The last 60 years have seen the emergence of a dramatic socioeconomic gradient in marriage, divorce, cohabitation, and childbearing.

We show that the widely used Boston Mechanism (BM) fosters ability and socioeconomic segregation across otherwise identical public schools, even when schools do not have priorities over local students.

This paper examines peer effects in a Chinese middle school where: 1. classes are randomly assigned to teachers, and 2. student quality across classes varies because student assignment is based on a noisy measure of student quality.


The Oxford Series on Human Capital and Economic Opportunity will present state-of-the-art research from a variety of perspectives on the problems of opportunity, human flourishing, and public policy. Volumes in the series will be grouped in accordance with these themes and will be based on the work of HCEO members. In some cases, the volumes will contain research first presented at HCEO conferences, and in others will contain specially commissioned research. The series is published by the Oxford University Press.