The use of estimation and approximation measures throughout the course of research facilitates the Correctional Service of Canada (CSC) in meeting its operational related endeavors. Specifically, the appropriate application of statistical techniques to fill data gaps enhances the accuracy of population forecast, aiding the decision processes concerned with capital and accommodation planning. CSC assesses offenders’ risk to themselves, other offenders, staff members, and society which is established via professional experiences and judgments, and the use of validated actuarial tools throughout the course of an offender’s sentence. This article reviews research techniques employed for the empirically based contribution to CSC decisionmaking, focusing on procedures of estimation and approximation. The article outlines the techniques of estimation and approximation in: (1) forecasting the Federal offender population and (2) the psychometric examination of actuarial tools that predict static risk. In both cases, empirical techniques are reviewed with respect to their contributions to the CSC’s operational-related endeavors.