In summarizing a number of classification studies, Andrews, Bonta, and Hoge (1990) propose the following principles of classification: the risk principle (assigning offenders to security levels based on risk of misconduct); the needs principle (determination of the types of services each offender should receive); and the responsivity principle (offender's likelihood of achieving successful outcome from program efforts). The types of commonly used classification systems are risk assessment systems, which assign offenders to institution-based or community-based correctional options on the basis of security criteria; needs assessment system, which identify offenders according to important treatment needs; and psychological systems, which assign individuals to treatment options or living units on the basis of personality or behavioral criteria. An overview of the most recent work in correctional classification shows that the field is moving in two somewhat new directions: increased attention to criminogenic needs and the incorporation of classification items into management information systems or artificial intelligence. Three notes, key concepts and terms as well as discussion questions are provided.