The management classification system was introduced in May 1977. It placed in three separate dormitory units inmates classified according to the following categories: (1) those deemed most likely to act aggressively (predators), (2) those likely to be acted against (victims), and (3) those not belonging to either extreme (average). One dormitory housed all the predators plus some in the average group, while a second dormitory received all the 'victims' plus some in the average group. The third dormitory housed men only from the average group. Inmates were classified according to their scores on the Minnesota Multiphasic Personality Inventory. Except for the introduction of the management classification system, FCI's mission and programs, along with staff and population, remained essentially unchanged immediately before and after introduction of the system. This made possible an evalaution that compared incidents of inmate violent behavior before and after the system's use. Results showed that 1 year after the system began operating, the general rate of violence within the institution had decreased significantly. The level of violence also stayed at the reduced level after the second year. Thus, this system could be applied to other similar settings. Tabular data and 11 references are provided.