The belief that both the behavior and outcomes of students are affected by their peers is important in shaping education policy. I analyze two polar education systems -tracking and mixing- and propose several criteria for their comparison. I find that tracking is the system that maximizes...

Grade retention practices are at the forefront of the educational debate. In this article, we measure the effect of grade retention on Spanish students' achievement by using data from Programme for International Student Assessment (PISA). We find that grade retention has a negative impact on...

Parents and policy-makers often wonder whether and how the choice of a tracked or mixed educational system affects the equality of opportunity. I answer this question by analyzing the influence of peers on future educational results. I define an equal opportunity policy as one that maximizes the...