The psychometric properties of a short version of the General Self-Efficacy Scale: A Rasch analysis

Abstract Background Self-efficacy is important in adolescence and is found to affect adolescents’ physical activity, risk-taking behaviour and health decisions. Self-efficacy describes a person’s belief in own coping abilities. Having good measures of self-efficacy may contribute to more valid knowledge about the potential role of self-efficacy as a health promoting factor in adolescents lives. Several scales measuring self-efficacy exists. One of these is the General Self-Efficacy Scale comprising 10-items. However, there exists several short versions of the scale. In a large cross-sectional study among adolescents in secondary schools in Norway, five of the items from the General Self-Efficacy Scale are used. The aim of this study is to examine the psychometric properties of this short version of the General Self-Efficacy Scale applying Rasch measurement theory. Methods This study is based on cross-sectional data from the Youth Data Survey. The data collection was carried out in lower and upper secondary schools in Norway during 2018. In total, 6646 adolescents responded to a web-based questionnaire. The data were analysed using the partial credit parameterization of the unidimensional Rasch model. Results Preliminary results indicated that the short version had acceptable reliability (person separation index: 0.78). However, the targeting could have been better (mean person location: 1.441). All items had ordered thresholds. One under-discriminating item and three over-discriminating items were identified. Three items displayed differential item functioning with regard to gender and one item displayed differential item functioning for school level. Conclusions Based on our preliminary findings this short version of the General Self-Efficacy Scale has the potential to measure self-efficacy among adolescents, but there are room for improvements. The scale has some shortcomings related to targeting and differential item functioning that needs to be further explored. Key messages The short version of the General Self-Efficacy Scale has the potential to measure self-efficacy in adolescents. The scale has some shortcomings that needs to be further judged.