This paper presents the methods and the main results of the 6 studies which were conducted in order to test the validity of the comprehensive model of educational effectiveness. The synthesis of these studies reveals that some support to the model has been provided. It is also demonstrated that 2 characteristics of the comprehensive model concerned with its multilevel nature can be seen as starting points for the development of the dynamic model of effectiveness, which is able to establish strong links between effectiveness research and improvement of practice. Finally, the results of these studies reveal the importance of 4 elements of the dynamic model concerned with its attempt to (a) use a framework to measure the functioning of effectiveness factors, (b) take into account new theories of learning in defining classroom-level factors, (c) incorporate results of differential effectiveness research, and (d) illustrate the dynamic perspective of effectiveness. (Contains 1 table.)