To determine the concordance of 4 methods of disability assessment with the criterion method. Performance testing in the home was selected as the criterion.
The task performance of 57 community-dwelling older women (>/=70 years) with knee osteoarthritis was examined through self report, proxy report, clinical judgment based on impairment measures, performance testing in an occupational therapy clinic, and performance testing in participants' homes. The 26 tasks represented 4 domains of daily living activities: 5 functional mobility, 3 personal care, 14 cognitively oriented instrumental activities of daily living (IADL), and 4 physically oriented IADL.
In general, self reports and proxy reports had the highest concordance with in-home performance test results. Nonetheless, even for these methods, depending on task domain, the rate of discordance ranged from 31% to 54%, being least in personal care and greatest in the physically oriented IADL.
Disability estimates based on self reports, proxy reports, clinical judgments, and hospital performance-based assessments are not interchangeable with in-home task performance.