Reliability and validity of the Norwegian WHOQOL-OLD module.

The aim of this study was to examine the validity and reliability of the Norwegian WHOQOL-OLD six-facet, 24-item module designed for assessing generic quality of life cross-culturally among the elderly. Using quota-stratified sampling defined on the basis of sex, age and geographical representation, 401 respondents were drawn from Statistics Norway and completed postal surveys. An additional 89 elderly completed personal interviews. Correlation and multivariate analyses partly confirmed the relevance of individual items and facets in both groups. All items correlated significantly higher with their original facets, although almost half of these items correlated with other facets in both groups. Multiple regression analysis of the module and two overall questions (dependent variables) showed that three facets made significant contributions to overall health, with Social Participation (B = 0.09) contributing most strongly in the postal-group. In the interview-group, only Social Participation (B = 0.20) was found to make a significant contribution, and this was in relation to overall health satisfaction. When the WHOQOL-BREF total score was considered as the dependent variable, different facets contributed significantly in both groups. Exploratory factor analysis of the WHOQOL-OLD in the combined group of both postal and interview samples, resulted in a five-factor solution (eigenvalues >1) explaining 65% of the cumulative variance in five of the six originally operationalized facets. The most conceptually clear facets were Death and Dying and Sensory Abilities. Further, confirmatory factor analyses in the combined group demonstrated a model with good fit, but with high covariance between the factors. Acceptable internal consistency was shown except for the Past, Present and Future Activities in both groups. Since construct validity was only partially confirmed, exploration of the scale's conceptual validity needs further testing in Norwegian and international samples.