Policymakers, practitioners, and researchers rely heavily on risk assessment tools as a way to direct resources and support recidivism reduction strategies. Risk Assessment Instruments Validated and Implemented in Correctional Settings in the United States: An Empirical Guide is a report designed to provide foundational knowledge and a working framework of risk assessment instruments for criminal justice and social service agencies, practitioners, and policymakers. Though variability exists across risk instruments and assessment procedures, these tools perform a critical role in helping correctional staff develop case plans informed by individual risk and need. As a practical guide, the report outlines the components and parameters of risk assessment instruments validated and implemented in correctional settings in the United States, provides a review of and catalogues the available knowledge regarding the accuracy and predictive validity of risk assessment instruments for adult offenders, and presents steps that might be taken to improve public safety outcomes associated with the implementation of criminal justice risk assessment tools. Reentry strategies that incorporate case management plans based on valid assessments have the potential to reduce recidivism.