It is well known that there were significant spikes in homicides in 2020, particularly in major urban areas. In an article I published in 2021, I attributed these spikes to what I dubbed the “Minneapolis Effect”–specifically reductions in proactive policing as police pulled back in the wake of the George Floyd protests. {snip}

A few days ago, an important new statistical study found corroboration for my hypothesis in New York City. Professor Dae-Young Kim’s article “Did De-Policing Contribute to the 2020 Homicide Spikes?” answers the question posed in the title in the affirmative.

Professor Kim’s article examines NYC homicide data from 2017 through 2020. It divides homicides into six different categories: gun, non-gun, domestic, non-domestic, gang, and non-gang. It assesses the connection between homicide rates in those categories and a significant reduction  in NYPD police stops of pedestrians. In NYC, stops fell from 13,453 in 2019 to 8,375 in 2020–a 30% decrease in proactive policing.

Professor Kim’s article found that the reduction in stops led to an increase in three homicide categories:

… the interaction term of police stops and the pandemic presents the extent to which the 2020 homicide surges were attributable to reduced proactive law enforcement. Specifically, gun, non-domestic, and gang homicides significantly increased as police stops decreased in the pandemic and post-Floyd era. In addition, the supplementary correlation analyses present a significant correlation of police stops to gun (r=−.406, p =.008), non-domestic (r=-.321, p=.041), and gang (r=−.364, p=.019) homicides, respectively, in the pandemic and post-Floyd era. In contrast, the significant correlations disappear in the pre-intervention era.

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The explanation Professor Kim gives for this pattern tracks the one that I gave in my paper on the “Minneapolis Effect”–specifically, that police stops are targetted at gun crimes and related gang activity, and thus a reduction in stops will produce the greatest increase in homicides in these specific categories. As Professor Kim puts it:

Pedestrian stops are used to stop and frisk anyone, but mostly known gang members, on the street they suspect might engage in criminal activity or carry concealed weapons. Given the goal of pedestrian stops, the effects of de-policing should be more pronounced on gun, non-domestic, and gang homicides that usually occur in public settings. {snip}

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