In these uncertain times, politicians and society have been voicing
high expectations from teacher education asking for evidence of
added value and impact on the student. In this study a longitudinal
mixed-methods approach was used to determine the
impact of in-service Master of Education programmes on teachers
(N = 1,917) and their work environment in the Netherlands. The
results of online surveys were explained by means of realist evaluation
using focus-group and in-depth interviews. The study
shows that Master of Education programmes had an impact on
professional and pedagogical skills of teachers, and in some cases
also on their work environment. A two-tier mechanism is proposed:
the Master’s programmes provide teachers with more indepth
knowledge about teaching and learning and a more critical
stance through inquiry and research. Consequently, some teachers
contribute to a culture of inquiry in their schools, provided that
the schools facilitate them in new roles.