In this contribution we report about a project about Professional Learning Communities.This project combines development and research. In this contribution we pay attention to the effect of the organisational capacity of a school on the personal and interpersonal capacity and to the impact of a professional
learning community on the self and collective efficacy of teachers and on the innovative attitude in the school. In order to answer these questions, we obtained data from a survey of 67 schools in the
Netherlands. On the base of the results we can conclude that a school as a professional learning community influences in a positive way the collective efficacy and the innovative attitude. These attitude and feelings of efficacy can be regarded as a sustainable source for teaching and school improvement.