Examining the Psychometric Properties of the Family Affluence Scale in Norwegian Health Behaviour in School-Aged Children Surveys: Implications for Time Trend Analysis

Abstract

This study assessed the applicability of the Family Affluence Scale II (FASII) for conducting time trend analysis within Norway's “Health Behaviour in School-Aged Children Study” (HBSC), spanning from 2002 to 2018. A dataset comprising 27,470 valid questionnaires was employed to assess the psychometric properties of the FASII with respect to validity and reliability for use at single- and multiple times points. The analytical approach encompassed a range of statistical techniques, including confirmatory factor analysis (CFA), multi-group CFA, polychoric correlation testing between FASII scores and perceived family wealth, a subjective measure of socioeconomic position (SEP), and an assessment of perceived family wealth and FASII scores across time. The results of the study revealed an overall good model fit in CFA and a positive correlation between FASII scores and perceived family wealth. However, the analysis uncovered measurement non-invariance across survey years, sex, and age groups. Measurement non-invariance hampers direct time-to-time comparisons of FASII scores, impeding the assessment of affluence development over time. Despite this limitation, FASII maintains its utility for ranking affluence and measuring health outcomes at single time points. As such, this study offers valuable insight into the suitability of FASII for time trend analysis within the Norwegian HBSC data and broader research on social inequality.