Psychometrics

Twenty-four data centers representing 23 countries with 11,830 respondents established the psychometric properties of the WHOQOL-BREF where factor analysis of the 4 domains found that internal consistency was highest for the 7-item physical domain at α = 0.82, followed by the psychological domain at 0.81, the environment domain at 0.80, and lowest for the social domain at 0.68 (Skevington, Lotfy, & O’Connell, 2004). The same cohort determined that the mean scores of the 4 domains were physical at 16.2, psychological at 15.0, environment at 13.5, and social at 14.3) (Skevington et al., 2004). Another study involving data sets of 300 people determined that domain scores produced by the WHOQOL-BREF correlated highly with the original WHOQOL-100 with a range of 0.89 to 0.95 (Harper & Power, 1998). A study among patients with schizophrenia showed excellent internal consistency of α = 0.88 at baseline and 0.89 at 1-year follow-up (Mas-Expósito et al., 2011). Internal consistencies and test–retest coefficients, in a homeless substance-dependent veteran population were above 0.70 for all domains (Garcia-Rea & LePage, 2010). Divergent validity of WHOQOL–BREF showed that domain scores were negatively correlated with the Global Deterioration Scale with coefficients ranging from –0.47 to –0.76 for a Canadian sample of 192 older adults, and –0.46 to –0.59 for a Norwegian sample of 469 older adults. The same study found correlations with the Short Form 12 (an instrument that measures health and functioning status) were also statistically significant with a range from r = 0.24 to 0.78 for the Canadian sample and r = 0.21 to 0.76 for the Norwegian (Kalfoss et al., 2008).