The main goal of EBP is to place high-risk offenders into appropriately intensive treatment services that are reserved for offenders with the highest risk of reoffending. The author begins by discussing the differences between risk and needs. Risk refers to the likelihood than an offender will reoffend while needs refers to factors that should be addressed to reduce the risk of reoffending. The use of standardized risk and needs assessment tools to predict an offenders’ likelihood of reoffending is discussed as a necessary safeguard against biased or inappropriate subjective assessments made by professionals. As the use of standardized assessment measures grew in the field of corrections there was a need to combine risk and needs assessments into one instrument or protocol that could (1) determine the degree to which an offender’s history predicted their likely risk and (2) identify the needs or psychosocial factors that should be addressed to reduce risk of reoffending. The authors review actuarial risk factors, which generally refer to demographic or historical factors that predispose the individual to offending behavior, and dynamic risk factors, which are psychosocial needs that should be addressed in order to decrease the risk of reoffending. Criminal drivers or needs tend to fall in several areas--substance abuse, family dysfunction, peer associates, criminal personality, antisocial thinking or attitudes, low self control, mental health, self-esteem, low educational attainment, and employment--each of which is discussed. Criminal justice agencies are encouraged to use standardized risk and needs assessment instruments to identify and address the criminal drivers of high-risk offenders. Tables, exhibit, references