ShotSpotter, a gunshot detection system used by law enforcement agencies across the United States, is designed to help police identify gunfire and locate shooting incidents within seconds.

The technology uses a network of acoustic sensors, computer analysis and human review to alert police departments to suspected gunshots, including incidents that witnesses may never report to 911. Although the system has expanded across hundreds of communities and is promoted as a public safety tool, research shows that faster detection does not necessarily translate into fewer shootings or lower violent crime rates.

When Was ShotSpotter Developed?

The technology behind ShotSpotter emerged in the 1990s, when developers began exploring acoustic sensors as a way to detect and locate gunfire in urban neighborhoods. A field trial in Redwood City, California, tested the system in 1997. A report published by the U.S. Department of Justice in 1999 documented the technology's ability to detect gunfire and estimate where shots originated.

The system was developed to address a problem facing police departments: Gunshots frequently go unreported, leaving officers unaware of shootings until victims are discovered or additional evidence emerges. Traditional 911 calls can also provide incomplete or inaccurate location information, particularly when callers are frightened or unable to identify a precise address.

The technology is now marketed by parent company SoundThinking Inc., formerly known as ShotSpotter Inc.

How ShotSpotter Works

ShotSpotter relies on strategically positioned acoustic sensors installed on buildings and other structures throughout designated coverage areas. When a loud sound resembling gunfire occurs, multiple sensors capture the sound and record the precise time it reaches each device.

Specialized software analyzes the sound patterns and compares the timing of the recordings to estimate the likely location of the gunfire. The system can distinguish suspected gunshots from other loud noises, such as fireworks, vehicle backfires and construction sounds.

Human reviewers also examine potential incidents before alerts are sent to police. Once an event is classified as gunfire, the system can provide dispatchers with the estimated location, the number of shots detected and related audio information.

The process is intended to give officers a more precise starting point for responding to a shooting. However, an alert is not proof that a crime occurred, nor does it identify the person who fired a weapon.

How Many Police Departments Use ShotSpotter?

ShotSpotter has expanded substantially since its early field trials. In July 2024, a research summary published by the U.S. Department of Justice's Office of Justice Programs described the technology as being used in more than 167 cities and towns.

SoundThinking reported that ShotSpotter was serving 173 cities as of March 31, 2026. That figure provides a useful recent estimate of the system's scale, although it refers to cities rather than an independently verified count of individual police departments.

The number of participating jurisdictions changes as agencies adopt the technology, expand coverage or end contracts. Some deployments involve only selected neighborhoods rather than entire cities.

How Successful Is ShotSpotter?

The answer depends on what success means. ShotSpotter can help police locate suspected gunfire quickly, but its effect on crime reduction is less certain.

A 2024 research summary from the National Institute of Justice discussed studies in Chicago and Kansas City that found officers responding to ShotSpotter alerts were more likely to stop closer to reported gunfire locations. Researchers also found increased recovery of illegal firearms in some circumstances.

However, the research did not find that the technology reduced fatal shootings, nonfatal shootings or other firearm-related violence in the studied areas. The findings suggest that faster information and more targeted responses do not automatically prevent future crimes.

A 2025 systematic review and meta-analysis published in the American Journal of Criminal Justice examined research on acoustic gunshot detection technology. The researchers found no statistically significant overall relationship between deploying the technology and reducing crime.

These findings do not mean that every alert is inaccurate or that the system cannot help officers locate victims. They indicate that claims about broader public safety benefits require careful evaluation.

Accuracy, Costs and Public Concerns

ShotSpotter's supporters argue that the system can identify shootings that would otherwise go unreported and help officers reach victims faster. Those advantages may be particularly important in neighborhoods where residents fear retaliation or hesitate to contact police.

Critics have questioned the reliability of individual alerts, the role of human reviewers, the cost of contracts and the potential consequences of police responses in heavily monitored neighborhoods. The Associated Press reported in 2023 that human reviewers could override the system's initial classifications, raising questions about consistency and transparency.

Police departments considering the technology must weigh its potential operational benefits against financial costs, false alerts, community concerns and the need for independent performance reviews.

The Bottom Line

ShotSpotter is an established gunshot detection technology that can provide police departments with rapid information about suspected shootings. Research supports its potential to improve the precision of police responses, but current evidence does not establish that the system independently reduces gun violence.

For police leaders and city officials, the key question is not simply how many alerts the system generates. It is whether those alerts lead to measurable improvements in emergency response, victim assistance, investigations and public safety — without imposing disproportionate financial or community costs.