This op-ed was written by Co-Director of the Crime Prevention Lab, Eric Piza, for Vital City.
Research shows the technology doesn’t reduce shootings or increase clearance rates, but it may have other benefits.
On February 13, Chicago Mayor Brandon Johnson announced that the city’s ShotSpotter gunshot detection system would be discontinued, with a phasing out of the technology set to begin this September. ShotSpotter is the global leader in gunshot detection technology — a network of acoustic sensors that pinpoints the location of gunfire and typically alerts the police quicker than 911 calls. SoundThinking, ShotSpotter’s vendor, reports that over 250 agencies worldwide (including the NYPD) have adopted their platform. Chicago initially installed ShotSpotter in September 2012 within an approximately three-square-mile area, with coverage expanding to 136 square miles by May 2018. Annual costs advertised on the SoundThinking website ranged from $8.8 to $12.3 million per year for maintaining this coverage.
In the leadup to his decision, Johnson cited concerns that ShotSpotter was unreliable, overly susceptible to human error and played a pivotal role in the police killing of 13-year-old Adam Toledo. Critics say the cancellation was politically motivated and insist ShotSpotter is a vital policing tool. Regardless of political motivations, an honest review of the research evidence suggests the decision to cancel ShotSpotter makes sense.
In 2019, my colleagues and I were awarded a grant from the National Institute of Justice to evaluate the effect of ShotSpotter in Chicago and Kansas City. Incorporating more than 15 years of crime, calls for service and police enforcement data, our study is the largest evaluation of the technology to date. We incorporated a matched quasi-experiment, meaning that the ShotSpotter areas were compared to control areas that shared relevant characteristics but were not covered by ShotSpotter. Such similarity between the ShotSpotter and control areas helped ensure we made “apples-to-apples” comparisons in our analysis.
