The Lab @ DC, Office of the City Administrator, Executive Office of the Mayor, Washington, DC 20004;
The Policy Lab, Brown University, Providence, RI 02912.
Proc Natl Acad Sci U S A. 2019 May 21;116(21):10329-10332. doi: 10.1073/pnas.1814773116. Epub 2019 May 7.
Police body-worn cameras (BWCs) have been widely promoted as a technological mechanism to improve policing and the perceived legitimacy of police and legal institutions, yet evidence of their effectiveness is limited. To estimate the effects of BWCs, we conducted a randomized controlled trial involving 2,224 Metropolitan Police Department officers in Washington, DC. Here we show that BWCs have very small and statistically insignificant effects on police use of force and civilian complaints, as well as other policing activities and judicial outcomes. These results suggest we should recalibrate our expectations of BWCs' ability to induce large-scale behavioral changes in policing, particularly in contexts similar to Washington, DC.
警察随身摄像机（BWCs）被广泛推广为一种改进警务和警察及法律机构合法性的技术机制，但它们有效性的证据有限。为了评估 BWCs 的效果，我们在华盛顿特区进行了一项涉及 2224 名大都会警察局官员的随机对照试验。在这里，我们表明 BWCs 对警察使用武力和公民投诉的影响非常小，而且统计上不显著，对其他警务活动和司法结果也是如此。这些结果表明，我们应该重新调整对 BWCs 能够在警务中引起大规模行为变化的能力的期望，特别是在与华盛顿特区类似的情况下。
