The Koper Curve

Here is a quick primer on the Koper Curve from the National Policing Institute.

And here is the original publication that discusses the statistics.

Koper, C. S. (1995). Just enough police presence: Reducing crime and disorderly behavior by optimizing patrol time in crime hot spots. Justice Quarterly, 12(4), 649-672.

A full version appears to be available here.