Using data from the Chicago Police Department on complaints filed by civilians and reports of force filed by officers, this paper estimates the effect of body-worn cameras (BWCs) of officer and civilian behavior. Using a two-way fixed effects design, I find BWCs are associated with a 29% reduction in use-of-force complaints, driven by white officer-black civilian complaints. Additionally, I find a 34% reduction in officers reporting striking civilians and a large though less significant reduction in officer firearm usage, potential mechanisms for the reduction in complaints. Importantly, I find no change in officer injury or force from civilians. However, I find evidence of de-policing as officers make fewer drug-related arrests following BWC adoption.

中文翻译：

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用随身摄像机监控警察：来自芝加哥的证据

本文利用芝加哥警察局关于平民提出的投诉和警察提出的武力报告的数据，估计了执法记录仪 (BWC) 对警察和平民行为的影响。使用双向固定效应设计，我发现生物武器公约与使用武力投诉减少 29% 相关，这是由白人军官和黑人平民投诉推动的。此外，我发现报告袭击平民的警官数量减少了 34%，警官枪支使用量也大幅减少，但幅度不大，这是减少投诉的潜在机制。重要的是，我发现军官受伤或平民暴力没有变化。然而，我发现了警察去警察化的证据，因为在《生物武器公约》通过后，警察因毒品相关的逮捕数量减少了。