The MRAS applies seven principles derived from recent developments in decision theory, public health, and a methodological audit of existing studies. First, "dangerousness" must be disaggregated into its component parts: the variables used to predict violence (risk factors), the amount and type of violence being predicted (harm), and the likelihood that harm will occur (risk). Second, a rich array of theoretically chosen risk factors in multiple domains must be chosen; and third, harm must be scaled in terms of seriousness and assessed with multiple measures. Fourth, risk must be treated as a probability estimate that changes over time and context; and fifth, priority must be given to actuarial research that establishes a relationship between risk factors and harm. Sixth, large and broadly representative samples of patients at multiple, coordinated sites must participate in the research. Finally, managing risk as well as assessing risk must be a goal of the research. In describing how these seven principles are being implemented in the MRAS, this chapter presents the results of the field trials that preceded full-scale research implementation and details the implications of these results for the final study design. 5 tables and 34 references