Smartphone Data Reveal Neighborhood-Level Racial Disparities in Police Presence
利用美国21个大城市近万名警察的匿名智能手机数据，研究发现黑人居民比例每增加一个百分点，警察在社区驻留时间增加0.36%，这种差异在控制人口密度、社会经济地位和犯罪需求后依然存在，且与黑人警察主管比例相关。
Abstract Research on policing has focused on documented actions such as stops and arrests—less is known about patrols and presence. We map the neighborhood movement of nearly 10,000 officers across 21 of America’s largest cities using anonymized smartphone data. Police spend 0.36% more time in neighborhoods for each percentage point increase in Black residents. This neighborhood-level disparity persists after controlling for density, socioeconomic status, and crime-driven demand for policing, and may be lower in cities with more Black police supervisors (but not officers). Patterns of police presence statistically explain 57% of the higher arrest rate in more Black neighborhoods.