The authors used comparative rates of slate hospitalization to measure the effect of their mental health/mental retardation center. Census tracts from their catchment area were matched with census tracts from an area that does not have such a center but that is served by the same state hospital. Lower rates of admissions to the state hospital and decreased chronic hospitalization were found in the catchment area population, and the center's activities were found to be related to these changes.Abstract Teaser