Do Peers Matter in the Police Academy?
利用芝加哥警察学院的抽签系统，研究同伴构成对警员未来逮捕行为的影响，发现更多来自低攻击性群体（如女性和年长警员）的同伴会减少所有警员的低级别逮捕，且同伴种族会放大性别和年龄效应。
Increasing underrepresented groups’ representation in police departments is a common proposal to reduce aggressive policing. This paper documents the effects of peer composition in the Chicago police academy on officers’ future arrests by exploiting the lottery system, which provides exogenous variation in cohort composition. I find that higher shares of peers from groups that police less aggressively, such as female and older officers, reduce all officers’ future low-level arrests. Peer race matters by amplifying the effects of gender and age. Overall, the results are most consistent with peers’ preferences for less aggressive policing shifting officers’ preferences and changing future behavior.