ShotSpotter gunfire detection system

ShotSpotter is an acoustic gunfire detection system manufactured by US-based company SoundThinking (named ShotSpotter until April 2023). Consisting of microphones, sensors, algorithms, and human reviewers, the system alerts police to potential gunfire.

ShotSpotter has been used by multiple municipal authorities, police departments and school districts across the US since 1997, and has been used as evidence in legal trials. 

According to Chicago mayor Lori Lightfoot, ShotSpotter 'plays an important role' in saving lives. 

Operator: Chicago Police Department; Houston Police Department; New York Police Department
Developer: SoundThinking/ShotSpotter
Country: USA
Sector: Govt - police
Purpose: Detect gunfire
Technology: Gunshot detection system
Issue: Accuracy/reliability; Bias/discrimination - race, ethnicity, income, location; Effectiveness/value; Oversight/review; Robustness
Transparency: Governance; Black box; Marketing; Legal

Risks and harms 🛑

ShotSpotter has proved controversial, with concerns expressed about its accuracy, reliability, effectiveness, bias, fairness and impact on privacy. SoundThinking has also been accused of misleading marketing and displaying poor transparency and inadequate accountability.


SoundThinking claims 97 percent accuracy and 0.5 percent false positive rates across its ShotSpotter customers. But a number of incidents and third-party studies undermined the claim, raising questions about the system's effectiveness and value. 


Questions have been asked about the degree to which human analysts assess and modify ShotSpotter alerts.


ShotSpotter has been accused of discrimination against minority communities. 


Civil liberty and privacy advocates have expressed concerns about the use of ShotSpotter microphones and sensors in public spaces and their proximity to housing, and worry that it may set a poor precendent. 

Concerns have also been expressed about the length of time aural data is retained by SoundThinking, and how secure it is.

Transparency 🙈

Investigations, assessments, audits 🧐

Page info
Type: System
Published: May 2022
Last updated: May 2024