The long-term differential achievement effects of school socioeconomic composition in primary education: A propensity score matching approach

Background. The effects of school socio-economic composition on student achievement growth trajectories have been a hot topic of discussion among politicians around the world for many years. However, the bulk of research investigating school socio-economic composition effects has been limited in important ways. Aims. In an attempt to overcome the flaws in earlier research on school socioeconomic composition effects, this study used data from a large sample, followed students throughout primary education, addressed selection bias problems, identified the grade(s) in which school socio-economic composition mattered the most, and studied the differential effects of school socio-economic composition by individual socio-economic status (SES). Sample. In a longitudinal design with seven occasions of data collection, the authors drew on a sample of N = 3,619 students (age at T1 about 5 years, age at T7 about 12 years) from 151 primary schools in Flanders (the northern part of Belgium). Method. Students in low-, medium-, high-, and mixed-SES schools were matched using propensity scores. To compare students' achievement growth trajectories in the different school compositions, multilevel regression modelling with repeated measurements was applied. Results. The results showed that students had more positive achievement growth in high-SES as compared to low-SES and mixed-SES schools. In two of the three comparisons, students in mixed-SES schools showed the lowest math development. The negative effects of mixed-SES schools on math achievement growth were the strongest for high-SES students. Conclusions. Our findings contribute to the ongoing discussion on the effects of school socio-economic composition on student achievement growth.