Inter-rater reliability, standard error of measurement and minimal detectable change of the 12-item WHODAS 2.0 and four performance tests in institutionalized ambulatory older adults

AbstractPurpose: Self-reported and performance-based instruments are both necessary for a comprehensive view of the functioning of institutionalized older adults. Our aim was to assess the reliability and measurement error of the 12-item World Health Organization Disability assessment Schedule and compare these indexes against performance-based tests.Materials and methods: One hundred participants from Nursing Homes and Day Care Centers were assessed twice (two days to one week apart) by two independent assessors. Reliability and measurement error indexes were calculated.Results: Reliability of the World Health Organization Disability assessment Schedule total score, and of three performance tests was appropriate for individual comparisons (ICC ≥ 0.92). Reliability for the five times seat to stand test was appropriate for group comparisons only (ICC = 0.84). The high measurement error of the timed up and go test (SEM = 4.25; MDC = 11.78) and of the five times seat to stand test (SEM = 3.47; MDC = 9.62) an...