Are Evolv’s smart weapon detectors smart enough?
In a nation stunned by mass shootings, demand for the Waltham company’s AI-powered scanners is soaring
Mike Ellenbogen likes to say that his company, Waltham-based Evolv Technology, makes weapons detectors, not metal detectors. That’s because Evolv systems are designed to detect guns, while ignoring other metallic items like car keys and smartphones.
But last October, an Evolv scanner at a Utica, N.Y., high school didn’t detect the knife that a student used to stab a classmate. The victim survived, but the Utica school system removed all its Evolv scanners, just months after signing a nearly $4 million contract with the company.
The Utica incident was a high-profile embarrassment for a company whose security gear screens visitors to leading sports venues, including Fenway Park and Gillette Stadium, as well as concert halls, museums, and schools throughout the United States. Evolv has come under scrutiny from major media outlets, including National Public Radio and the BBC, and a security industry watchdog organization has charged that Evolv sought to conceal the scanner’s limitations.
Ellenbogen, the company’s cofounder and chief innovation officer, acknowledges that the system has trouble identifying knives, but says it has proven successful at detecting guns and reducing the time spent in security lines. Each day, Evolv systems find 400 guns being taken into crowded places — rarely with criminal intent, Ellenbogen said.
“The system is very, very reliable,” Ellenbogen said, “at detecting what it’s designed to detect.”
Customers seem to agree. In a nation stunned by mass shootings at schools, shopping malls, and workplaces, demand for Evolv’s gear is soaring. Revenues jumped 136 percent last year to $55.2 million, and nearly 300 new customers signed up, compared to just 84 in 2021.
Evolv still isn’t profitable, but the publicly traded company predicts revenues will hit $60 million to $65 million in 2023 and that it will reach profitability in 2025. The company’s stock, traded on the Nasdaq exchange, has more than doubled in value in the past year to about $6 a share.
The Evolv Express detector works on
much the same principle as traditional metal detectors. It generates a magnetic field that is disturbed by the presence of metallic objects. But Evolv adds artificial intelligence software to recognize the specific patterns of distortion caused by different objects. A gun will affect the magnetic field differently than a phone.
By training the software on thousands of different weapons and objects, Evolv claims to have created a smart metal detector that can distinguish between objects, and sound an alarm only when there’s a real threat.
In addition, the Evolv Express aims a video camera at each scanned person. If someone is carrying a suspicious object, an alarm sounds and a video screen displays the person’s image with a red box superimposed on the location of the object. Security personnel can instantly see if the object is in a pants pocket or strapped to an ankle.
The goal is a device that processes people much faster than traditional models, which can be set off by any small metal item. Evolv Express was created for venues that must handle thousands of visitors quickly. So it’s programmed to ignore items that are probably not a threat. Even if visitors are carrying keys or a phone, they should just pass through and keep going.
“This’ll do 4,000 people an hour with very low false alarm rates,” said Ellenbogen.
Eric Neill, director of theater operations at the 3,500-seat Boch Center in Boston, said the Evolv system has made the lines outside his theater much shorter. “People are getting in and getting in quick,” said Neill.
“The system itself was everything it was advertised.”
Brian Schultz, chief operations officer of the Charlotte Mecklenberg school system in North Carolina, saw Evolv Express in action at a Carolina Panthers football game and decided it was just what the schools needed.
In 2021 “we had a proliferation of guns on campus,” Schultz said. “Metal detectors were not a useful tool in our schools because of the number of students we have.”
Since the Evolv system was installed in 2022, only seven guns were confiscated during the school year, compared to 31 the year before. Schultz believes the presence of the Evolv system, along with peer pressure, deterred students from showing up with firearms.
But Schultz noted that some knives slipped through the net, and were only confiscated because of tips from students. Schultz said he wasn’t surprised; Evolv told him upfront that the system would not always detect knives.
But IPVM, an organization that conducts research on the security industry, accuses Evolv of deliberately concealing the system’s weaknesses.
“They go to great lengths to make sure the people don’t understand what the system can or can’t do,” said Donald Maye, IPVM’s head of operations.
Evolv asked the National Center for Spectator Sports Safety and Security at the University of Southern Mississippi to test the performance of its system. The resulting 52-page report found that the system frequently failed to recognize knives, but a shorter version of the report released to the public left out this crucial detail, Maye found.
Maye uncovered the additional information by filing a public records request with the University of Mississippi, which is a state school.
Ellenbogen admits that Evolv got the university to strip out details from the public report, but only to avoid revealing details that might help criminals defeat the system. “We treat that as security-sensitive information,” said Ellenbogen. “The security professionals need to know that, and we’re very transparent with them about exactly what the system does and doesn’t do. The general public doesn’t need to know.”
Even if Evolv works as advertised, said David Riedman, founder of the K-12 School Shooting Database, any type of metal detector is unsuitable for schools.
“Seventy percent of shootings on school property happen outside the building,” said Riedman, whose organization tracks school shootings in the United States. In such cases, a weapon detector at the front door is useless.
Besides, metal detectors require multiple well-trained workers. Every airport checkpoint has people who check IDs, operate body scanners, and conduct bag inspections, as well as workers who pat down some passengers, and still others who ensure other entrances are secure. Few public schools could afford all these workers, but without them, Riedman said, metal detectors can be easily bypassed by a determined shooter.
And then there’s the cost. A traditional metal detector costs around $10,000. But Evolv offers its product as part of a service package that costs around $2,500 a month per scanner and is generally offered under a fouryear contract. That’s $120,000 over four years to cover just one door.
The Charlotte school system, for instance, is paying $15 million to install Evolv in all its schools.
But more schools are willing to pay the price. Eleven of the nation’s 100 largest public school systems now use Evolv. In March, the company said it had scanners in 450 US school buildings, compared to 200 six months earlier.
Ellenbogen vows that the Evolv system will keep getting better. The company recently released a software update to improve knife detection. The goal, said Ellenbogen, is a system that always gets it right.
“I don’t know if it’s a possibility,” he said, “but it’s something that we literally work on every single day.”