Concurrence between subject and proxy ratings of quality of life for people with and without intellectual disabilities

Abstract

The purpose of this investigation was to examine concurrence between subjects' self-reported quality of life (QOL) and assessments of their QOL made by proxies who were either a first degree relative, or were acting in a supportive role similar to that of a family member. Two studies were conducted. The first study, using ComQol-A4 (Cummins, 1993), examined the degree of concurrence between nondisabled subjects' QOL and ratings made on their behalf by proxies who were either a parent or a sibling (N = 78 subject/proxy pairs). The second study utilised ComQol-ID4 (Cummins, 1993), and examined agreement between QOL ratings made by subjects with mild intellectual disability and proxies who were either parents or support workers (N = 24 subject/proxy pairs). In both studies the effects on agreement of variables including subject/proxy living arrangements, gender similarity, and proxy gender and empathy were examined. In contrast to previous research utilising non-standardised approaches to QOL assessment, results from both studies indicated overall a high degree of subject/proxy concurrence. Overestimation or underestimation of ratings by proxies was minimal. These findings endorse the use of standardised approaches such as ComQol for proxy-based measures of QOL. Also, none of the factors investigated directly affected agreement between subject/proxy QOL reports. If standardised approaches to QOL are employed, and if proxies are selected on the basis of close and regular contact, it does not seem to matter if they are male or female, cohabiting family members or non-cohabiting support workers.