Amplified Educational Inequality. School Exposure and Learning by Student Background

Understanding who benefits most from schooling is essential both for sociological stratification theories and for informing educational policy debates about the trade-off between equity and efficiency. Using an elaborate differential exposure model, we provide more precise and nuanced insights into this by studying (1) how school exposure affects gains in reading comprehension and mathematics, and (2) whether it adapts inequalities by parental education, migration background, and gender. Leveraging unique administrative data from the Netherlands Cohort Study on Education on ~600k pupils over multiple grades (Grades 1-5), we exploit the quasi-random variation in test dates and calculate the exposure to schooling by the interval length between the mid-term and end-of-term tests. We find that while school exposure substantially boosts achievement by 0.5 S.D. in reading and 1.1 S.D. in mathematics per school year, these gains are not equally distributed. For reading, children with higher-educated parents and those without non-Western migration backgrounds benefit more from schooling, amplifying inequality. For mathematics, we find small compensatory patterns. These findings show that the effects of schooling on inequality are domain-specific, which we explain by the multiplicative nature of skill acquisition in schools and homes – an interaction that particularly boosts reading development in resourceful families.