This study was designed to examine the accuracy of patient self-report of physical activity and social behavior and a 3X daily log of pain intensity. Concomitantly, staff members made unobtrusive, hourly observations of patient activity and social behavior. Results showed that some patients report significantly lower levels of physical activity and social behavior than observed by staff despite reporting decreased levels of pain. These results suggest that the efficacy of therapeutic intervention is best determined by systematic observational data rather than patient self-report.