It is notoriously difficult to identify peer effects within the family, because of the common shocks and reflection problems. We make use of a novel identification strategy and unique data in order to gain some purchase on this problem. We employ data from the universe of children born in...

Schools often track students to classes based on ability. Proponents of tracking argue it is a low-cost tool to improve learning since instruction is more effective when students are more homogeneous, while opponents argue it exacerbates initial differences in opportunities without strong...