A Suitable screening to assess self-efficacy in clinical routine and studies? Psychometric properties of the short-form Generalized self-efficacy scale (GSE-6) in rehabilitation

Introduction/Background Self-efficacy plays a key role in explaining and predicting health behavior (e.g. physical activity, nutrition, substance consumption) which are addressed in multimodal rehabilitation. The 10-item General Self-Efficacy Scale (GSE) is a widely used instrument to assess self-efficacy (Schwarzer, 1995). For economic reasons, it is not always possible to apply the GSE. Therefore, this work aims to determine psychometric properties of the recently introduced short form GSE-6 (Romppel, 2013) in rehabilitation patients. Material and method GSE and other relevant impairments and resources were assessed by postal mail in a nationwide study in Germany in 2530 patients aged 20 to 65 years prior to rehabilitation (Brunger, 2017). Psychometric properties were calculated by comparing the short and original version (GSE-6/GSE). The concurrent validity is reported with Spearman correlations to other impairments and resources. Confirmatory factor analyses (CFA) demonstrate the factorial validity. Results Distribution and mean sum scores of both scales were comparable. Soil and ceiling effects were low ( Fig. 1 ). The mean discriminatory power ( r ix  = 0.70/ r ix  = 0.74) and internal consistency were similar ( α  = 0.89/ α  = 0.93). GSE-6/GSE were correlated with r s  = 0.98 ( Fig. 2 ). The correlations of GSE–6/GSE to other impairments and resources were almost identical ( Fig. 3 ). Stratified analyzes by gender and diagnosis groups provided analogous results. Multigroup CFA confirmed the one-dimensional structure of both scales independently of gender, age and diagnosis group. Conclusion Psychometric properties of GSE-6 and GSE were comparably good. Thus, an application of the short version in rehabilitation across all major diagnosis groups seems possible without relevant losses compared to the original version. It allows for a significant reduction in time and may facilitate the assessment of self-efficacy for screening purposes in clinical routine and studies.