What remains of the relative age effect? Selection, achievement, and educational tracking

Relative age effects (RAEs) arise because students within the same grade may differ in age by up to one year. While a large literature documents substantial RAEs in educational achievement, it typically pays less attention to how compliance with school-entry rules and subsequent grade progression shape the RAE that remains observable later in students’ school careers. Using linked administrative and achievement-test data from Switzerland, we examine RAEs at the end of primary school, for students who entered school on time and progressed through primary school without grade repetition. We show that selection, particularly at school entry, substantially alters the observed RAE and generates pronounced heterogeneity across student groups. Among students with regular school trajectories, significant RAEs are concentrated among girls and students from socioeconomically disadvantaged backgrounds. Yet even among girls, for whom the RAE is most pronounced, the achievement advantage of relatively older students is too small to translate into a higher probability of entering the most academically demanding track at the lower-secondary level.