Do Some Schools Mitigate and Others Exacerbate Inequality? Between-School Variation in the Income-Achievement Association

Whether schools mitigate or exacerbate social inequality has been debated for decades. Much of the evidence concerns the average effect of schooling relative to its absence, while less is known about whether schools differ in how strongly parental income predicts achievement. Using population-wide register data on 759,037 students in 2,699 Norwegian primary schools, we show that the income-achievement association in 8th grade varies considerably across schools. In some schools, the association is more than twice as large as in others, and the variation persists when we adjust for family background and 5th-grade test scores. It is largely unrelated to the socioeconomic composition of schools, but the association is somewhat weaker in schools with higher value-added, which contribute more to students’ learning. If this variation reflects what schools do, schooling can be compensatory on average while some schools do much less than others to weaken this association. Schools then differ in how much parental income matters for their students’ achievement, not only in how much their students learn.