To facilitate and standardize inmate classification on a national level and to address court mandates, the American Correctional Association has established a set of standards for classification. Classification (prediction) procedures are of three types: anamnestic, which are based solely on an individual’s past behavior; clinical, which are based on expert diagnosis and evaluation; and statistical or actuarial, which are based on individual behavior patterns in comparison with similar behavior patterns of others. The problems of criminal prediction include the false positive and false negative predictions, the complexity of predicting human behavior, and depriving individuals of their liberty and access to goods and services. Classification of prisoners is the differential assignment of people to varying levels of security: maximum, close, medium, and minimum. The determination of custody level is influenced primarily by the risk that the prisoner presents to the safe and orderly operation of an institution. Custody classification is related to security classification, and the classification level affects an inmate’s access to various counseling, educational, vocational, and recreational programs. Program access varies inversely with security and with custody levels, as security is increased, program access is decreased. Modern classification procedures have been influenced by the judiciary and by the various human sciences. Various testing and assessment tools have been developed, which can be used by correctional administrators to evaluate inmates in terms of their personalities, needs, and potentialities. These include the General Aptitude Test Battery (GATB), Wechsler IQ (WAIS), Minnesota Multiphasic Personality Inventory (MMPI), Human Synergistics Lifestyles Inventory (HSLI), and Myers-Briggs Type Indicator (MBTI). Most classification methods used are hybrids of the National Institute of Corrections’ Model for Custody and Need (NIC) and the Adult Internal Management System (AIMS). The issues they address are the risk that an inmate presents to society and the institution, and the needs of the inmate to minimize that risk. 26 references, 5 figures