Bang, Boom, Pop — Gunshot?

Does ShotSpotter make your community safer? No, not according to the research.

SoundThinking, Inc.’s ShotSpotter platform expands the footprint of police departments without making communities safer. ShotSpotter’s technology often mistakes loud noises for gunshots, leading to more police encounters with civilians, sometimes resulting in fatal outcomes.

Research in cities to date shows:

  • ShotSpotter increases dangerous encounters between police and innocent civilians
  • ShotSpotter's contract states the technology does not prevent gun violence
  • ShotSpotter has never published results of validation testing
  • ShotSpotter refuses to cooperate with courtroom processes
View All Claims

What is ShotSpotter?

ShotSpotter has been deployed to 100+ cities and counties.

SoundThinking, Inc. is paid by cities to set up microphones in secret locations throughout neighborhoods, using triangulation technology to locate loud, impulsive noises.

  • Step 1 A loud noise is detected by ShotSpotter sensors.
  • Step 2The recording is sent to a ShotSpotter technician, who often has no scientific background or expertise, who tries to determine whether the noise is a gunshot.
  • Step 3 If the technician judges the sound to be a gunshot, the general location of the sound is published to local dispatch and/or police officers in the coverage area.

ShotSpotter has never been independently validated/tested for its ability to accurately distinguish among various loud noises. Without scientific testing, we don’t know how many impulsive sounds are incorrectly classified as gunfire.

How ShotSpotter Works

Is ShotSpotter Near You?

There are active ShotSpotter contracts in over 100 cities. Find the one closest to you.

Search below to learn more.

ShotSpotter Contract Status



Rejected / Cancelled

Noise-Detection Quiz

Which sound could cause the police to be called to your location?

Noises like these have triggered ShotSpotter alerts. Turn your sound on and take the quiz.
Choose One
  1. Firework
  2. Jackhammer
  3. Truck Door Slamming
  4. Gunshot

What ShotSpotter Claims

Claim #1

ShotSpotter claims it improves relationships between police and communities.

The Truth

ShotSpotter increases the number of high-intensity interactions between police and civilians.

Claim #2

ShotSpotter's marketing claims it reduces gun violence.

The Truth

Independent studies confirm the technology has no significant impact on gun violence. ShotSpotter’s contracts explicitly say the technology will not prevent gun violence, apprehend criminals, or lead to convictions.

Claim #3

ShotSpotter claims that 80% of gunfire incidents are never reported to police.

The Truth

ShotSpotter falsely assumes 100% of its published alerts are gunfire and further inflates this statistic by the way its system records alerts.

Claim #4

ShotSpotter claims to be a gunshot detection program that is 97% accurate with a false positive rate of less than 0.5%.

The Truth

ShotSpotter often mistakes loud noises for gunshots and has never published results of validation testing.

Claim #5

ShotSpotter claims it improves officer efficiency and evidence collection by telling them the location of gunfire.

The Truth

ShotSpotter rarely finds actionable evidence, reduces 911 calls for service, and ties up officer time.

Claim #6

ShotSpotter claims it is a forensic tool, providing forensic services and litigation support to trial attorneys.

The Truth

Public defenders confirm that ShotSpotter regularly resists subpoenas and has asked to be held in contempt of court.

Claim #7

ShotSpotter claims its technology only records “impulsive bang, boom, pops.”

The Truth

ShotSpotter has recorded more than loud sounds - it has captured voice recordings of people on the street that have been admitted as court evidence.

Shotty Statements

Responses to commonly used statements from SoundThinking's executives.

Responses to Fact-Checked Claims

Misleading Statement on Missed Gunfire

What complicates the gun violence issue further is the fact that a full 80-90% of gunfire incidents go unreported via traditional 911 calls for service. This fact has been independently documented and researched and reported on by the esteemed Brookings Institution.

Ralph Clark, CEO of SoundThinking Chicago Committee on Public Safety, November 12, 2021

ShotSpotter Statement is Not Proven or Validated.

The Brookings Institution study did not validate ShotSpotter’s ability to differentiate between loud noises. Instead, it used ShotSpotter’s self-reported alert numbers to compare against 911 calls for service.

Note: Gunshots separated by 9 seconds or more are counted as separate ShotSpotter alerts. Two gunshots 9 seconds apart would likely be perceived by a witness as one incident – they would call 911 once. ShotSpotter will use these two alerts (vs. one 911 call) to inflate their statistics of gunfire that goes unreported via 911.

Incorrect Statement on Secretly Recording Other Sounds

We only record impulsive bang, boom, pops, so we’re not recording voices and other sounds such as that.

Regan Davis, Senior Vice President, Customer Success and Field Engineering, SoundThinking Houston Public Safety and Homeland Security Committee, November 18, 2021

ShotSpotter Statement Is Historically False.

ShotSpotter sensors, which are in unknown locations, are always recording. Prosecutors have submitted audio of voices picked up from ShotSpotter recordings on at least two occasions.

Statements about “97% Accuracy” are Marketing, Not Science

It’s certainly a fact that there hasn’t been an academic peer-review of the service, but I would push back in saying it hasn’t been analyzed. It’s been analyzed for twenty years across 100+ customers that are using it every single day.

Ralph Clark, CEO of SoundThinking BBC Newsnight: ShotSpotter: What is gunshot detection technology and is it effective?

ShotSpotter Has No Independent Analysis or Testing.

ShotSpotter has never been independently validated/tested for its ability to accurately distinguish among various loud noises. Rather than test its technology, ShotSpotter starts with the assumption that 100% of its published alerts to police are gunfire and only reduces this number as officers self-report false positives (of the few departments that report, false positive rates have been as high as 48%). Legislators are willing to spend millions of taxpayer dollars on unproven tools to appear as if they are addressing gun violence.

The Human Cost of ShotSpotter

Chicago, IL

Michael Williams

Michael Williams was wrongfully arrested and charged with the murder of Safarain Herring. Prosecutors had no witnesses and no weapon - the case rested primarily upon an impulsive noise detected by ShotSpotter, which was originally labeled by the algorithm as a firework. Williams, later freed, spent nearly a year in jail, suffering from two COVID-19 infections.

Update: The MacArthur Justice Center has filed a federal lawsuit on behalf of Michael Williams, Daniel Ortiz, and Lucy Parsons Labs for “damages, declaratory, and injunctive relief on behalf of themselves and their members, and a class of similarly situated individuals in the City of Chicago who have been or will be stopped by Chicago police officers responding to a ShotSpotter alert.” The defendants are the City of Chicago, Chicago Police Superintendent David Brown, and twenty Chicago Police Department officers.

Rochester, NY

Silvon Simmons

Silvon Simmons, after being stopped in a car that was wrongly identified by police, was shot in the back by a Rochester police officer. ShotSpotter’s algorithm initially classified the noise as a helicopter, but upon a request to review by Rochester PD, ShotSpotter analysts reclassified the sounds as three gunshots and further increased the number of gunshots on two subsequent reviews (to four and five shots, respectively). SoundThinking, Inc., formerly ShotSpotter, Inc., refused to turn over the audio recordings to Simmons’ defense team for a reasonable price and Judge Christopher Ciaccio ultimately ruled the decision to convict Simmons was a mistake, in part due to the unreliability of ShotSpotter. Simmons, an innocent man, spent 18 months in jail.


Why do 100+ cities/counties use ShotSpotter if it’s so ineffective?

Technology and automation have helped society progress in so many areas of our daily lives - it’s natural for companies to try and fill that void for police even when they aren’t the solution.

Are there any privacy concerns for my constituents?

We know that ShotSpotter can record voices on the street that could later be used in court. Prosecutors have twice, to our knowledge, tried to submit voice recordings as evidence, and one of them succeeded.

What about the contracts? What are the company’s legal promises to cities?

The only promises ShotSpotter makes to cities are detection/location, the time it takes to publish an alert, and system availability.

Associated graphic

Who owns the data, ShotSpotter or the client (city/law enforcement agency)?

ShotSpotter owns the data, not the cities. ShotSpotter provides its clients with access to the data as long as the contract remains active. Further, they take steps to impede the release of data for independent research and oversight. ShotSpotter technology, paid for with public tax dollars, is often not available to the public nor easily accessible or affordable for independent research evaluations.

Latest News

In Chicago, ShotSpotter Sparks a Political Power Struggle
Michael Tercha/Chicago Tribune via AP

In Chicago, ShotSpotter Sparks a Political Power Struggle

The fight over the gunshot detection technology has escalated between the mayor and a group of alderpeople, who have tried to block its removal.
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ShotSpotter Legislation Stalls
Credit: Leigh Giangreco

ShotSpotter Legislation Stalls

In an attempt to bring back ShotSpotter, Chicago Alderperson David Moore introduced legislation that would direct the CPD superintendent (rather than the Mayor) to negotiate a gunshot-detection contract. The effort failed when Alderperson William Hall sent it to the Rules Committee, a procedure that slows (and often kills) city policy initiatives.
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The Mystery of AI Gunshot-Detection Accuracy Is Finally Unraveling
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The Mystery of AI Gunshot-Detection Accuracy Is Finally Unraveling

How accurate are gunshot detection systems, really? For years, it's been a secret, but new reports from San Jose and NYC show these systems have operated well below their advertised accuracy rates.
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Tell your local officials to #CancelShotSpotter

Tell your city/county leadership that ShotSpotter has no place in our neighborhoods. ShotSpotter does not prevent gunfire, wastes resources, and does nothing to make us safer. Gun violence is a serious problem - we demand investments in solutions, not private corporations.

These contracts can be terminated at any time. Cancel the contracts.