The three most popular inmate classification schemes are risk assessment, which ranks inmates according to their probabilities of posing security problems; the Megargee Minnesota Multiphasic Personality Inventory typology, which categorizes inmates into 1 of 10 personality types; and Toch's Prison Preference Inventory, which focuses on inmates' needs and concerns. Each system has particular strengths and weaknesses, but no one system meets the requirements of a complete classification system. The testing of a model of inmate incarceration adjustment determined that individual, organizational, and interaction effects were most important in determining incarceration adjustment. Thirteen 'two-way' classification schemes (focus on the interaction of individual and organizational variables) were identified by the researchers as potentially useful in reducing the number of inmate adjustment problems. Assessments of the schemes determined that such systems can maximize institutional security and control while minimizing deterioration in inmate functioning. 35 references, 34 data tables, 1 figure, and appended study instruments and methodological discussions.