An Incomplete Model of Disability: Discrepancies Between Performance-Based and Self-Reported Measures of Functioning

Background: Appropriate conceptualization and measurement of disability are critical for population-focused resource allocation and policy development. Self-reported and performance-based measures of functioning have been used to represent disability. Variation in environmental context or self-perception of ability may influence self-reports; however, performance-based measures that attempt to control environmental context may not accurately capture real-world aspects of functioning. This study examined the agreement between self-report and performance-based measures of functioning within 4 domains among older adults. Methods: Cross-sectional data from the 2021 National Health and Aging Trends Study was used. Self-reported and performance-based measures of functioning were assessed for vision, hearing, mobility, and memory domains. We examined the diagnostic characteristics of performance-based versus self-reported measures using sensitivity, specificity, and receiver operating characteristics curves. Differences in the agreement of these measures across sociodemographic groups were investigated using logistic regression. Results: Among 2 442 respondents 71 years and older (mean 78.5 ± 5.3, 56% female participants), performance measures of hearing and mobility had high sensitivity (89% and 91%, respectively) and low/moderate specificity (36% and 63%, respectively). The sensitivity and specificity of vision measures were 71%. Memory measures had high specificity (89%) and low sensitivity (28%). Performance-based discrimination ranged from 0.59 (memory) to 0.78 (mobility). Agreement varied across sociodemographic factors. Conclusions: Performance measures diverge from self-reported functioning among older adults. Discordance may reveal opportunities for environmental intervention where participants' performance does not capture the full extent of barriers in their daily lives. Additional research is needed to investigate individual and environmental factors which could explain the observed differences.