This article describes the process of theoretical reflection that preceded the development and empirical verification of a model of “effective school improvement”. The focus is on basic mechanisms that could be seen as underlying “getting things in motion” and change in education systems. Four mechanisms are distinguished: synoptic rational planning, the market mechanism, cybernetics, and autopoiesis. Principles relevant for effective school improvement that are deducted from these basic mechanisms are: goal setting for improvement, pressures to improve, cyclical improvement processes, and autonomy. The article also briefly touches upon the way empirical models of school effectiveness and school improvement can be linked and used in the encompassing model of effective school improvement that the ESI project has yielded.