It’s fairly common knowledge that large earthquakes are frequently followed by aftershocks, smaller earthquakes that occur in the same locale or relatively nearby. It is less well-known that some types of crime also have a similar aftershock phenomenon. For instance, burglaries are frequently followed by burglaries in the same neighborhood or a neighborhood nearby. This story in The Economist describes how mathematicians like George Mohler at the University of Santa Clara are using this phenomenon to devise methods of predicting where these “aftercrimes” are most likely to occur. The technique literally adapts the same equations used to describe earthquake aftershocks, and appears to hold some promise.
In one test the program accurately identified a high-risk portion of the city in which, had it been adequately patrolled, police could have prevented a quarter of the burglaries that took place in the whole area that day.
Together with researchers at UCLA, Mohler is extending the work to explore another type of crime in which there are often aftershocks: gang violence. Some of that work, and some additional projects involving ‘predictive policing’, are also detailed in the recent LA Times story “Stopping Crime Before It Starts”, by Joel Rubin.