Some cities are ditching ShotSpotter. Tacoma still wants the gunshot detection technology

Tacoma plans to install acoustic gunshot detection technology this spring in an area that has been the site of several homicides in recent years. But not everyone is convinced the ShotSpotter system will lead to a reduction in gun-related crimes.

The Tacoma Police Department will pilot ShotSpotter in a two-mile area in South Tacoma around Hosmer Street, which has been called Tacoma’s “deadliest” street. The city has identified the area as an outlier, as violent crime has trended downward in Tacoma since a peak in 2022.

“By reducing response times and alerting officers to gunfire incidents that might otherwise go unreported, ShotSpotter has the potential to save lives while minimizing over-policing,” a spokesperson for the Tacoma Police Department said in a statement.

ShotSpotter is one of three technologies funded by an $800,000 grant from the Bureau of Justice Assistance that Tacoma is adopting to improve its ability to investigate gun crimes.

“Could we reduce crime in Tacoma, without causing harm? That’s the principle,” Tacoma Police Chief Avery Moore said during a presentation on the department’s violent crime reduction plan at a City Council meeting in October. “You can take that principle and you can apply it to any strategy we have when it comes to reducing crime.”

How it works

ShotSpotter sets up a series of acoustic microphone sensors, generally in areas identified by cities as experiencing high gun crime.

“They wait for that dynamic event, a bang, boom, or a pop, and then from there, a location-based server sends information to a classifier,” explained Alfred Lewers Jr., senior director of trauma response and community engagement at SoundThinking, the company that makes ShotSpotter.

The sound file travels to a human in an office in either Washington, D.C., or California, who listens and validates whether a gunshot has been detected. If so, the person informs police and gives them the location by triangulating the sensor data.

“That all happens in 60 seconds or less along with a historical Google map image with an 82-foot or 25-meter halo showing where the gunfire event occurred, and a sound file,” Lewers Jr. said.

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The idea is to identify gunshots more quickly and with more precise location information than 911 calls, allowing police to respond faster, gather more evidence, and solve more crimes.

SoundThinking claims ShotSpotter has been used in more than 180 cities around the world.

Not so fast

But the technology has been at the center of debate in several major cities. Critics say it doesn’t live up to promises of improving investigations and reducing crime. Houston’s mayor called ShotSpotter a “gimmick” when he announced plans last May to scrap the city’s contract. Chicago ended its use of ShotSpotter last fall.

In Seattle, Mayor Bruce Harrell advocated for using acoustic gunshot detection technology before backing off of plans for a pilot program last year.

Community advocates in Tacoma said they worry ShotSpotter will lead to more law enforcement surveillance in communities that have long suffered from over-policing.

They say the technology isn’t worth investing in because it doesn’t address the underlying problem that leads to gun-related crimes.

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Latasha Palmer, community advocate and board secretary of the Hilltop Action Coalition, said technology like ShotSpotter is primarily placed in Black and brown neighborhoods and has the effect of bringing police into the area believing violence has already occurred.

“They get dispatched for things like backfires on cars and fireworks,” Palmer said. “If we're going to put money towards something to get at the root of this safety issue, then it should be something that is going to actually solve the problem.”

Bunchy Carter, minister of defense for the Black Panther Party in Tacoma, said money to prevent gun violence should have gone not to the Tacoma Police but to organizations that are working with people in South Tacoma and local businesses struggling to stay afloat.

“You could have taken that and helped some of these businesses stay in business and utilize that money to create training programs to teach people the skills that they need to do the job,” Carter said. “That's how you keep people from picking guns up.”

Is ShotSpotter effective?

Eric Piza, a professor of criminology and criminal justice at Northeastern University in Boston, leads a team of researchers who have looked at 15 years of ShotSpotter data in Chicago and Kansas City.

The data shows improved police and EMT response times but also an increase in “unfounded” calls compared to 911.

Piza and his team found that ShotSpotter did not increase racial disparities in police response, but it also did not lead to a reduction in gun violence in either Chicago or Kansas City.

Tacoma Police promise independent academic experts will look at ShotSpotter’s effect on evidence gathering and response times.

“We will thoroughly evaluate the technology’s effectiveness, as well as evaluate the impact on the community,” TPD said in a statement. “If we find the use of the technology is not consistent with the guiding principle or if there are unintended consequences from its use, TPD will immediately cease the use of the technology.”

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Lewers Jr. of SoundThinking, ShotSpotter’s parent company, said he welcomes scrutiny of the technology and believes ShotSpotter could be a great benefit to Tacoma Police.

“They want to improve their response time to gunfire events,” Lewers Jr. said. “They want better insight. They want to be able to save lives. They want to be able to collect more evidence. And they want to make sure that they're appropriately serving their community.”