ABSTRACT
Researchers looking for displacement have sometimes found precisely its reverse. Rather than finding that crime has been pushed to some other place or time, they have found that crime has been reduced more widely than expected, beyond the intended focus of the measures. This is a relatively recent discovery, but already many examples exist:
As expected, electronic tagging of books in a University of Wisconsin library resulted in reduced book thefts. However, thefts also declined of video-cassettes and other materials that had not been tagged.
When a New Jersey discount electronic retailer introduced a regime of daily counting of valuable merchandise in the warehouse, thefts of these items plummeted - but thefts also plummeted of items not repeatedly counted.
When 'red light' cameras were installed at certain junctions in Strathclyde, not only did fewer people 'run the lights' at these locations, but also at other traffic lights nearby.
The implementation of added security for houses that had been repeatedly burgled on the Kirkholt housing estate reduced burglaries for the whole of Kirkholt, not just for those houses given additional protection.
When street lighting was improved in a large housing estate in England, crime declined in both that estate and a nearby one where the lights were not changed.
When vehicle tracking systems were introduced in six large American cities, rates of theft declined citywide, not just for car owners who purchased the devices.
These are all examples of the 'diffusion of benefits' of crime prevention measures. It appears that potential offenders may be aware that new prevention measures have been introduced, but they are often unsure of their precise scope. They may believe the measures have been implemented more widely than they really have, and that the effort needed to commit crime, or the risks incurred, have been increased for a wider range of places, times or targets than in fact is the case.