In their state-of-the-art review on educational effectiveness research (EER), Reynolds et al. (2014) mention that EER addresses two core, foundational questions, namely "What makes a 'good' school? and "How do we make more schools 'good '?" (p. 197). To answer these questions, all the factors within schools and the educational system that might affect learning outcomes of students in both their academic and social-emotional development are foci of EER. The ultimate goal is to understand existing practices, and to establish and test models and theories in order to explain why some schools, learning environments and teachers are more effective than others, and in what way they are more effective (Creemers, 2007).About three decades ago, these questions were picked up by a scholar from the Netherlands, namely Bert Creemers, who summarized around the mid-1980s the literature on educational research and, in particular, school effectiveness research done so far to support the creation of an outline for a new structure of secondary education in the Netherlands as well as to enhance the quality and effectiveness of Dutch education (Creemers, 1983;Creemers & Schaveling, 1985). A few years later, he started to collaborate and write papers with Jaap Scheerens, a Dutch scholar experienced in, among other things, educational evaluation and school organization research. At the end of the 1980s, a scholar from the Flemish-speaking part of Belgium (Flanders), namely Jan Van Damme, got triggered by the same questions too, and