Measuring Physical Function in Community-Dwelling Older Persons
A Comparison of Self-Administered, Interviewer-Administered, and Performance-Based Measures
Published In: Journal of the American Geriatrics Society, v. 43, Jan. 1995, p. 17-23
Posted on RAND.org on December 31, 1994
Compares two self- administered, two interviewer-administered, and one performance-based measure of physical functioning in community-based older persons. All 83 study participants completed by self-administration the Functional Status Questionnaire (FSQ) and the SF-36; by interview, the Katz Activities of Daily Living questionnaire and the Older Americans Resources and Services Instrumental Activities of Daily Living questionnaire; and by direct activity, the Physician Performance Test. Correlations between the FSQ and SF-36 were higher than between the self-administered and interviewer-administered or performance-based measures. Based on a number of correlation comparisons, the authors conclude that relationships among commonly used self- administered, interviewer administered, and performance-based measures of physical function are inconsistent and weak, suggesting that these instruments are not measuring the same construct. It is unclear which instrument is more valid, and the authors suggest that a combination of instruments may produce the best sense of the patient's functioning.