Educational leadership and pupil achievement: The choice of a valid conceptual model to test effectsin school effectiveness research

School effectiveness research often uses multilevel models in which only direct effects of characteristics of schools on pupil achievement are modelled. Recently, more attention is given to conceptual models that assume indirect and antecedent effects. In this paper, we elaborate on these models and show that the findings from school effectiveness research are influenced by the conceptual model underlying the analyses. We do this by focusing on the effect of “integrated leadership” on 2 outcome measures: mathematics achievement and mother tongue achievement. Four different conceptual models will be tested by means of multilevel structural equation modelling. Therefore we use data from a school effectiveness research in Flanders (850 fourth graders and 847 sixth graders within 47 schools). The results of these analyses show that the conclusion whether integrated leadership has an effect or not on pupil achievement, is dependent on the choice of the conceptual model.