Chicago is the latest city rethinking disputed technology that listens for gunshots

Chicago has joined a growing list of cities that have cut ties with a controversial company that tries to reduce urban gun violence with 24/7 technology that listens for the crack of gunshots and immediately notifies police.

This month, Chicago Democratic Mayor Brandon Johnson announced the city would not renew its contract with SoundThinking, the California-based company behind ShotSpotter, software that uses a network of hidden neighborhood sensors to detect the sound of gunfire.

Chicago was spending around $9 million annually on one of the biggest installations in the country, covering around 100 square miles.

More than 150 cities nationwide use ShotSpotter in an effort to help police departments respond to more incidences of gunfire, which often go unreported by residents. Cities that have recently shown new or continued interest in the technology include Cleveland, Seattle and Little Rock, Arkansas.

Leaders say it can help save gunshot victims’ lives by enabling emergency responders to get to the scene of a shooting more quickly. As a result, they add, investigators can more quickly recover ballistic and bullet casing evidence used to solve crimes.

But over the past decade, cities around the country such as Atlanta; Charlotte, North Carolina; New Orleans; and San Antonio, Texas, have decided to discontinue their use of ShotSpotter. Those decisions coincided with a growing body of research showing that ShotSpotter has not succeeded in reducing gun violence, has slowed police response times to emergency calls, and often did not lead to evidence recovery. SoundThinking has vigorously disputed criticism about ShotSpotter’s efficacy.

As cities continue to reevaluate their strategies for bringing down gun assault numbers, which spiked during the pandemic and are slowly falling, they must focus on tools that are proven to keep their communities safe, especially with strained resources, said Thomas Abt, a senior fellow at the Council on Criminal Justice, a nonpartisan think tank, and an associate research professor in criminology and criminal justice at the University of Maryland.

“It’s troubling to have a powerful for-profit vendor pushing this strategy that has been widely adopted, but there’s not a lot of evidence that it’s particularly effective,” Abt said.

The Chicago mayor’s office reiterated that concern when it announced Johnson’s decision to stop using ShotSpotter, saying the city “will deploy its resources on the most effective strategies and tactics proven to accelerate the current downward trend in violent crime.” The city plans to decommission the software on Sept. 22.

Johnson’s decision makes good on a campaign promise he made during last year’s mayoral election, when he called the technology “unreliable.” An earlier investigation by Chicago’s inspector general found that ShotSpotter alerts “rarely produce documented evidence of a gun-related crime, investigatory stop, or recovery of a firearm.”

“The technology was not making residents safer and wasn’t a useful community safety tool. I think it will raise questions for other cities,” said Jonathan Manes, a Chicago-based attorney with the MacArthur Justice Center. The center released a report in 2021 that found the city’s use of ShotSpotter led to investigatory dead-ends and more police monitoring in communities of color.

SoundThinking did not agree to an interview with Stateline. In a statement, however, the company said that until September, it “will continue to provide the Chicago Police Department and the citizens of Chicago with the highest-quality gunshot detection services that the city has relied upon for the last seven years.”

City aldermen have been split on Johnson’s decision, with some agreeing the software did not use taxpayer dollars wisely on an academically disproven and expensive technology, and others saying it will make communities plagued by gun violence less safe and harder for police to do their jobs.

Around the country, ShotSpotter remains a popular tool in police departments, as more cities consider adopting or expanding their use, even as criticism slowly gains traction.

How police listen for gunfire

In California, the suburban city of Richmond, just across the bay from San Francisco, has been using ShotSpotter for the past decade. When the microphones installed around the city of 114,000 detect gunfire, alerts are sent both to emergency dispatchers and to officers through an app on their phones.

The alert shows how many rounds of gunfire were detected, what sort of firearm was used and a pinpoint dot that gives a search radius for where the shots were fired. ShotSpotter uses 20 sensors per square mile.

Through the app, officers also can listen to an audio file of the shots. Using this information, dispatchers send officers to the scene to see whether there are victims and to collect evidence.

The details give officers a defined area in which to search instead of using “the old school way” of responding to a 911 call from a resident who heard but didn’t see gunfire, unable to say exactly where the shots were fired, said Lt. Donald Patchin of the Richmond Police Department.

He pointed to a December incident in which ShotSpotter was instrumental in leading to the arrest of two people and the confiscation of two firearms, using the location of the gunshot detection as a launching point to gathering evidence. The information isn’t used as the sole piece of evidence in prosecuting crimes, but it can help law enforcement, Patchin said.

“Unequivocally, it has resulted in us getting firearms out of the hands of felons and people that aren’t allowed to have guns, and we’ve got them off the street,” he said. “We’re fairly happy with the system.”

Last year, Richmond saw a record low number of homicides since the city started tracking data in 1971, which Patchin in part attributes to ShotSpotter.

In Seattle, the police department will test ShotSpotter this year, subject to public comment. The city council heeded calls from Democratic Mayor Bruce Harrell to inject $1.5 million into the budget for the pilot program after Seattle set a homicide record last year.

Seattle badly needs the technology alongside community-led public safety plans, said the Rev. Harriett Walden, co-founder of Mothers for Police Accountability, a local grassroots group. Too many children, especially in Black communities, are being traumatized by gunfire, she said.

“We have to see if this works for us,” Walden said, “if ShotSpotter can help us be able to get some arrests, be able to get people to the scene right away, and then be able to talk to young people about trauma and how this is not normal behavior.”

Growing criticism

Even as cities continue to use ShotSpotter, though, many others are reconsidering their contracts.

Over the past year, leaders in Dayton, Ohio; Durham, North Carolina; and Portland, Oregon, have decided not to use ShotSpotter. Portland, for instance, found the software was not likely to reduce enough gun violence for the amount of money the city would need to spend. Leaders said they would concentrate on proven community outreach programs that targeted people most likely to commit gun violence at the micro level, instead of listening devices.

“It’s all bunk, but it’s a good sell for cities that are hard-strapped for a way to stop gun crime,” said Eleni Manis, research director for Surveillance Technology Oversight Project, a New York City-based nonprofit that fights police surveillance of American communities. “It’s a technological boondoggle.”

Manis and her colleagues published a 2022 report showing that ShotSpotter had a difficult time weeding out noises that sounded like gunfire, such as fireworks or cars backfiring. The report also documented research showing that the program’s use doesn’t reduce gun crimes. And it doesn’t improve the medical outcomes of gunshot victims, police officers’ ability to clear homicide cases or communities’ cooperation with police.

“My primary beef goes beyond whether it works or not,” Manis said. “It doesn’t actually promote public safety. It really wastes officers’ time.”

A November working paper out of the University of California, Santa Barbara found that in Chicago, police officers spent so much time responding to ShotSpotter detections, some of which were false, that it took them significantly longer to respond to real emergencies. Also, because police arrived later to the scenes of actual shootings, they were less likely to make arrests.

For a police department such as Chicago’s, which is suffering from officer and funding shortages, ShotSpotter exacerbates institutional challenges by reallocating resources away from other 911 calls, said Michael Topper, a doctoral candidate in economics and co-author of the study.

“If you implement this technology that requires officers to do more work, then their other work is also going to suffer,” Topper said. “Police departments must evaluate what they have before starting to implement it.”

SoundThinking, the company behind ShotSpotter, vehemently disagrees with these studies, saying on its website that the gunshot detection technology has a high accuracy rate, while also helping police and emergency responders get to shooting scenes more quickly.

What is clear is that police who use the technology do find out about more gunshots than they did before using it, said Justin Nix, an associate professor of criminology and criminal justice at the University of Nebraska Omaha.

He wrote a study on Omaha’s use of ShotSpotter that found the police department would not have known about thousands of gunshots from 2014 to 2017 if not for the software. But while ShotSpotter led to more police reports, it did not produce more arrests than 911 calls did. If cities are going to use this tool, he said, they have to understand its limitations.

“Maybe it has a great deal of potential that hasn’t been realized yet,” Nix said. “But there’s no concrete evidence to date that would lead us to be confident that this is where we should put our dollars.”

Stateline is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. Stateline maintains editorial independence. Contact Editor Scott S. Greenberger for questions: [email protected]. Follow Stateline on Facebook and Twitter.