The Bergen Shopping Addiction Scale (BSAS): factor structure, longitudinal measurement invariance, and temporal stability across a two-year interval

Abstract The Bergen Shopping Addiction Scale (BSAS; Andreassen et al., 2015) is a theory driven self-rating questionnaire for assessing shopping addiction. The current study employed Confirmatory Factor Analysis to examine its factor structure, and its longitudinal measurement invariance among adult participants (N = 276) aged 18 to 62 years (mean = 31.86 years; SD = 9.94 years) over a two-year period, with assessments conducted at three time points. Overall, there was support for full measurement invariance (configural, metric, scalar, and error variance invariance). Additionally, there was support for temporal stability and equivalency for the BSAS total mean scores across the three time points. The psychometric and practical implications of the findings are discussed.