The World Health Organization Quality of Life Scale (WHOQOL-BREF) is predicated on a multidimensional perspective on quality of life (QOL); yet studies are unclear about the latent structure underlying responses. This article reports on a study conducted to investigate the structure of WHOQOL-BREF scores. Competing latent structures of the data were examined in a general population sample. In addition, the complete factorial invariance of the retained model was investigated across gender. We also investigated latent mean differences in the QOL dimensions over age as well as age by gender interactions effects. Based on responses to the WHOQOL-BREF, support was found for a bifactor exploratory structural equation modeling representation of the data. This measurement structure accounts for construct-relevant multidimensionality in item responses due to the presence of general and specific factors underlying the data and the fallibility of indictors as pure reflections of only the single constructs they are purported to measure. Furthermore, support was found for measurement and structural invariance across gender. Finally, evidence was obtained for a curvilinear relationship of age with QOL, characterized by a midlife nadir. Taken together, the results of the study yield important validation data for the WHOQOL-BREF and tentatively resolve the dimensionality issues in the measurement of QOL using this instrument.
Keywords: ESEM; QOL; bifactor models; dimensionality.