In response to a mandate imposed by the County Community Mental Health Board, a psychosocial rehabilitation agency proposed that its consumer group would develop their own functional level scale to measure effectiveness of the services provided. The paper describes the development of the scale and the procedures used to examine its reliability and validity. The findings suggest that the Community Living Skills Scale developed by the Client Oriented Program Evaluation (COPE) group taps all relevant areas in regard to functional levels of the chronically mentally ill in the community and that its reliability is high.