The impact of three sociodemographic, two cognitive, two affective, and four personality measures on the discrepancies between self-reported and performance-based ADL in a sample of 753 frail elderly is studied by means of multiple regression analyses. Underestimation (i.e., lower self-reported levels of ADL compared to performance-based levels) occurs, in particular, among subjects with low perceptions of physical competence and mastery or personal control, and high levels of depressive symptomatology. In contrast, the role of cognitive functioning and sociodemographic variables in the discrepancies is a minor one. Although self-report ADL measures are easier to administer and less sensitive to nonresponse than performance-based ADL measures, the confounding effects of perceived physical competence, mastery, and depressive symptomatology on self-reported ADL should be considered in any application of self-report measures of ADL among frail elderly.
