The more we learn about ShotSpotter, the gunfire-detection system, the less impressive it seems.
The latest salvo comes from the Associated Press, which has now reported that ShotSpotter employees can listen to information gathered by the technology’s outdoor listening posts and have the power to decide if a sound is a gunshot or not — overruling the algorithm’s determination.
The reversals happen 10% of the time, according to the AP report.
On one hand, it sounds reassuring that actual humans have been placed in the mix in hopes of insuring ShotSpotter’s accuracy.
But we also see it as yet another flaw with the high-priced system. It was sold to the Chicago Police (and other departments more than 140 cities) as a law enforcement tool that is accurate and technologically-advanced — with heavy emphasis on the ‘technology’ part — but time and again, it has proven to be considerably less-than-advertised.
Might be a gunshot, might be a ‘ping’
ShotSpotter’s tech is supposed to recognize gunfire and then provide police with an approximate location of the weapon’s alleged discharge.
But an internal document obtained by the AP stated that ShotSpotter employees “are given broad discretion to decide if a sound is a gunshot, fireworks, thunder or something else.”
Montana State University professor Robert Maher, a national expert on gunshot detection, told the AP, “I’ve listened to a lot of gunshot recordings — and it is not easy to do.
“Sometimes it is obviously a gunshot,” said Maher, who reviewed the Shotspotter document. “Sometimes it is just a ping, ping, ping ... and you can convince yourself it is a gunshot.”
Add that to ShotSpotter’s own expert, who testified in a 2021 San Francisco trial that the technology’s accuracy is affected by topography, temperature, humidity, wind speed and how often the equipment is calibrated — and also the skill of the humans interpreting the sounds picked up by the monitors.
ShotSpotter defended its technology.
“Our data, based on the review of millions of incidents, proves that human review adds value, accuracy and consistency to a review process that our customers — and many gunshot victims — depend on,” Tom Chittum, the company’s vice president of analytics and forensic services, told the AP.
The $11 million a year question
Has ShotSpotter been useful on occasion? Certainly. For instance, last New Year’s Day, gunshot detectors led police to 56th Street and Prairie Avenue, where they found a car that contained one teen shot to death and three others wounded.
In a city plagued by shootings, in theory every little bit helps. But how much is ShotSpotter really helping, especially at its price?
We wonder. Especially in light of a 2021 report by the city’s Office of the Inspector General.
The report found Shotspotter “alerts rarely produce documented evidence of a gun-related crime, investigatory stop, or recovery of a firearm.”
That echoes conclusions drawn last fall by the Dayton, Ohio police department when it decided not to renew a three-year, $615,000 ShotSpotter contract.
“[I]t is challenging to develop statistics showing how effective ShotSpotter would be on its own,” Dayton Police said in a statement. “While the ShotSpotter area shows a more considerable decrease in violent crimes, this cannot be solely attributed to ShotSpotter’s effectiveness, as it was only one of the many tools used to combat violent crime in this area during this timeframe.”
Given all that, is ShotSpotter better or more accurate than 911 calls from the public? And if so, is it $11 million a year — the amount the Chicago Police Department spends yearly on Shotspotter — better?
These are the hard questions police and Mayor Lori Lightfoot should ask before ultimately considering another multi-million dollar re-up of the program.
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