Measurement invariance of the Satisfaction with Life Scale: reviewing three decades of research

The Satisfaction with Life Scale (SWLS) is a widely used measure of life satisfaction, a key aspect in quality of life. The SWLS has been used across many socio-demographic groups. Comparison of life satisfaction across different subgroups (e.g., cultures) is meaningful to researchers; such cross-group comparison presupposes that validity of the inferences from SWLS scores holds across various subgroups (measurement invariance: MI). The aim of the present review was to identify, summarize, and evaluate research testing measurement invariance of the SWLS. A targeted literature search identified articles (published 1985-2016) that examined MI of the SWLS using multi-group confirmatory factor analysis. The search retrieved 27 articles, representing 66,380 respondents across 24 nations. Gender, age, and culture were the most common types of MI assessed. Most articles used translated (non-English) versions of the SWLS. The highest level of MI tested in each article (i.e., configural, metric, scalar, strict) varied. Findings generally supported a unidimensional structure (configural MI), but less commonly supported were equivalent factor loadings (metric MI). Over half of the gender invariance analyses supported scalar or strict MI, whereas scalar or strict MI was supported in only 1 of the 11 culture MI analyses and 1 of the 9 age MI analyses. Findings suggest meaningful comparisons of SWLS means across gender may be valid in some situations, but most likely not across culture or age groups. Participants mostly ascribe similar meaning to like items on the SWLS regardless of their gender, but age and especially culture seem to influence this process.