The authors describe uses for a 17-item instrument that efficiently measures the functioning level of chronically mentally ill persons living in the community. The Multnomah Community Ability Scale is designed to be completed by case managers who work with chronically mentally ill consumers. The instrument is sensitive to differences among individuals within this special population of consumers and is easy to complete. Community mental health program staff can be trained to use the scale reliably. The scale has been used to compare levels of severity between urban and rural community mental health program clients. The authors discuss the application of the Multnomah Community Ability Scale to a capitated payment system for severely mentally ill, involuntary clients.