in RIA Executive Summaries

Analyzing Crime Displacement and Diffusion POP
Problem-Oriented Guides for Police (POP’s) summarize knowledge about how police can reduce the harm caused by specific crime and disorder problems by preventing problems and improving overall incident response. This edition explores displacement and diffusion
Crime displacement is the relocation of crime from one place, time, target, offense, or tactic to another as a result of some crime prevention initiative. There are a multitude of types:
• Temporal—offenders change the time at which they commit crime
• Spatial—offenders switch from targets in one location to targets in another location
• Target—offenders change from one type of target to another
• Tactical—offenders alter the methods used to carry out crime
• Offense—offenders switch from one form of crime to another.
Diffusion effects occur when a preventative measure affects surrounding items positively. This benefit is referred to in a variety of ways including the “bonus effect,” the “halo effect,” the “free-rider effect,” and the “multiplier effect.”