Chicago watchdog concludes ShotSpotter 'rarely' finds gun crime

Occurred: August 2021

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Chicago's Inspector General issued a report saying that the use of the ShotSpotter gunfire detection system by the city's police  'rarely produce[s] documented evidence of a gun-related crime, investigatory stop, or recovery of a firearm'. 

Having analysed 50,176 ShotSpotter notifications from January 2020 to May 2021, the Inspector General found (pdf) 9.1 percent indicated evidence of a gun-related offence was found, and 2.1 percent of the alerts were linked directly to investigative stops. 

The report also questioned the 'operational value' of the system and, based at least in part on aggregate ShotSpotter data, found that it increased the incidence of stop and frisk tactics by police officers in some neighbourhoods. This pattern was criticised by the Electronic Frontier Foundation as 'a dangerous and humiliating intrusion on bodily autonomy and freedom of movement.'

In February 2024, Chicago announced it would not renew its three-year, USD 33 million contract with ShotSpotter and would stop using the system in September 2024.


Operator: Chicago Police Department
Developer: SoundThinking
Country: USA
Sector: Govt - police
Purpose: Detect gunfire
Technology: Gunshot detection system; Deep learning; Neural network; Machine learning
Issue: Accuracy/reliability; Effectiveness/value; Robustness
Transparency: Governance; Black box