Chicago After Shotspotter

In September 2024, Chicago ended its contract with ShotSpotter, which turned off all gunshot-detection sensors across the city. Many warned the move would slow police response times and drive up violent crime. This site uses data obtained via FOIA and the Chicago Data Portal to test these concerns. Priority 1 non-gunshot emergency response times also improved in areas that formerly had ShotSpotter sensors. Scroll down to explore the story. Beats in Chicago that formerly had ShotSpotter sensors saw an average response time improvement of 4.2 minutes after ShotSpotter was removed.

Response Time
Change (min)
+10 min
0
–10 min
This map shows how Priority 1 emergency response times, the fastest-required responses to the most serious incidents, changed across Chicago police beats after ShotSpotter was shut down in September 2024. Blue beats saw faster response times after the shutdown. Red beats saw slower response times. Beats that formerly had ShotSpotter sensors are outlined in black.
Beats that formerly had ShotSpotter sensors (outlined in black) saw an average Priority 1 response time improvement of 4.2 minutes after ShotSpotter was removed, roughly twice the improvement seen in beats without ShotSpotter. This suggests that officers previously tied up responding to ShotSpotter alerts could now prioritize Priority 1 emergency calls.
We also looked at this a different way. Rather than comparing the six months before and after the shutdown, we compared the first nine months of 2024 to the first nine months of 2025. This approach accounts for seasonality, since crime and police activity tend to follow similar seasonal patterns year to year.
The pattern holds. Beats that formerly had ShotSpotter sensors improved by an average of 2.36 minutes, more than twice the 1.10-minute improvement seen in beats that never had ShotSpotter.
Violent Crime
% Change
+60%
0%
–60%
This map of police beats shows the percent difference in violent crime through the first nine months between 2024 and 2025. Darker blue areas represent larger decreases in violent crime. Darker red areas represent violent crime increases.
In September 2024, Chicago cancelled their contract with Shotspotter which installed sensors all over Chicago to detect gunshots. Despite concerns that decommissioning Shotspotter would increase crime and gunshot related deaths, police beats with Shotspotter sensors saw a 11.30% decrease in violent crime and a 32.1% decrease in homicide.
Chicago Police Superintendent Larry Snelling claimed the department’s hotspot analysis has helped reduce violent crime. Police beats with crime hotspots saw a decrease of 11.07% in violent crime and a 33.62% decrease in homicides.
Chicago, Cook County, and the State of Illinois have also increased investments in violence prevention programs, in particular Peacekeepers. This program trains community members as outreach workers to prevent violence. Areas with a Peacekeeper hotspot saw a decrease in violent crime of 12.40% and a decrease in homicides of 63.22%, beating the citywide average.
There are of course other things that may contribute to a decrease in violent crime and police response times. Use the buttons below to explore the map yourself.