One of the benefits of the move to data-driven policing is the opportunity to understand how a few risky places disproportionately contribute to the crime problem. Research conducted here in Philadelphia has already identified that violence appears to strongly cluster within 85 feet of bars and extend for up to a block, robberies concentrate around subway stations, and drug arrests can cluster around pawnshops and check-cashing stores. In the last month or two new research by Elizabeth Groff and Brian Lockwood and based on Philadelphia Police data finds that even when controlling for the population characteristics of the immediate area, violent crime is nearly 10% higher on blocks with bars, and disorder is more prevalent up to three blocks from subway stations and schools.
We also know that roughly 20% of places are responsible for causing 80% of the problems for police. Crime scientists call this the Iron Law of Troublesome Places. The iron law holds for banks, convenience stores, gas stations, schools and a whole host of other places. It also holds for bars and subway stations, so it is likely that only a few bars in the city are responsible for the vast majority of major crime around all Philadelphia bars. Now that every district has an analysis coordinator to help with identifying these key locations, the next step is to engage L & I to close the worst places down, or to find other ways to “encourage” owners of the most problematic bars to be more responsive to the crime problem in and around their facilities. In this way the police department can make best use of available resources and engage other city agencies and business owners in the fight against crime.
(A version of this post was first printed in the Philadelphia Police Department ‘Call of Duty’ newsletter under the Intel Driven column).