Hiring more cops doesn't do much. They need to be used more effectively (targeted against a specific problem), rather than thrown at all crime across a city. link.springer.com/article/10.1...
link.springer.com
Conclusions from the history of research into the effects of police force size on crime—1968 through 2013: a historical systematic review - Journal of Experimental Criminology
Objectives We describe and explain how the findings from nonexperimental studies of the relationship between police force size and crime have changed over time. Methods We conduct a systematic review ...