Measurement of quality of life for people who may not be able to verbally express their feelings remains a major challenge for providers of services to people with learning disabilities. Scores from self-reports of people with learning disabilities able to respond to questionnaires do not always match scores obtained from family members or support staff.
The authors of this article report on two studies which aimed to evaluate the impact on quality of life scores of self-report vs. proxy ratings.
The researchers used the Personal Outcomes Scale, both the self-report version and the direct observation version. When they used the direct observation form they asked direct support staff and family members to be the respondents.
The first study evaluated consistency between self-report and direct observation data using support staff as proxy respondents. In this study they found that there were significant mean differences between the two respondent groups in three quality of life domains, although there was an acceptable level of internal consistency for self-report and direct observation strategies.
The second study looked at the difference between client self-report and proxy ratings made relating to the same individual client which used direct observation interviews with family and support staff. This study found some differences between client and staff ratings but no significant differences between client and family ratings.
They conclude that from these findings, there continues to be a need for “methodological pluralism in quality of life assessment” suggesting continued focus on the importance of self-report but also the need to develop better and “more reliably user-friendly strategies to evaluate quality of life outcomes for those individuals who either do not or cannot respond for themselves.”
Relationship between Self-Report and Proxy Ratings on Assessed Personal Quality of Life-Related Outcomes, Claes C et al., in Journal of Policy and Practice in Intellectual Disabilities, 9: 159–165.