The accuracy of self and informant ratings of physical functional capacity in the elderly.

To compare the accuracy of self-ratings with informant-ratings of physical functional capacity in the elderly, 150 elderly patients attending a geriatric day hospital (GDH) and their formal and informal community carers were administered a questionnaire about their ability to perform activities of daily living (ADL). Direct observation of the patients' performance by therapists at the GDH was used as a standard, after the reliability and validity of this approach had been evaluated. Self-ratings were shown to be more accurate and less biased than informant-ratings, both for individual ADL and overall functional capacity. The accuracy of all ratings tended to be greater for less complex or physically demanding ADL, and informants tended to consistently underestimate functional capacity. The concurrent validity of the adapted Barthel Index in a self-report format was also demonstrated. Wherever possible, information concerning the physical functional capacity of an elderly subject should in the first instance be sought from the subject himself, as the quality of such information may be superior to that of his carers.