Schools equalizing or exacerbating inequality? Between-school variability in the relationship between socioeconomic background and academic achievement

Whether schools perpetuate or mitigate social inequality has been debated for decades. However, one crucial aspect that has remained unexplored is whether and to what extent inequalities manifest differently across schools. Using administrative data from Norway, our study uncovers that the link between parental income and academic achievement in 8th grade varies considerably across schools. In some schools, achievement gaps are more than twice as large as in others. This highlights that schools do not function as uniform entities; rather, some may exacerbate inequalities while others may play a more compensatory role. In fact, in some successful schools, family-level risk factors remain largely unmanifested. While the achievement gap variability is largely unrelated to the socioeconomic composition of schools, lower-quality schools tend to have a stronger income-achievement association than those of higher quality. Overall, our findings emphasize the necessity of a nuanced understanding of how inequalities manifest across diverse school contexts to fully grasp the role of schooling in social inequality and to devise effective strategies for reducing disparities.