mathematics and reading test scores, more so for non-LEP students than for LEP students. The overall language mix of LEP students … has little if any discernable relationship with achievement. For LEP students, having more LEP peers speak their mother …

estimates, while causal, may also reflect peer effects due to differences in peer quality of non-randomized students. We exploit … universal random assignment of students to high schools in certain areas of South Korea to provide estimates of school effects …

ideal for investigating this question. There, students are placed in exam schools based on a high-stakes national … large achievement gains and improved university placements for high achieving students. …