Heritability, family, school and academic achievement in adolescence

•Genetically informed design was applied to Polish administrative exam data.•Information on adolescent twin zygocity was estimated by a mixture ACE model.•From 58% to 88% of variance in exam results was attributable to heritability.•Up to 34% of variance in exam results was due to common environment.•There were no classroom effects on student progress made between Years 6 and 9.

We demonstrate how genetically informed designs can be applied to administrative exam data to study academic achievement. ACE mixture latent class models have been used with Year 6 and 9 exam data for seven cohorts of Polish students which include 24,285 pairs of twins. Depending on a learning domain and classroom environment history, from 58% to 88% of variance in exam results is attributable to heritability, up to 34% to shared environment and from 8% to 15% depends on unique events in students’ lives. Moreover, between 54% and 66% of variance in students’ learning gains made between Years 6 and 9 is explained by heritability. The unique environment accounts for between 34% and 46% of that variance. However, we find no classroom effects on student progress made between Years 6 and 9. We situate this finding against the view that classroom peer groups and teachers matter for adolescent learning.