The genetic lottery goes to school: Better schools compensate for the effects of students’ genetic differences

TL;DR

This study finds that better schools can reduce educational inequalities caused by genetic differences in students, especially in reading skills.

Contribution

The paper provides causal evidence that school quality can compensate for genetic predispositions to educational attainment.

Findings

A 1 SD increase in school quality reduces the impact of genetic differences on reading scores by 6%.

Compensation occurs mainly for students with lower genetic predispositions to educational success.

No such compensation is observed for numeracy skills.

Abstract

Education is a core determinant of life outcomes, and equity in educational systems is a central policy goal. An important question in the literature is whether schools can reduce inequities arising from social background and genetic differences between children. Using causal estimates of gene–environment interactions in the school context, we investigate whether schools can compensate for genetic differences captured by polygenic indices for educational attainment. We find a negative gene–environment interaction for reading skills but not numeracy, indicating that schools can compensate for the effects of differences in polygenic indices for educational attainment.

In this paper, we investigate whether better schools can compensate for the effects of children’s genetic differences. To this end, we combine data from the Norwegian Mother, Father, and Child Cohort Study (MoBa) with Norwegian register data to estimate the interaction between measures of children’s predisposition to education and school quality. We use MoBa’s genetic data to compute polygenic indices for educational attainment (PGIEA). Importantly, MoBa includes genetic data on mother-father-child trios, allowing us to identify causal genetic effects using within-family variation. We calculate school value-added measures from Norwegian register data, allowing us to causally estimate school quality effects. Leveraging the advantages of both data sources, we provide a causally identified study of gene–environment interactions in the school context. We find evidence for substitutability of PGIEA and school quality in reading but not numeracy: A 1 SD increase of school quality decreases the impact of a 1 SD increase of PGIEA on reading test scores by 6%. The substitutability arises through gains of students at the lower end of the PGIEA distribution. This suggests that investments in school quality may help reduce educational inequalities arising from genetic differences between students.

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