When and why do initially high-achieving poor children fall behind?

In this paper, we examine the trajectories of initially higher- and lower-achieving children from lower and higher socio-economic status families from primary school through to university in England for the first time. We also explore what explains these trajectories. This enables us to provide new insights into when and why the performance of children with similar initial achievement diverges on the basis of their socio-economic background. Our results indicate that pupils from poor backgrounds who are higher achievers in primary school fall behind their better-off but lower-achieving peers during secondary school. This suggests that secondary school may be a critical period to intervene to prevent poor children from falling behind their richer peers. Our analysis suggests that there is less divergence in performance between pupils from different socio-economic backgrounds who attend the same schools. This result is particularly strong for children with low initial achievement. While we remain cautious about the implications of these findings, they provide suggestive evidence that schools (or the sorting of pupils into schools) play an important role in explaining why the test scores of richer and poorer children diverge over time.