This study intends to investigate the validity of a self-efficacy measure which is developed for predictive and diagnostic purposes concerning student teachers in competence-based education. CFA results delivered converging evidence for the multidimensionality of the student teacher self-efficacy construct and the bi-factor model as underlying structure, reflecting a teacher competence framework. Factor loadings of the bifactor model evidenced the theoretical assumption that incipient student teachers enter the programme with a global undifferentiated sense of teacher self-efficacy, having teaching experiences a further differentiation takes place to a partly differentiated sense of teacher efficacy. Logistic regression analysis revealed that the measure succeeds in predicting students' first-year outcomes and delivered evidence for the diagnostic value of the scale.