The Investigation of Psychometric Properties (Validity and Reliability Reassessment) of WHO QOL-BREF Questionnaire in Shahrekord Cohort Study

Abstract

Background and aims: The purpose of this study was to revalidate the Persian version of the WHOquality of life (WHOQOL-BREF) instrument to determine the quality of life status in the ShahrekordCohort Study (SCS) in the southwest of Iran. This study was designed to serve as one of the sources ofthe Prospective Epidemiological Research Studies in Iran.Materials and Methods: In this cross-sectional study, 2000 people were randomly selected from thestudy population of the SCS. The reliability and internal consistency of the WHOQOL-BREF weremeasured using Cronbach alpha coefficient and Pearson’s correlation. construct validity and factorsmeasured using Pearson’s correlation matrices with each of its domains. To measure the face, content,and construct validities, the views of the panel of experts and exploratory factor analysis were used. Inaddition, the validity of the questionnaire was evaluated using linear regression.Results: All domains of the questionnaire met the minimum reliability standards (Cronbach alphaand intra-class correlation >0.7), except for social relationships. The results of comparison analysisindicated that the questionnaire discriminated well between subgroups of the study samples differingin their health status. Regarding validity, the Kaiser-Meyer-Olkin (KMO) value was 0.94 and the valueof Bartlett’s test was 1699.01 (P≤0.001).Conclusion: The findings suggested that WHOQOL-BREF is a reliable and valid measure of healthrelatedquality of life among SCS population.