Several studies have shown that socioeconomic composition has an effect on student achievement (Dumay & Dupriez, 2008; Opdenakker & Van Damme, 2001; Rumberger & Palardy, 2005; Sykes & Kuyper, 2013). Socioeconomically disadvantaged students face a double handicap because they are in classes with other socioeconomically disadvantaged students. As a higher level of segregation indicates important differences between classes, I made the hypothesis that the effect of composition is similar across segregated countries. The modeling of composition requires a full set of individual variables, including a measure of prior achievement (Raudenbush & Willms, 1995; Thrupp, Lauder, & Robinson, 2002). Such measures are only partially available in PIRLS. Consequently, I have to explicitly assume that delay and other variables measuring pupil background can account for prior achievement and limit the omission bias in the measure of the composition effect. Countries included in the model were cautiously selected on the basis of their level of segregation and the accumulation of delay. This paper aims to model the potential differential effect of school composition on pupils’ achievement in Belgium, France, Spain, and Portugal. Multilevel models are tested on the PIRLS 2011 data (20830 pupils in 1139 classes). The compositional effect was measured by averaging socioeconomic background of all students in a class. Countries were entered as a class-level dummy, and interactions between countries and composition enable us to test if a variable has a different effect in the four countries. Our results suggest that socioeconomic composition does not have an equivalent effect on pupil achievement in the four countries. Its effect is strong in Belgium and France but smaller in Spain and Portugal. While the composition effect is a useful concept to describe the detrimental effect of segregation on disadvantaged pupils, it seems that socioeconomic segregation is not sufficient to observe large socioeconomic compositional effects.

Condron, D. J. (2009). Social class, school and non-school environments, and black/white inequalities in children’s learning. American Sociological Review, 74(5), 685–708. Dumay, X., & Dupriez, V. (2008). Does the school composition effect matter? Evidence from Belgian data. British Journal of Educational Studies, 56(4), 440‑477. Opdenakker, M.-C., & Van Damme, J. (2001). Relationship between school composition and characteristics of school process and their effect on mathematics achievement. British Educational Research Journal, 27(4), 406‑428. Raudenbush, S. W., & Willms, J. D. (1995). The Estimation of School Effects. Journal of Educational and Behavioral Statistics, 20(4), 307‑335. Rumberger, R. W., & Palardy, G. J. (2005). Does the segregation still matter ? The impact of student composition on academic achievement in high school. Teachers College Record, 107(9), 1999‑2045. Sykes, B., & Kuyper, H. (2013). School Segregation and the Secondary-School Achievements of Youth in the Netherlands. Journal of Ethnic and Migration Studies, 39(10), 1699–1716. Thrupp, M., Lauder, H., & Robinson, T. (2002). School composition and peer effects. International Journal of Educational Research, 37(5), 483‑504.