Abstract
BACKGROUND: Most measures of quality of life (QoL) are based on 'expert' opinions. This study describes a new measure of QoL in older age, the Older People's QoL Questionnaire (OPQOL), which is unique in being derived from the views of lay people, cross-checked against theoretical models for assessment of comprehensiveness. Its performance was assessed cross-sectionally and longitudinally. It was compared with two existing QoL measures in the cross-sectional studies in order to identify the optimal measure for use with older populations. METHODS: Data were taken from three surveys of older people living at home in Britain in 2007-2008: one population survey of people aged 65+, one focused enumeration survey of ethnically diverse older people aged 65+, one follow-up of a population survey of people aged 65+ at baseline in 1999/2000. Measures were QoL (using OPQOL, Control, Autonomy, Satisfaction, Pleasure--19 items (CASP-19), World Health Organization Quality of Life questionnaire--version for older people (WHOQOL-OLD)), health, social and socioeconomic circumstances. The CASP-19 and WHOQOL-OLD were not administered to the longitudinal sample in order to reduce respondent burden. RESULTS: Psychometric tests were applied to each QoL measure. The OPQOL, CASP-19 and WHOQOL-OLD performed well with the cross-sectional samples; however, only the OPQOL met criteria for internal consistency in the Ethnibus samples. CONCLUSION: The OPQOL is of potential value in the outcome assessment of health and social interventions, which can have a multidimensional impact on people's lives. Further research is needed to examine whether differences by ethnicity reflect real differences in QoL, methodological issues, variations in expectations or cultural differences in reporting.