Regarding a theoretical model for correctional treatment programs, social learning theory has been successfully applied in correctional settings. In its simplest form, this theory holds that behaviors are learned and repeated when rewards for the actor are attached to the behavior. Another effective mechanism through which behavior is learned is through modeling the behaviors that are being taught. Given a proven theoretical background it is possible to design and develop effective correctional programs. In the area of assessment and treatment delivery for offenders, Don Andrews has argued that there are four basic principles to take into account: risk, need, responsivity, and professional discretion. Each of these principles is explained in this paper. In determining whether specific types of treatment programs have the desired effect on offender behavior, evaluation research and the meta analysis of multiple evaluations have contributed to this effort. Evaluation research has not only proven the effectiveness of various treatment methods in producing positive change in offender behavior and attitudes, but has also led to the identification and replication of program elements associated with particular desired changes. Overall, the research reviewed indicates that programs which target factors linked to criminal behavior should be the targets for change in correctional programming. Substance abuse is one of the most important factors related to criminal behavior. In the course of addressing these factors, program delivery should take into account offenders' learning needs, including cultural conditioning and values. The application of the risk/need responsivity principles will contribute to program effectiveness and efficiency. 5 tables and 16 references