A psychometric evaluation of the Satisfaction with Life Scale in a Swedish nationwide sample of university students

The Satisfaction With Life Scale (SWLS) is an established measure of life satisfaction, a concept central to the research area of subjective well-being. The purpose of the present study was to test the psychometric properties of the SWLS using confirmatory factor analysis, including tests of measurement invariance across sex and age. A nationwide cross-sectional study was performed based on the data of 2900 Swedish student teachers. A unidimensional measurement model of the SWLS was tested and received empirical support. The results further indicate that the SWLS is invariant across sex but not across age. When scrutinizing the local fit of the model, the results indicate that item 4 and item 5 are sensitive to age and that these items may need to be rephrased. The modification indices of the model suggested an alternation of the factor structure. Hence a theoretically supported, two-factor second-order measurement model was tested. The two-factor second-order model had a superior fit compared to the unidimensional model, suggesting that the factor structure of the SWLS may have to be reconsidered. The study both expands and adds support to the existing body of life satisfaction literature.