Longitudinal invariance analysis of the satisfaction with life scale

This research examined longitudinal measurement invariance in the satisfaction with life scale using two studies. The first followed a sample of 236 university students (93 male and 143 female) who completed the SWLS twice over a two-month interval. The second used a sample of 242 adolescent athletes (133 male and 109 female) who completed the SWLS three times over a period of six months. Confirmatory factor analysis was used to examine longitudinal measurement invariance. For the university student sample, results showed that the SWLS is partial strict invariant (equality of factor patterns, loadings and intercepts across time for all items and equality of item uniqueness for Items 1, 2, 4 and 5 across time). For the adolescent athlete student sample, the SWLS is partial strong invariant (equality of factor patterns, loadings across time for all items and equality of intercepts for Items 2, 3, and 4 across time). For both samples, stability coefficients across time were moderately high and latent factor means were not significantly different across time. Generally, these results suggest that the SWLS has satisfactory psychometric properties for longitudinal measurement invariance.