The bulletin summarizes findings from Bulletin 3: Prediction and Risk/Needs Assessment, one of a series of papers prepared for the Transitions from Juvenile Delinquency to Adult Crime study group. In order to predict and assess an individual’s risk for criminal behavior, practitioners need to consider risk factors – those factors that increase the likelihood that youth will engage in delinquency, needs factors – risk factors that could be changed in order to reduce the likelihood that youth will engage in delinquency, and protective factors – the characteristics of youth and their circumstances that can protect them from engaging in criminal behavior. The standardized assessment tools that practitioners can use to conduct risk/needs assessments are unstructured clinical assessments, actuarial decisionmaking, static/dynamic actuarial measures, and structured professional judgment. The bulletin also summarizes the results of research comparing 12 standardized assessment tools used for assessing risk in youths and adults. Implications for policy and practice are discussed.