In part, policymakers perceived psychological research as being overly focused on the individual rather than on the larger units of analysis. However, there are methodological and political biases that psychologists often bring to research in corrections, which render the results of minimal use to policymakers. This article explores how the different perspectives of researchers and practitioners affect the conduct of research and its impact on policy. In addition, data are presented which raise questions about the impact of prison crowding on illness, suicide, and death rates. Finally, several recommendations are made for increasing the policy relevance of psychological research, on prison crowding in particular. 1 figure, 1 table, 65 references. (Author abstract modified)