| It is surprisingly difficult to isolate causal effects of police on crime empirically due to the simultaneous determination of crime and police presence. Instruments are used to address the simultaneity concerns in the previous crime literature. The 2SLS results provide evidence indicating that additional police reduce crime. However, we might suspect whether the same instruments can generate consistent results with previous studies by using datasets of more recent years instead of thirty years ago and considering the change of policies, crime situation, and other factors. This paper use electoral cycles as instrumental variable and updated data of the 1985-2010 period trying to explore the correlation between police and crime using electoral cycles as instruments in different situation. Results show that there are positive elasticities of violent crimes with respect to police as well as negative elasticities for property crimes. Overall, we cannot conclude with strong evidence that increased police reduce crime using electoral cycles as instruments. |
