The Arthritis Impact Measurement Scales (AIMS) have been developed to assess the health status of arthritis patients. In this study, the self-administered AIMS questionnaire, which includes scales designed to measure the physical, psychologic, and social aspects of health status, was completed by 625 patients with various forms of arthritis. A comprehensive battery of analytic techniques was used to investigate the performance of these scales in this large sample. The results confirmed the reliability and validity of the AIMS instrument. They also showed that AIMS performs well in at least 4 major types of arthritis, in a range of sociodemographic groups, and across time. These findings emphasize the strengths of the AIMS approach and suggest that the instrument will prove useful as a tool to assess arthritis outcome in a wide variety of clinical settings.