A longitudinal study on the stability over time of school and teacher effects on student outcomes

This paper reviews educational effectiveness theory, concentrating on the time stability of the teacher and school effect. The contribution of longitudinal studies investigating the long-term effect of schools and teachers to modelling educational effectiveness is discussed. Findings of a longitudinal study on the progress of students (N=1681) in mathematics during their first four years at the primary school are presented. Results of this study reveal that traditional approaches of measuring educational effectiveness tend to overestimate the short-term effects of teachers and student background factors and underestimate the long-term effects of teachers and schools. Implications of findings for the theory of educational effectiveness and especially for the concepts of teacher and school effects and their stability are drawn. Finally, suggestions for establishing evaluation mechanisms to improve practice are provided.