Here today, gone tomorrow? Revisiting the stability of teachers' achievement goals

•Teachers' achievement goals differed in their stability.•Teachers' learning goals were the least stable.•The number of measurement points needed for a reliable measure varied from 1 to 3.

Teachers' achievement goals are typically considered to be stable characteristics although there are arguments for both stability and instability. Empirical investigations regarding the stability of teachers' achievement goals are rare. In this study, we investigated the stability of teachers' achievement goals (i.e., learning, performance approach, performance avoidance, and work avoidance goals) using generalizability theory. The sample comprised 166 German mathematics teachers in academic-track secondary schools who completed self-report questionnaires three times over the course of one school year. The ratio of stable to unstable aspects of teachers' achievement goals varied between 2:1 and 4:1. The number of measurement points needed for a reliable measure of the trait aspects of achievement goals varied between one and three. The results underline the importance of advancing research on teachers' achievement goals both theoretically and methodologically.