Factors affecting contrasting results between self-reported and performance-based levels of physical limitation.

We have examined the role of socio-demographic variables, cognitive and affective functioning, and personality in discrepancies between performance-based and self-report measures within three domains of physical limitations: motor functioning, hearing and vision. Data are drawn from a community-based sample of 624 persons of 57 years of age and older. The strength of the association between self-reported and performance-based levels of physical limitations is moderate. Socio-demographic variables and levels of cognitive functioning explained some of the discrepancies between self-reported and performance-based vision. Within the domains of motor functioning and hearing, discrepancies were substantially influenced by affective functioning and personality. The discrepancies may reflect bias in perception or true variation in the effect of limitations on daily functioning. Both self-report and performance-based measures seem to complement each other in providing useful information about physical limitations.