Working Paper: NBER ID: w27324
Authors: Tanaya Devi; Roland G. Fryer Jr.
Abstract: This paper provides the first empirical examination of the impact of federal and state "Pattern-or-Practice" investigations on crime and policing. For investigations that were not preceded by "viral" incidents of deadly force, investigations, on average, led to a statistically significant reduction in homicides and total crime. In stark contrast, all investigations that were preceded by "viral" incidents of deadly force have led to a large and statistically significant increase in homicides and total crime. We estimate that these investigations caused almost 900 excess homicides and almost 34,000 excess felonies. The leading hypothesis for why these investigations increase homicides and total crime is an abrupt change in the quantity of policing activity. In Chicago, the number of police-civilian interactions decreased by almost 90% in the month after the investigation was announced. In Riverside CA, interactions decreased 54%. In St. Louis, self-initiated police activities declined by 46%. Other theories we test such as changes in community trust or the aggressiveness of consent decrees associated with investigations -- all contradict the data in important ways.
Keywords: policing; crime; pattern-or-practice investigations
JEL Codes: J0; J15; K10
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Investigations not preceded by viral incidents (Y50) | Reduction in homicides (R28) |
| Investigations not preceded by viral incidents (Y50) | Reduction in total crime (K42) |
| Investigations preceded by viral incidents (Y50) | Increase in homicides (K42) |
| Investigations preceded by viral incidents (Y50) | Increase in total crime (K42) |
| Investigations preceded by viral incidents (Y50) | Decline in policing activity (K42) |
| Decline in policing activity (K42) | Increase in crime (K42) |
| Investigations not preceded by viral incidents (Y50) | Little to no impact on crime rates (K14) |
| Investigations preceded by viral incidents (Y50) | Sharp decline in police-civilian interactions (K42) |