards of contestability by the various interests involved in political and administrative decisions. The production and "appropriate" publication of a research report may at best buy one an admission ticket to participate in political and administrative contests, but not the power nor the justification to determine the outcomes of the contest. I begin with two hypotheses: Hypothesis 1: Politicians or administrators reject data that do not coincide with behavior they are unwilling to change. Hypothesis II: Politicians or administrators change behavior that does not coincide with data they are unwilling to reject.