The current paper reports on the feasibility of using the HAPI-A, an instrument designed to assess a person's level of functioning in the community: (1) to help determine eligibility to receive behavioral health services, (2) to assign reimbursement case rates; and (3) to provide data for a service provider report card. A 3-year field study of the use of the instrument across an entire state mental health system explored the effectiveness of methods to enhance data accuracy, including annual training and a professional clinical record audit, and the ability of the test to detect differences in improvement rates within risk-adjusted groupings. The combination of training and auditing produced statistically significant, cumulative reductions in data errors across all 3 years of the field test. The HAPI-A also was sensitive in detecting differences among service providers in outcome improvements for six of six risk-adjusted groups rated at the moderate level of impairment and for five of six groups rated at the mild level of impairment, but was inconsistent in detecting outcome differences for persons rated at the severe level of impairment.