Its full value not only as a tool for assigning clients to an appropriate setting, but also as a management tool for assessing program efficacy is recognized by correctional administrators all over the world. Methods for determining the kinds of inmates that come into a system are based on such factors as age at first adjudication, seriousness of the first offense, number of prior incarcerations, drug or alcohol abuse, emotional instability, number of previous escape attempts, and number of prison infractions. A reliable assessment of an inmate's custodial needs is simple to provide using instruments such as the Minnesota Multiphasic Psychological Inventory or the California Personality Inventory. The assessment of correctional programs, however, is more difficult because the style of correctional officers and the actual focus of an institution, whether rehabilitative or custodial, are still largely ignored. Five general inmate types have been identified: (1) overly aggressive, hostile to authority, prone to disciplinary infractions, and predatory; (2) nonconfrontational, manipulative, untrustworthy, prone to disciplinary infractions, hostile to authority, and predatory; (3) reliable, cooperative, noncriminal in outlook, concerned for others, and not prone to disciplinary infractions; (4) dependent, unreliable, passive, scapegoated, victimized, and not prone to infractions; and (5) anxious, afraid, explosive under stress, victimized, and somewhat prone to infractions. The use of statistical techniques to characterize and classify inmates is considered as well as reclassification, accountability, flaws in classification, and the use of computer hardware software and hardware in offender classification and reclassification. 28 references and 1 figure