Booij, Adam S.; Leuven, Edwin; Oosterbeek, Hessel - 2015
students in economics. We manipulated the composition of groups to achieve a wide range of support, and assigned students … students of low and medium ability gain on average 0.2 SD units of achievement from switching from ability mixing to three …-way tracking. Their dropout rate is reduced by 15 percentage points (relative to a mean of 0.6). High-ability students are …