The article first presents a brief overview of the principles of effective classification and a summary of the evolution of risk assessments, followed by an explanation of why the AO chose to create its own risk-assessment instrument rather than use an existing instrument. The AO's development of its own risk-assessment tool, the Post Conviction Risk Assessment (PCRA) instrument, stemmed from the Strategic Assessment of the Federal Probation and Pretrial Services System's identification of shortcomings with the AO's use of the Risk Prediction Index (RPI). One of the concerns was the RPI's static nature, which causes a disconnection between the risk score and case management. If an offender's risk to recidivate changes during the course of supervision, the RPI does not reflect this change. This finding motivated the AO to develop its own Research to Result effort. Overall results of the AO's research efforts demonstrated that the PCRA provides adequate predictive validity both in the short term (6-12 months) and in longer follow-up periods (up to 48 months). The PCRA was found to identify and measure dynamic risk factors that - when changed through supervision, services, or some other unmeasured process (natural desistance) - lead to commensurate reductions in actual failure rates. The dynamic nature of the PCRA adds to its usefulness in developing case plans throughout the supervision term. This article provides details on the methods, measures, and samples used in the development of the PCRA. Efforts were supported by a relatively large dataset and fairly complete data. The sample was fairly representative of the population served and allowed for a construction and two validation samples. 6 tables, 1 figure, 39 references, and appended supplementary information