Chicago's ShotSpotter technology rarely leads to gun crime evidence, investigatory stops: watchdog report

A scathing report from the Office of the Inspector General raises serious questions about whether the Chicago Police Department should continue using ShotSpotter technology — the gunshot-detection service designed to locate and alert police to gunfire.

Using wireless sensors, ShotSpotter can detect gunfire and pinpoint its location with 97 percent accuracy, according to the company. Sounds like a great tool, right?

But a new report from the IG's office says the technology rarely leads to gun crimes being solved.

"If the city is to continue to invest in this technology, and to use it to make operational decisions, there should be a demonstrable law enforcement benefit to its use," said Deputy Inspector General Deborah Witzburg.


The IG's office did not find that "benefit," even after combing through almost a year and a half of CPD data. Looking at over 50,000 ShotSpotter alerts logged between January 2020 and May 2021, the IG found only 2.1 percent of the alerts led to investigative stops by police.

"We looked at what CPD's own data show, how often ShotSpotter alerts lead to recovery of evidence of gun crime, and what we found was only in a very small percentage of situations does ShotSpotter alerts do that," Witzburg.

The report also questions the quality of officers' responses to ShotSpotter alerts.

"As a result of the use of this technology, we are sending CPD members into those situations with very little information about context and what they would expect to find when they get there. That can certainly have bad outcomes," Witzburg said.

So is the city's 3-year, $33 million contract with ShotSpotter worth it?

"What we're really hoping to prompt with this analysis is a sort of sober and well-informed cost/benefit assessment," said Witzburg.

In response to this criticism, the ShotSpotter sent FOX 32 a statement which read in part, "...the Chicago Police Department continually describes ShotSpotter as an important part of their operations....the OIG report does not negatively reflect on ShotSpotter’s accuracy...nor does the OIG propose that ShotSpotter alerts are not indicative of actual gunfire whether or not physical evidence is recovered."

The company also says the IG's report is based on incomplete data.

A spokesperson for the Chicago Police Department praised ShotSpotter, calling it "crucial."

"In order to reduce gun violence, knowing where it occurs is crucial. ShotSpotter has detected hundreds of shootings that would have otherwise gone unreported," CPD said in a statement. "Using ShotSpotter, CPD receives real-time alerts of detected gunfire enabling patrol officers to arrive at a precise location of a shooting event quickly."