Validity and reliability of the Medical Outcomes Study Short Form-20 questionnaire as a measure of quality of life in elderly people living at home

Abstract

Background: the Medical Outcomes Study Short Form-20 (SF-20) questionnaire is recommended for health-related quality of life research, but there is little information on its utility in older people. We assessed the validity, reliability and feasibility of using the SF-20 in an elderly community-dwelling population. Methods: the SF-20 was administered to a stratified, random sample of 333 elderly subjects. Findings: assessment of content validity revealed that important domains were lacking, while others appeared to be inappropriately combined. Using Spearman correlation coefficients, the SF-20 had acceptable convergent and discriminant validity. A principal components analysis provided evidence for internal consistency for some of the subscales. Evidence for test-retest reliability was good. Interpretation: while the reliability and feasibility of the SF-20 appear satisfactory, concerns about validity and responsiveness should temper enthusiasm for its use with elderly people living at home.