A comparative assessment of the viability of five psychological systems for classifying offender populations was undertaken: Megargee's Minnesota Multiphasic Inventory-Based Criminal Classification System, Interpersonal Maturity Level (I-level), Quay's Adult Internal Management System, the Jesness Inventory Classification System, and Conceptual Level. Integrating the findings of the predictive analyses with those of the construct validity analysis provides the basis for recommending provision for the following offenders in medium-security to maximum-security settings: committed criminal, immature dependent, character disordered, situational, neurotic, and disturbed. All but the committed criminal type should be important considerations in minimum-security settings. Long, inefficient procedures do not emerge as superior to the shorter assessments in terms of reliability or construct and predictive validity. 36 notes, 4 figures, 51 tables, 5 appendixes, and 141 references