Critics of ShotSpotter gunfire detection system say it’s ineffective, biased and costly

ShotSpotter – a system intended to detect gunfire and cut police response times – has run into sharp criticism from officials and community groups, with some major cities opting not to deploy the technology.

The acoustic gunshot detection system promises to alert police officers to “virtually all gunfire within a city’s ShotSpotter coverage area,” enabling a fast and precise response, improved evidence collection and stronger police-community relations, according to SoundThinking, the company that owns ShotSpotter.

More than 150 cities across the country use the technology, according to ShotSpotter’s website.

But some major cities, including Chicago, Atlanta and Portland, Oregon, have decided against using the system, with city officials and others describing it as expensive, racially biased and ineffective.

Many critics see the technology as “public safety theater,” said Abené Clayton, a CNN contributor and lead reporter on The Guardian newspaper’s ‘Guns and Lies’ project.

The debate over the technology comes as the US grapples with a deadly national epidemic of gun violence. A record number of people are dying from gunshots, and guns have become the leading cause of death for children and teens – after surpassing car accidents in 2020.

ShotSpotter was founded in 1996 and developed technology that was adopted by about 20 cities, the company says. Between 2010 and 2019, it says, it improved the technology and reached the 100-customer milestone.

Despite its growth, the service is costly, “unreliable and overly susceptible to human error,” Chicago Mayor Brandon Johnson wrote on his 2023 campaign website.

CNN reached out to ShotSpotter about questions raised by Johnson over the technology’s cost and effectiveness, but a company spokesperson said they were unable to comment beyond Chicago’s contract and extension negotiations.

Company President Ralph Clark did address some broader concerns in a recent public meeting, saying, “ShotSpotter is not a perfect technology; I don’t know that any technology is perfect,” CNN affiliate WLS reported.

Police department questions price tag

The costly price tag is what fueled the Atlanta Police Department’s rejection of ShotSpotter in 2022, marking the second time the program has been rejected by the department, CNN affiliate WXIA reported.

“In its last trial in 2018, APD found ShotSpotter duplicated gunshot reports and wasn’t worth the cost of about $280,000 a year,” WXIA reported.

Meanwhile, Portland Mayor Ted Wheeler decided not to pursue the gunshot detection software for the city in June.

Instead, the mayor poured funding into a collaboration with community groups to run street-level violence intervention programs, including a gun violence reduction effort called “Portland Ceasefire,” CNN affiliate KOIN reported last summer.

Community-based violence intervention programs like Portland’s effort are proven to work, but the area lacks research and requires an investment of time to get those results, Clayton said.

“You may not know about a 12-year-old who was reached by a violence interventionist and never went on to pick up a gun, never went on to shoot somebody but could have been on that path, and I feel like that sort of stuff is rarely acknowledged or is seen as a fluke,” she said.

“Whereas something like gunshot technology just feels more concrete for people.”

How ShotSpotter technology works

ShotSpotter places 15 to 20 sensors per square mile that contain a microphone, a GPS system, memory processing and cell capability to transmit data from the location, the company’s CEO Ralph Clark told the ACLU in 2015.

The sensors record audio, monitoring around the clock for explosive noises like gunshots, he said.

When the sensors detect a potential gunshot, experts at the company’s Incident Review Center “ensure and confirm that the events are indeed gunfire,” then update the alert “with other critical intelligence such as whether a fully automatic weapon was fired or whether there are multiple shooters,” according to the company website.

Chicago Police Department members work with predictive and tracking technologies, including ShotSpotter, at the department's 11th District headquarters in 2017. - Erin Hooley/Chicago Tribune/TNS/Zuma
Chicago Police Department members work with predictive and tracking technologies, including ShotSpotter, at the department's 11th District headquarters in 2017. - Erin Hooley/Chicago Tribune/TNS/Zuma

“This entire process takes less than 60 seconds from the time of the shooting to the digital alert popping onto a screen of a computer in the 911 call center or on a patrol officer’s smartphone or mobile laptop,” according to SoundThinking.

Supporters of the system, like Chicago City Councilmember Alderman Brian Hopkins, say the technology helps police better respond to shootings that oftentimes don’t even get reported via 911.

“Say you’re home sleeping, some time around 3 a.m. you wake up to the sound of gunshots nearby,” he wrote on X. “Do you want the police to know immediately? Or would you rather they don’t know at all? 80% of gunfire incidents in Chicago are not reported to 911.”

The technology made New Jersey’s Camden County Police Department a smarter public safety agency, its police chief said over the summer, on the heels of a new $8 million technology allocation from the state.

SoundThinking claims ShotSpotter is “highly accurate at detecting outdoor gunshots,” with a 97% aggregate accuracy rate across all customers, including a very small false positive rate of less than 0.5% of all reported gunfire incidents from 2019-2021, its website says.

Alerts rarely produce evidence, Chicago official says

However, Chicago reported that police responses to ShotSpotter alerts “rarely produced evidence of a gun-related crime, rarely gave rise to investigatory stops, and even less frequently lead to the recovery of gun crime-related evidence during a stop,” according to a 2021 report from the Chicago Office of Inspector General.

Additionally, only 9% of ShotSpotter alerts in Chicago were actually gun-related crimes, the report found.

In Houston, a city that has an active ShotSpotter contract that expires in 2027, less than 5% of nearly 4,395 alerts between December 2020 and September 2022 resulted in an arrest, according to an analysis by CNN affiliate KTRK.

“The transparency isn’t necessarily there,” Clayton said. “It’s hard to give this program a lot of credit when we see so many circumstances remain the same.”

Despite those numbers, SoundThinking maintains that gun crimes are underreported, with fewer than 1 in 5 shooting incidents reported to 911. When they are reported, officers spend valuable time trying to figure out where to respond, the company says on its website.

“If 80-90% of gunfire goes unreported, why wouldn’t you want to close that gap?” Clark, the company president, wrote on X recently. “Especially, if it had the potential to save 100-plus lives in addition to other ancillary benefits. Still have not heard any reasonable argument against that proposition.”

System results in over-policing in communities of color, critics say

ShotSpotter technology is “a probable cause narrator,” Ed Vogel, a member of both the Chicago and national Stop ShotSpotter coalition – a volunteer organization for those dedicated to stopping surveillance in neighborhoods across the country, told CNN.

“There’s research that shows that the best way to address police violence is to decrease the number of times that there’s interactions between police and residents. But ShotSpotter encourages those interactions,” Vogel said.

“This technology is very intentionally being deployed in these hotspots and if you just scratch beneath the surface, it just usually translates to where poor Black and Latino people are, where violence is concentrated,” Clayton said.

ShotSpotter did not respond to questions about possible racial bias, but its website denies claims that “coverage areas are biased, lead to over-policing or potentially dangerous police deployments in Black and Latinx communities,” saying it works with local law enforcement and cities to narrow down coverage areas based on gun violence data.

The non-profit Electronic Privacy Information Center felt so strongly about that claim its lawyers asked the US Department of Justice to investigate in September 2023.

The group alleged in a letter to US Attorney General Merrick Garland that ShotSpotter targets majority-minority neighborhoods in violation of Title VI of the Civil Rights Act, which prohibits racial discrimination by any program or activity receiving federal financial assistance.

“State and local police departments around the country have used federal financial assistance to facilitate the purchase of a slew of surveillance and automated decision-making technologies, including ShotSpotter,” the letter states. “Based on publicly available information, the (Department of Justice) has awarded over $57 million in grants to local police departments through Smart Policing Programs.”

The DOJ has received the letter but – to the non-profit’s knowledge – has not acted on it, the group’s senior counsel Ben Winters told CNN.

“The cities canceling it (ShotSpotter) really reflects the myriad (of) problems with the technology, and we’re hopeful the DOJ can act to make these contract cancellations more sweeping, at least insofar as they were purchased with federal funds,” he said.

CNN has reached out to the DOJ for comment.

Chicago plans to ends ties with ShotSpotter

Chicago’s mayor outlined his plans to end the city’s ShotSpotter contract throughout his 2023 campaign “Plan for a Safer Chicago,” emphasizing his desire to strengthen police accountability.

The city’s contract expired February 16 and by the end of September the use of the technology in the city will end, a news release last week from Mayor Johnson’s office stated.

“Moving forward, the City of Chicago will deploy its resources on the most effective strategies and tactics proven to accelerate the current downward trend in violent crime,” Johnson said in the release.

Mayor Brandon Johnson answers questions during a news conference after a recent Chicago City Council meeting. - Eileen T. Meslar/Chicago Tribune/TNS/Zuma
Mayor Brandon Johnson answers questions during a news conference after a recent Chicago City Council meeting. - Eileen T. Meslar/Chicago Tribune/TNS/Zuma

Chicago started using the technology in 2018, spending $49 million for the service, averaging about $11 million per year, according to figures in an internal report from the office of Cook County State’s Attorney Kim Foxx, CNN affiliate WBBM reported.

CNN has reached out to Foxx’s office, the Chicago Police Department and the City of Chicago for further comment.

SoundThinking said the company has reached an agreement for a contract extension with the City of Chicago that allows ShotSpotter services to continue through September with an additional two-month transition period to follow, a spokesperson for SoundThinking told CNN in a statement.

“SoundThinking 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,” the statement said.

CNN’s Sara Smart and Brad Parks contributed to this report.

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