More Cities Are Moving to Drop Automated Gunshot-Detection Tech

Experts say ShotSpotter is unreliable and disproportionately calls armed police into Black and brown neighborhoods.
A police car behind yellow caution tape
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Community organizers in San Diego and Chicago are calling on their city leaders to end contracts with the surveillance company ShotSpotter, which installs hidden microphone arrays and uses a combination of algorithms and human reviewers to detect gunshots. 

Recent Motherboard investigations found that in at least four cities, the tech is placed almost exclusively in non-white neighborhoods, and that ShotSpotter analysts who prepare forensic reports for criminal trials have changed the the system’s original findings about the number and location of gunshots—sometimes in ways that support police narratives that aren’t backed by any physical evidence. (Police and Shotspotter both claim the system is installed in "high-crime" areas.) It is currently in place in more than 120 cities, including a more than 117-square mile swath of Chicago and a 3.6-square mile area in San Diego. 


The contracts in San Diego and Chicago are soon set to expire and some residents in the affected communities are fighting back against the technology.

The San Diego City Council was scheduled to vote July 27 on a $1.15 million renewal of its ShotSpotter contract, but city officials withdrew the item from the agenda after dozens of residents submitted public comments opposing the contract.

“ShotSpotter is a perfect example of the patronizing approach to public safety in Black and brown neighborhoods—this idea that we know what’s best for Black and brown community members,” Khalid Alexander, president of Pillars of the Community, told Motherboard. Pillars is an organization that opposes the over-policing of Black and brown residents, and is based in San Diego’s District 4—the only area of the city where ShotSpotter is located.

“I haven’t heard one person in District 4 ... come out and say that the ShotSpotter technology is something needed to keep us safe,” Alexander said.

In a statement emailed to Motherboard, ShotSpotter claimed that local communities have told them the opposite, and that it would be "false and misleading" to describe the activists as representing the larger population. "As the communities who suffer most from gun violence, they recognize and appreciate ShotSpotter’s role helping police departments combat gun violence,” the company wrote.


The company pointed to a 2020 survey of 121 residents in Cincinnati, administered six months after ShotSpotter was installed. It found that 95 percent of them believed the technology was an effective way to fight crime, but also that 61 percent said it increased their own fear of being arrested.

Notably, the survey’s respondents were more than 90 percent white. The study was also entirely funded by ShotSpotter and the Cincinnati Police Department, Cory Haberman, the University of Cincinnati criminal justice professor who conducted the survey, told Motherboard.

In Chicago, a coalition of community groups and residents gathered Thursday from the spot where police—dispatched to the scene following a ShotSpotter alert— shot and killed 13-year-old Adam Toledo. They marched to the offices of Ward 22 Alderman Mike Rodriguez, who they said has refused to join their fight against ShotSpotter. 

Rodriguez did not respond to a request for comment by the time of publication.

“These ShotSpotter alerts are sending police into our communities with the intent that there’s danger. When they get to that location, they’re going to stop the first Black or brown teen they see, and they’re not going to do it nicely,” Jose Manuel Almanza, a community organizer with Unete, a neighborhood advocacy group in Little Village, Chicago, told Motherboard. “There’s all these things that we could be using this money for instead of doing the same old thing and feeding the same old institution.”


ShotSpotter’s current three-year, $33 million contract with Chicago is set to expire in August. 

In a statement to Motherboard, Chicago Police Department spokesperson Tom Ahern defended the department’s use of the technology, citing a “historically low rate of 911 calls” reporting shootings in the city. ShotSpotter helps police “respond more quickly to locate and aid victims, identify witnesses, and collect forensic evidence. The system gives police the opportunity to reassure communities that law enforcement is there to serve and protect them and helps to build bridges with residents,” he wrote.

San Diego city officials did not respond to requests for comment. In a statement to the local NBC station after his administration pulled the ShotSpotter renewal vote from the City Council agenda, Mayor Todd Gloria described ShotSpotter as a “valuable tool.” He added, however, that the city was considering removing the sensors from San Diego’s District 4 at the request of the councilmember who represents the district.

"We have every intent to bring the item back to the city council and explore its use into other neighborhoods of the city," he told NBC.

In both San Diego and Chicago, police data has raised questions about the technology’s efficacy and whether it’s worth multi-million dollar contracts.


A San Diego Police Department spokesperson told Voice of San Diego that during the four years ShotSpotter had been in use (as of September 2020) officers had made only two arrests responding to an alert and only one of those was directly linked to the alert. 

Meanwhile, 72 of the 584 ShotSpotter alerts during that time period were determined to be unfounded, “a whopping 25 times higher than the 0.5 percent false positive rate put forth by the company,” the Voice of San Diego reported, based on data provided by the city’s police department. ShotSpotter told the Voice of San Diego that its data is a national average, and that it relies on police departments to report false positives.

In Chicago, the MacArthur Justice Center recently released a study that found police did not file a report of a crime in 86 percent of the cases initiated by a ShotSpotter alert.

ShotSpotter has aggressively pushed back against that study, recently paying a private research firm, Edgeworth Analytics, to try and debunk it. The Edgeworth report states that the MacArthur Justice Center study is “severely flawed” because the data it used does not take into account police reports about shootings that can’t be linked to specific ShotSpotter alerts or that come well after officers have cleared the scene of an alert. 

“The lack of physical evidence of a gunfire event, such as a victim, shell casings, or bullet holes, does not mean a gunfire event didn’t take place,” ShotSpotter wrote.

Should San Diego or Chicago officials choose not to renew their contracts with ShotSpotter, they would join San Antonio, Texas; Troy, New York; Charlotte, North Carolina; Fall River, Massachusetts; Trenton, New Jersey; and other former customers in cutting ties with the company.