St. Paul asks: So, does ShotSpotter actually work?

St. Paul Mayor Melvin Carter and City Council Member Dai Thao got into a tense exchange this week on whether a computer system that tracks gunfire could help protect the city.

St. Paul Mayor Melvin Carter and City Council Member Dai Thao got into a tense exchange this week on whether a computer system that tracks gunfire could help protect the city. Twitter

St. Paul is having a record year for gun violence, in a bad way, with 26 out of 29 homicides this year involving firearms.

The numbers are arresting figures on their own. On Wednesday, St. Paul City Council Member Dai Thao made things personal.

“I want to just ask you, do you think that my kids are important to you?” he asked Mayor Melvin Carter.

“Excuse me?” Carter replied.

Thao repeated the question, asking if Carter thought the council member’s kids mattered. The two talked over one another for a moment or two before Carter cut Thao off.

“Council member, you asked a question,” he said. “Would you like the answer?”

As soon became clear, Carter and Thao were talking about ShotSpotter, a computer program that relies on a network of outdoor microphones tuned to the sounds of gunfire. Recorded gunshots turn into points on a map, in theory to help officers respond to the sound whether residents report it or not. (As has been observed in cities affected by gun violence, they often don’t.)

Thao wants to deploy ShotSpotter in St. Paul, but Carter has misgivings without an “independent, third-party evaluation” showing ShotSpotter is actually effective.

“If you can produce that," Carter told Thao, "I would love to reconsider and revisit that topic. But I think it would be a mistake for us to confuse buying one particular toy with reducing gun violence in our community…. We as a community owe it to ourselves [and] to your beautiful children that when we spend a million dollars on public safety investments, that it actually makes us safer.”

The address was punctuated with applause and generally deemed a solid hit by people reacting online. You can watch the clip captured by Wedge LIVE! here… albeit with some editorialization about Thao.

Carter isn’t the first person to ask if ShotSpotter even works. It’s being used in just shy of 100 cities across the country, and law enforcement, researchers, and public officials still haven’t quite figured out how to answer that question.

As a 2016 piece by Forbes pointed out, the technology is usually pretty reliable, with occasional false alarms involving fireworks and backfiring cars. The more important test of its worth is whether it reduces gun violence. Some hard-won data from seven cities using the technology found the “clear pattern” was “lots of calls, but few tangible results.”

“Of the thousands of ShotSpotter alerts in these cities, police were unable to find evidence of gunshots between 30 to 70 percent of the time,” Forbes reported. “The question now is whether the technology is worth the millions of dollars it’s costing taxpayers each year, and if the lack of tangible results is because we don’t have the ability to measure them, or that they simply don’t exist.”

But ShotSpotter has its fair share of “happy customers,” as reported by Time magazine in 2017.  Police in Omaha told the magazine that ShotSpotter had aided in reducing gunfire by 45 percent since 2013. A New York Police Department specialist called it “one of [their] most successful programs.” Police in Milwaukee said in 2015 alone, 4,300 ShotSpotter alerts led to recovering more than 2,600 shell casings and leading to 68 arrests. There is powerful anecdotal evidence of the tech's potential.

To skeptics like Carter, ShotSpotter's yet to prove its effectiveness. In his argument last week, Carter cited a research piece in Police Chief Magazine on "acoustic gunshot detection systems" (AGDS), which studied the use of ShotSpotter in St. Louis.

The report suggested the positive view of ShotSpotter and its technological peers might have been more due to a “broad downward slide in crime that has taken place since the 1990s” and “a few highly publicized cases” instead of the program's own merits.

“Results show that AGDS simply seem to replace traditional calls for service and do so less efficiently and at a greater monetary cost to departments,” it said. But: “To be fair, the current study examines only St. Louis, and results might differ in places with a dissimilar policing context.”

It’s that last sentiment that Thao points to as evidence to give ShotSpotter a try.

“We should be independent and collect our own data,” he says. He points to the fact that Minneapolis has been using ShotSpotter since 2007, and that the state may be willing to offer a substantial grant to offset the cost. (Emails between the mayor and Police Chief Todd Axtell obtained by KSTP say that Axtell estimated the cost of the tech at $750,000, and that the state would be willing to foot $500,000 of that bill.)

“I think it’s normal for people when they’ve already made a decision to find the arguments against [an idea],” Thao says. “But that’s not the full story.”

Carter wasn't available for an interview, but spokesperson Peter Leggett sent a statement saying Carter had proposed a "portfolio of investments, rooted in data and evidence, to reduce violent crime and hold offenders accountable." 

"As the mayor has repeatedly said, this administration will consider every proven tool to effectively achieve these goals," he said.

It’s probably not the last we’ll hear about ShotSpotter in St. Paul. As Thao said, it’s ultimately Carter’s decision whether to invest in the program, but he’s hoping an “informed” public will put some external pressure on the issue.