Assessing Well-Being Across Space and Time: Measurement Equivalence of the WHO-5 in 36 European Countries and Over 8 Years

Subjective well-being is a universal and vital element of human flourishing. The WHO-5 is one of the most widely used scales for assessing general well-being and depression. Despite translations in over 30 languages, no comprehensive study has thus far examined the measurement equivalence of the WHO-5 across countries and time. Lack of measurement invariance might occur because of the variation in how people in different societies respond to surveys or differences in the cultural norms surrounding the expression of well-being and emotions. In this study, we relied on three waves of the European Quality of Life Survey ( 2009 , 2014 , 2017a , 2017b ) to determine to what extent the WHO-5 taps the same construct in an equivalent fashion across 36 European countries over an 8-year span. We found evidence for both configural and metric invariance across different conceptualizations of culture and indicators of response styles. Although scalar invariance was not reliably found in multigroup factor analysis, results from alignment optimization revealed adequate approximate invariance across groupings, suggesting that the WHO-5 is applicable for cross-cultural mean comparisons. However, it is debatable if approximate invariance is sufficient to establish a clinical criterion for depression/impaired mental health. We discuss the implications of our results.