How robust is the measure of teacher academic optimism? Evidence on structure, reliability, and measurement invariance in the Serbian primary school context

Since understanding teachers’ beliefs and motivation represents one of the key prerequisites for improving teaching and learning, this study served a twofold purpose. First, we examined the internal structure and reliability of the teacher academic optimism scale in the Serbian school context. Second, we intended to examine the measurement invariance of the academic optimism scale across teaching levels. Confirmatory factor analysis was applied to the data collected from 420 teachers employed in primary schools in Serbia using the dynamic fit index approach. We found that the three-factor measurement model has satisfactory fit indices according to both traditional and tailored cutoffs. Furthermore, all three levels of measurement invariance were empirically supported. Although all three subscales have good internal consistency, our findings suggest that the conditional reliability of sum scale scores varies. Implications for researchers and practitioners are derived from the obtained findings.