Date of Award

June 2020

Degree Type


Degree Name

Doctor of Philosophy (PhD)




Amy E. Schwartz


Education, Heterogeneity, Homophily, Network, Obesity, Peer effect

Subject Categories

Social and Behavioral Sciences


This dissertation consists of three essays on peer effects in elementary school classrooms using data from New York City (NYC) public schools. Each chapter explores a different component of within-classroom interactions in order to build towards an understanding of what makes a peer relevant.

The first chapter proxies for the social network using a set of shared characteristics (homophily). In this coauthored work, we are not interested in measuring the classroom peer effect, but rather we estimate and then rank each network's effect on academic spillovers. This answers the question: which characteristics are socially important, and by how much?

The second chapter uses a novel method to measure the social importance of classmates based on student proximity in the lunch line over the course of the school year. The result is a revealed friendship network which I use to estimate peer effects. To my knowledge, this is the first paper to measure the social importance of classmates and use this to estimate classroom peer effects.

In the third chapter, I use reduced form models to test for the existence of obesity spillovers in elementary school classrooms. I find evidence of significant causal social effects in both BMI and exposure to overweight and obese students.


Open Access