Working Paper: NBER ID: w18815
Authors: Aaron Chalfin; Justin McCrary
Abstract: We argue that the key impediment to accurate measurement of the effect of police on crime is not necessarily simultaneity bias, but bias due to mismeasurement of police. Using a new panel data set on crime in medium to large U.S. cities over 1960- 2010, we obtain measurement error corrected estimates of the police elasticity of the cost-weighted sum of crimes of roughly -0.5. The estimates confirm a controversial finding from the previous literature that police reduce violent crime more so than property crime.
Keywords: police; crime; elasticity; measurement error; public policy
JEL Codes: H76; J18; K42
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Previous estimates of police effectiveness understated true effect (J45) | By a factor of five (C29) |
| Increase in spending on police (H56) | Increase in social value (O35) |
| Increase in police presence (H76) | Decrease in crime rates (K14) |
| Increase in police presence (H76) | Decrease in violent crime (K42) |
| Increase in police presence (H76) | Decrease in property crime (K42) |
| Measurement error correction (C20) | Consistent estimation of police elasticity of crime (C13) |