Amplifying School Security With Gunshot Detection Systems

Solutions Can Speed Response to the Threat

Rich Onofrio headshot
Rich Onofrio is the chief technology officer for Shooter Detection Systems.

Gun violence in American schools is a topic that no one likes to think about, much less discuss. Preventive measures should be priorities, including security practices and technologies, and resources should be provided to help students and staff deal with mental health and anger issues before they escalate. But schools must also prepare for when these efforts are not enough.

Nearly 60% of active shooter incidents at educational institutions since Columbine in 1999 have occurred in high schools, and about 21% have occurred in middle schools or junior high schools. The remainder have happened in elementary schools, K-8 schools and K-12 schools. The number of individuals killed or injured in school shootings in 2023 was more than double the number of casualties in 1999.

Gunshot detection systems have emerged as a meaningful component of a comprehensive security strategy that can have a significant impact on the outcome of active shooter incidents. These systems can be leveraged to quickly alert everyone of a dangerous situation, enabling them to react and respond before it is too late.

The Limitations of Current Response Systems

During gun violence incidents, knowing exactly where the incident is happening in real time is critical so that building occupants can quickly get to safety and first responders can rapidly mitigate the threat.

At Virginia Tech in 2007, an active shooter managed to go undetected for two and a half hours after his first two shots were fired in a dormitory. He later shot 47 people that he locked inside of an academic hall. After this incident, the implementation of more robust mass notification systems became commonplace. However, these systems often rely on human action to trigger them, which can result in errors and delays, highlighting the need for better technological solutions.

The premise behind gunshot detection is that the system will alert first responders faster than any current method so that they can get to the scene faster, armed with critical incident details they might not otherwise have. Providing vital location information, including where in the building the incident is happening, cuts through typical alert delays and enables a more immediate response to be initiated. To maximize effectiveness, a gunshot detection system should be capable of sending real-time data and updates to 911 operators – and it must be reliable enough that law enforcement agencies will accept the technology into their workflow.

Both speed and accuracy are paramount. The average length of an active shooter incident is around five minutes, with an average of one death occurring every 5 to 15 seconds while active shooting is taking place. Ultimately, a school needs to be able to rely on the gunshot detection system to automate the alerting process as early as possible and with the highest level of accuracy to make a real impact.

When integrated with other technologies already in many schools, such as video surveillance, metal detectors and electronic locks, gunshot detection systems provide a crucial layer of detection that can instantly alert staff if a determined shooter is undeterred by other countermeasures. This layered approach is recommended by leading school safety organizations, such as the Partner Alliance for Safer Schools and is included in the Cybersecurity and Infrastructure Security Agency’s Guidelines for School Safety. 

A Guide to Evaluating Systems

Much like other security technologies, not all gunshot sensors and alerting systems are created equal. At their core, indoor gunshot detection systems include one or more sensors, strategically positioned within a facility, that transmit gunshot alerts through a communications platform.

When evaluating sensor types, it is important to understand how the sensor functions. The simplest approach is to ask some very basic questions: How is a gunshot identified? How is the information getting to key stakeholders on campus? How long does that take? Is the information accurate?

Acoustic-Only Solutions

It is not technically difficult to simply place a microphone on a wall and calibrate it to detect an acoustic signature that meets a certain criterion. This approach, however, will lead to a high number of false alerts.

Multimode Solutions

Since every gunshot creates both an acoustic signature (bang) and an infrared signal (flash) (including most suppressed weapons), a sensor that uses both signals to detect shots will be the most effective. If a vendor claims to detect a gunshot through a physical barrier (like a wall), it is likely the system is not using the infrared signal to assess the event. The infrared flash should be detectable even if the shooter is not in the line of sight of the sensor – for example, is facing away from it.


Some sensors require calibration to the environment. For example, a calibration-required sensor in a large gymnasium may need a different setting than one in a school lobby. Manual calibration involves close monitoring and analysis before sensors are fine-tuned to sounds in the environment. A plug-and-play sensor that does not require calibration will be the most reliable and will be less susceptible to human error.

External Validation

Systems that rely on acoustics alone can potentially produce false alerts resulting from innocuous loud noises. In these cases, external validation measures are needed to verify a gunshot before an alert is sent to authorities. Some systems send audio files to human analysts or stream audio to the cloud to confirm “possible” shot events. Audio clips sent outside of a local server, however, can raise privacy concerns. Additionally, sensors that rely on any type of external validation inherently slow down the notification process, weakening the benefit of real-time alerting.

Navigating the Landscape of Gunshot Detection Systems

More than 20 years of realistic active shooter drills being conducted in schools and other environments have shown that these drills are potentially more traumatizing than they are beneficial. Gunshot detection systems that have simulation and training modes can activate shot detection in the software without needing to present a weapon into the environment. Like fire alarm drills, a simulated active shooter drill can help organizations initiate a calmer, more organized, less traumatic training experience.

School safety administrators need to understand the uses of multiple technologies and how they can be effectively deployed without breaking the budget. Manufacturers that cannot clearly describe how their technology works, that rely on downplaying competitor products, or that do not embrace the added work of third-party verification are only creating more confusion about what solutions will deliver the best results.

For all the benefits that gunshot detection can bring to an organization, one of the difficulties with system selection is that there is no central governing body that regulates the industry or monitors marketing claims. Until that day comes, one important resource that schools should use is the U.S. Department of Homeland Security (DHS) SAFETY Act program. Technologies that are SAFETY Act certified bear the agency’s red seal of approval. This indicates that the solution is listed on the DHS Approved Products List for Homeland Security and has been vetted by the DHS Science and Technology Directorate.

Schools can look to experts like security consultants or integrators to advise them on system selection, implementation and integration, as well as funding vehicles. If a school does not have a relationship with a trusted security consultant or integrator, administrators should seek out security systems providers that specialize in video, access control and emergency notification systems. In addition to national solutions providers, there is a growing number of smaller, regional systems integrators who offer an indoor gunshot detection product.

By employing gunshot detection systems, schools can add a crucial layer to their existing security and crisis response plans that is purpose-built for fast response and mitigation of loss of life.