The Good, the Bad, and the Average: Evidence on Ability Peer Effects in Schools
利用英格兰中学四届学生的全国考试数据，研究发现能力分布底端的差生对同伴成绩有显著负面影响，而平均水平和优秀同伴的影响不大，但女生受益于优秀同伴而男生不受影响。
We study ability peer effects in English secondary schools using data on four cohorts of students taking age-14 national tests and measuring peers' ability by prior achievements at age 11. Our identification is based on within-pupil regressions exploiting variation in achievements across three compulsory subjects tested at age 14 and age 11. Using this novel strategy, we find significant and sizable negative effects arising from bad peers at the bottom of the ability distribution but little evidence that average peer quality and good peers matter. However, these results are heterogeneous, with girls benefiting from academically bright peers and boys not.