We present a multi-year study of the rollout of Body-Worn Cameras (BWCs) to the New York City Police Department (NYPD). Our study adds to the prior body of work by clarifying some of the discord within it, particularly with respect to large urban police departments. We estimate the effect of BWC deployment on precinct volumes of citizen stops, arrests, complaints against officers, and use-of-force incidents. Results indicate that BWCs drive significant increases in stops and decreases in arrests and citizen complaints. We observe no effect on use of force. We also document heterogeneity in affected stops and complaints. Our findings speak to three potential benefits of BWCs in urban law enforcement: an increase in legitimate stops made by police; a decrease in complaints alleging officers’ abuse of authority; and a reduction in arrests (which appears beneficial, regardless of whether this results from improved behavior among police or citizens).

中文翻译：

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谁在看守望者：随身摄像机对纽约市警务的影响的证据

我们向纽约市警察局 (NYPD) 展示了一项关于推出随身携带相机 (BWC) 的多年研究。我们的研究通过澄清其中的一些不和谐来增加先前的工作，特别是在大型城市警察部门方面。我们估计了 BWC 部署对辖区内公民拦截、逮捕、对警察的投诉和使用武力事件的影响。结果表明，BWC 显着增加了拦截次数，减少了逮捕和公民投诉。我们观察到对使用武力没有影响。我们还记录了受影响站点和投诉的异质性。我们的研究结果说明了 BWC 在城市执法中的三个潜在好处：增加警察的合法拦截；指控官员滥用职权的投诉减少；