Academic self-concept (ASC) is characterized by the dual nature of stability and change. That is, students strive for consistency in their self-concept but also receive achievement feedback that leads to changes in ASC. Only a few previous studies have scrutinized the stability of ASC. The STARTS model (Stable, AutoRegressive Trait, and State) disentangles three sources of variation that underlie individual differences in a construct across time: (a) a time-invariant stable component, (b) a time-varying, partly stable component, and (c) an occasion-specific state component. This study is the first to analyze the stability of ASC with the STARTS model. Rather than selecting a single data set, we followed the idea of using an integrative data analysis (IDA) and applied the STARTS model to 11 longitudinal studies that included more than 20,000 students. Our results show that there is a substantial proportion of stable trait variance in both mathematical (26%) and verbal self-concept (24%)-that is, some sources of individual differences in ASC are completely stable (e.g., genes, preschool environment). The largest part of the variation in ASC across time could be attributed to factors that systematically changed in an autoregressive way (e.g., achievement feedback). Mathematical self-concept showed higher stability than verbal self-concept as a result of a smaller proportion of occasion-specific state variance. The IDA also revealed substantial heterogeneity across studies. We argue that disentangling stable and temporally changing aspects of ASC is important not only for informing theory but also for assessing the potential of psychological interventions.
Educational Impact and Implications StatementPromoting the academic self-concept of students, that is, their confidence in their own academic abilities, is an important educational goal (a) in and of itself and (b) because students with higher self-concepts have been shown to have more successful school careers. In this study, we focused on the stability of academic self-concept-that is, the extent to which it is a student characteristic that is stable or malleable and changing over time. Our study is the first to employ the STARTS model to academic self-concept research showing that there is a completely academic stable self-concept component, but most of the variation over time is only partly stable. Our results further suggest that because academic self-concept changes over students' school careers, it is thus malleable and can be targeted by specific interventions and influenced by teaching practices. Finally, self-concept in mathematics was found to be more stable than self-concept in the language of instruction. One interpretation may be that students hold more fixed beliefs or mindsets about mathematical ability; such beliefs could be challenged by teachers. Overall, our results contribute to the understanding of academic self-concept, which is one of the most important motivational factors in students' school careers.