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ShotSpotter Study

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CSG Analysis, a police officer-owned independent commercial research firm, has published the results of its Gunshot Location System® (GLS) Efficacy Study.

Download the Shotspotter Efficacy Study here.

The independent report, endorsed by the National Organization of Black Law Enforcement Executives (NOBLE), examines the effectiveness of the ShotSpotter GLS at locating and reporting gunshots, informing investigations, increasing arrests, simplifying the jobs and increasing the safety of police officers and communities.

It specifically compares the ShotSpotter GLS to 9-1-1 in terms of the reporting of gunshots, and examines how having data produced by ShotSpotter GLS has affected the work and procedures of patrol and detectives who respond to and investigate gunshot crimes.

The report was commissioned by ShotSpotter, however CSG’s findings are independent and all transcripts, surveys and raw data on which the report’s conclusions are based are available for review.

The ShotSpotter GLS detects gunshots through acoustic sensors. Using a patented method of computer analysis,2 it provides police and public safety agency users with information and intelligence on gunfire incidents, including shot location and incident mapping, number of shots detected, and audio playback.

To create the report, CSG principals met commanders, analysts, detectives, patrol officers and dispatchers at seven US police agencies1 selected by ShotSpotter for characteristics including the length of deployment (all have had ShotSpotter for more than a year). None was compensated for participation.
Before installation, each agency indicated it had a substantial criminal gunfire problem.

Key Findings
ShotSpotter deployments increase positive community engagement with law enforcement. This led in each agency surveyed to compelling improvements in community policing, increased community responsiveness to gunfire, and a decreased sense of disenfranchisement among community stakeholders.

ShotSpotter GLS’ accuracy enables a faster response to gunfire. The accuracy of ShotSpotter GLS in pinpointing the precise location(s) from which shots were fired is critical to solving gun crimes. ShotSpotter is considered by patrol officers and agencies to be equally or more valid, and more reliable, than 9-1-1 calls from eyewitnesses or others in indicating when and where gunshot crime has occurred. This speed to response has saved lives and led to more arrests.

Patrol officers trust ShotSpotter data over 9-1-1. ShotSpotter GLS enhances patrol officers’ ability to locate the scene of a shooting more quickly and precisely, and provides more situational awareness. This helps save lives and leads to arrests. Patrol officers respond with a more tactical overall response to ShotSpotter calls. Most important, patrol officers value and trust ShotSpotter information: they trust ShotSpotter data over 9-1-1 information alone in gunfire reports, to tell them exactly when, how many, and where gunshots were fired.

ShotSpotter GLS has changed the way detectives approach homicide investigations. ShotSpotter GLS influences the decisions detectives and investigators make about where and what to search for before their arrival on-scene, and while on-scene. It also informs the types of questions they will ask of witnesses and suspects. With ShotSpotter data, detectives know empirically the number of shots fired, the time of the shots, and the location of the shots, so their initial questions can be corroborative and disqualifying in terms of witnesses and suspects.

ShotSpotter increases officer safety when responding to gunshot calls. Patrol officers respond with a more tactical overall response to gunshot calls initiated by ShotSpotter GLS activations. They universally say that ShotSpotter provides them more situational awareness to responding to gunshot calls than 9-1-1 alone, and it “Always” or “Sometimes” affects the route patrol takes to respond to gunshot calls. ShotSpotter GLS data “Often” affects the priority patrol officers assign to a call.

False positives – an activation which ultimately is determined to have been caused by something other than gunfire – are the single most common complaint of ShotSpotter users, and they pose an operational problem. They are not, however, related to the overall efficacy of the product. This report examines the cause and level of false positives and makes specific recommendations to reduce them. False negatives, an absence of a ShotSpotter activation when a gunshot is known to have occurred, are very rare and not considered an operational issue by respondents.

ShotSpotter provides agencies with better crime data. Since many gunshots are not reported to 9-1-1, ShotSpotter GLS allows cities to better understand the true level of gunfire in their communities. This effect is most beneficial in agencies which engage in rigorous “cleaning” of ShotSpotter activation data.

Finally, the report considers ways in which agencies may get better value from their ShotSpotter deployment by introducing new workflow management and best practices. Implementing these would result in more strategic use of ShotSpotter to inform Intelligence-Led Policing, Neighborhood and Community Policing, and other important policing, law enforcement and crime reduction initiatives.

If you have comments or questions about the report, our methods or findings, please use our contact form.

Download the Shotspotter Efficacy Study here. The study is distributed under the Creative Commons Attribution-Non Commercial-ShareAlike 3.0 Unported License.

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