Safety in Police Numbers : Evidence of Police Effectiveness from Federal COPS Grant Applications

Understanding the impact of police on crime is critical to designing policies that maximize safety. In this paper, I use a novel estimation approach to measure the impact of police hiring, which exploits variation in federal Community Oriented Policing Services (COPS) hiring grants, while also controlling for the endogenous decisions of police departments to apply for these grants. Using data from nearly 7,000 U.S. municipalities, I find that a 10% increase in police employment rates reduces violent crime rates by 13% and property crime rates by 7%. The results also provide suggestive evidence that law enforcement leaders are forward-looking