British secondary schools moved from a system of extensive and early selection and tracking in secondary schools to one with comprehensive schools during the 1960s and 70s. Before the reform, students would take an exam at age eleven, which determined whether they would attend an academically...

We estimate peer effects for fourth graders in six European countries. The identification relies on variation across classes within schools. We argue that classes within primary schools are formed roughly randomly with respect to family background. Similar to previous studies, we find sizeable...