HOUSTON – The Harris County Sheriff’s Office is now using technology to automatically detect the sound of gunshots in northeast Harris County.
HCSO would not pinpoint specifically where the technology is being used, but told KPRC 2 Investigates that the detection system, which has been alerted over 4,000 times since May 31, 2021, covers a five sq. mile area in the Aldine area.
“We have made several arrests, 40 new charges as a result of the shot spotter. (The arrests) ranges from aggravated assault to, you know, a felon in possession of a weapon,” said HCSO Major Tommy Diaz.
Diaz said deputies are dispatched “priority one,” with lights and sirens when a shot spotter call comes in, and the arrival time is cut in half versus traditional dispatching.
He also said the technology is helping to build a map of where incidents are happening, which will, in turn, lead to better law enforcement coverage and safer neighborhoods.
Other cities, including San Antonio and Chicago, have deemed the equipment ineffective.
The ACLU notes the technology is often deployed in “communities of color.”
KPRC 2 Investigates asked the shot spotter a series of questions via email, here’s how they responded:
How does ShotSpotter gunshot detection technology work?
ShotSpotter sets up an array of acoustic sensors in a coverage area on top of buildings or light poles. These sensors listen for loud, impulsive sounds that may be gunfire. Once captured, ShotSpotter’s computers dismiss sounds that are clearly not gunfire such as fireworks or helicopters. The remaining sounds are sent to specially-trained ShotSpotter reviewers located in our ShotSpotter Incident Review Centers (“IRCs”), who then playback the recorded sounds and visually analyze the audio waveforms to see if they match the typical pattern of gunfire, assess the grouping of sensors that participated, and either publish the incident to police as gunfire or dismiss it as non-gunfire. This entire process typically occurs within 60 seconds from the time of the gunfire to the time the alert is sent to law enforcement. Here is a video that also explains the technology: https://youtu.be/Nk980tdlzFI
Can you show us what the equipment looks like?
No, we cannot provide a photo, but the ShotSpotter media kit has videos and diagrams available. You can find the media kit here: https://www.shotspotter.com/media-kit/.
Can you provide any metrics in terms of accuracy and success?
More than 80% of gunfire incidents are not reported to police, per the Brookings Institution. ShotSpotter fills that data gap by alerting police of virtually all gunfire within 60 seconds. This enables a fast, precise police response to help save the lives of gunshot wound victims and capture critical evidence at the scene.ShotSpotter is trusted by more than 120 cities and police departments across the country have reported success with ShotSpotter, which can be seen on our Results Page and in our published Success Stories. The ShotSpotter system is highly accurate as it operates at a 97% aggregate accuracy rate for real-time detections across all customers. Derived directly from police department reports submitted to ShotSpotter, this accuracy rate was independently verified by Edgeworth Analytics, a data science firm. You can find the Edgeworth report here: https://edgeworthanalytics.com/independent-audit-of-the-shotspotter-accuracy/
San Antonio discontinued the use of this technology because it failed to recognize 5 gun-related homicides in a shot spotter coverage area… why did the technology fail in that case?
ShotSpotter is not able to comment on specific contracts, but the system is trusted by police departments in over 120 cities, has a customer retention rate greater than 98%, and has an expansion rate greater than 60%. Across all of the cities we serve, including cities in Texas, our customers have seen success with the ShotSpotter system. For example, Houston, TX - Local law enforcement agencies reaping benefits of new gunfire detection system (2021)Gunshot detection system leads deputies to N Harris Co. marijuana grow house (2021)Rocky Mount, NC: Latest report shows crime decreased in August (2021)Youngstown, OH: COVER STORY [VIDEO]: SHOTSPOTTER PROVIDES QUICK RESPONSE (2021)Chicago: Dep. Mayor of Public Safety on ShotSpotter: ‘The technology is extremely accurate, which always leads to a response from CPD’(2021)For more results, you can visit the ShotSpotter results page here.
A Chicago OIG report was also critical of the technology.. saying, in part, that your system rarely leads to collect evidence of a crime, how do you respond to that?
https://igchicago.org/2021/08/24/oig-finds-that-shotspotter-alerts-rarely-lead-to-evidence-of-a-gun-related-crime-and-that-presence-of-the-technology-changes-police-behavior/The Chicago Police Department continually describes ShotSpotter as an important part of their operations. The OIG report did not specifically suggest that ShotSpotter alerts are not indicative of actual gunfire whether or not a police report is filed or physical evidence is recovered. It is important to note that traditional 911 calls for service from community members during this same time period resulted in a police report or evidence found in only 16 percent of incidents, no better than ShotSpotter alerts at 17 percent, and there is universal agreement about the value of the 911 system. ShotSpotter’s accuracy has been independently audited at 97 percent based on feedback from more than 120 customers.
ADDITIONAL BACKGROUND INFORMATION (provided by ShotSpotter): Here is an independent privacy audit conducted by NYU’s Policing Project that concluded that the risk of voice surveillance by ShotSpotter is extremely limited. Strict controls and policies ensure sensors only trigger loud explosive or impulsive sounds that are likely gunfire. No community member’s information is obtained or used during any part of the detection or alerting process. To learn more about ShotSpotter’s review process, please find a Medium piece recently published by ShotSpotter President and CEO, Ralph A. Clark, that includes helpful information on the machine learning classification and the human review process. Here are a few additional studies/reports that may also be helpful:
- According to independent research by Dr. Anna Goldenberg-Sandau (an attending trauma surgeon who specializes in critical care medicine, general surgery, and traumatic surgery at Cooper University Hospital in Camden, New Jersey) and a team of other medical/health professionals, ShotSpotter helps first responders identify and assist gunshot victims who would otherwise not receive life-saving help.
- Real-Time Crime Centers in Chicago (Evaluation of the Chicago Police Department’s Strategic Decision Support Centers)
- The Rand Corporation “statistically assessed the impacts of adding [Strategic Decision Support Centers] (SDSCs) for their principal objective: reducing crime. SDSCS was found in his experiment to be effective, overall, at reducing crime. In 40 models, districts’ average monthly crime counts declined after adding an SDSC, albeit to a significant extent in 215 models (38 percent)…” (SDSC’s are video surveillance, ShotSpotter Connect and ShotSpotter Respond, geo-spatial mapping software, and localized resources at the District Level analyzing and responding to crime (problem-oriented policing).
Here are some examples of ShotSpotter’s effectiveness (provided by ShotSpotter):
- In Oakland, California, 101 gunshot wound victims were found and aided by police due to ShotSpotter alerts when no one called 911.
- Pittsburgh, Pennsylvania reported a 36 percent drop in homicides year-on-year in 2018 and 2019, continuing a downward trend over five years.
- In 2019, Greenville, North Carolina experienced a 29 percent reduction in gun violence injuries and a 20 percent reduction in homicides in the first year of ShotSpotter deployment.
- In April, Chicago police were alerted to the scene of a shooting by ShotSpotter and were able to save a 13-year-old boy’s life. Without ShotSpotter, police may never have found him.