PORTLAND, Ore. (KOIN) – After a rise in gun violence in Portland in recent years, the community oversight group for the Portland Police Bureau is likely to recommend a controversial gunshot surveillance system to City Council.

ShotSpotter is a technology that is currently used in 100 or more cities and counties. The idea is to detect gunshots and get police out to the scene as soon as possible.

ShotSpotter has been on the market for two decades. The technology attaches microphones to light poles, with gunshot sensors that immediately alert police to a shooting.

Jonathan Manes, an attorney at the MacArthur Justice Center in Chicago, has collected data on ShotSpotter for a year and a half. Their study focused on the unjustified police deployments and the racially disparate deployment of ShotSpotter.

“There’s no evidence that it’s reducing gun crime,” Manes said. “They’ve never tested the system to see how easily it’s fooled by things like fireworks or things like cars driving over potholes or cars backfiring. So, we don’t have any scientific evidence about how good it is at telling gunshots apart from other noises.”

His research found that about nine out of ten times when police respond to an alert from ShotSpotter, officers do not find evidence of any gunfire or a gun.

“The trouble is that they might run into residents who happen to just be in the wrong place at the wrong time. And this has led to many hostile encounters stops and frisks, and unjustified arrests,” Manes said.

These deployments also come at a cost. The researcher points to other cities such as Atlanta which found that it cost them $56,000 per arrest. In Houston, only 2% of ShotSpotter deployments led to an arrest.

Chicago Office of Inspector General study showing that only 9.1% of ShotSpotter alerts lead police to find anything relating to guns or gunfire.

“It’s not cost-effective and it causes harm,” Manes said.

Doucette, et al (Johns Hopkins) study of 68 counties with ShotSpotter showing no reduction in firearm homicides, murder arrests, or weapons arrests.

Portland police’s community oversight group wants to bring ShotSpotter to City Council to consider as a tool to tackle gun violence. 

Though the community oversight group acknowledges that ShotSpotter is not perfect, FITCOG Chair Ed Williams said “we hear both the kudos and criticisms of the technology. You tell me when you find the one that’s absolutely 100% drop dead perfect and I’ll be glad to listen to that.”

The oversight group created a comprehensive list of conditions regarding equity and justice that must go along with the use of the technology if the City of Portland were to decide to move forward.

“We’ve written this recommendation so that it is inclusive of many of those concerns that we’ve heard,” Williams explained.

While there is an impulse to address gun violence, critics warn there is no technological silver bullet to end this crisis.

In a statement to KOIN 6 News, ShotSpotter explained “the ShotSpotter system is highly accurate. Our service-level agreement guarantees that 90% of unsuppressed, outdoor gunfire incidents, using standard, commercially available rounds greater than .25 caliber, inside the coverage area, will be detected and located within 82 feet of the actual gunshot.”

The company added “over the years, ShotSpotter and police departments have conducted live-fire testing of their gunshot detection systems including a publicly documented live-fire test in Pittsburgh, PA showing that the system detected 100% of incidents and located 96.9% of incidents within a 25-meter benchmark criterion. However, the ultimate test is the evaluation ShotSpotter withstands thousands of times a day when it sends alerts to law enforcement agencies nationwide who report back their results. ShotSpotter has a 97% aggregate accuracy rate across the customer base between 2019 and 2021, that has been independently verified by Edgeworth Analytics. These results in addition to our 98% customer retention rate indicate that the system works well.”

However, Manes said the 97% figure is not an accurate statistic.

“That’s a misleading and deceptive,” he said. “They assume that every alert is a gunshot. They just assume it. And they only count something as an error if the police send them a complaint about a particular alert that they it wrong. So it’s a tally of customer complaints.

The community oversight group is slated to meet Thursday to further discuss the recommendation.