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Date: October 8, 2020
Time: 12:30 p.m. - 2:00 p.m.
Location: Virtual event
Category: Seminar

Aaron Chalfin
Department of Criminology
University of Pennsylvania

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This research reports the first empirical estimate of the effect of police manpower on homicide victimization by race in the United States. Using national microdata on homicides and two different instrumental variables approaches, we find that each additional police officer hired abates between 0.06 and 0.1 homicides. In per capita terms, the effects are 2-3 times greater for Black versus white victims. For both Black and white citizens, it is unlikely that the lives saved by police are fully offset by the taking of lives by police officers during interactions with members of the public.  However, for Black citizens, we cannot rule out that the offsetting effects are important in magnitude. We also find strong evidence that larger police forces make more arrests for low-level "quality-of-life'" offenses, the effects of which are borne disproportionately by Black Americans. On the other hand, there is little evidence that a larger police force leads to an increase in the rate at which homicides are cleared by arrest, providing support for the narrative that Black communities are both over- and under-policed.  The evidence thus suggests that while additional police deter serious violence and, on net, save Black lives, young Black men also bear the costs of additional police presence through the net widening effects of greater enforcement activity.


Shooshan Danagoulian




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