Residents from across Cambridge gathered Saturday morning to help shape the city’s approach to public safety in the first-ever civic assembly held in Massachusetts. Among the group was a woman approaching her 80th birthday who has lived in the same building in The Port for half a century, three Cambridge Rindge and Latin School students, a mental health clinician who moved from Chicago nearly two decades ago, a third-generation Cantabrigian living in West Cambridge a woman who values Cambridge’s walkability but feels unsafe when walking home late at night and a lifelong North Cambridge resident concerned about recent shootings in her neighborhood.
All are among the 40 residents selected by lottery to reflect Cambridge’s demographics, and had volunteered to participate (each will receive a $1,000 stipend for completing the four sessions). They will weigh the future of the city’s ShotSpotter gunshot detection system and surveillance cameras in public parks. And they may help heal a city riven by a death some think might have been prevented had the sound detection system not been deactivated by Cambridge’s City Council May 18.
“When this process is finished, I hope you have done more than just make recommendations about technology,” said the Rev. Dr. Jeremy Battle, senior pastor of The Avenue Fellowship and a member of the assembly’s advisory committee, which helps guide the process, review educational materials and ensure participants hear balanced perspectives. “I hope you will have strengthened the way the city of Cambridge listens to itself from this inaugural moment.”
The civic assembly was set in motion Aug. 3, when the council voted 6-3 to temporarily restore ShotSpotter and gather citizens to help determine its future.
The assembly will meet for seven hours a session over four Saturdays through Dec. 5, then present recommendations to the City Council. The council is not obligated to adopt them. The first session can be viewed here.
Crunching the numbers
They started with data. Cambridge Police Department crime analysts Meghan LaMonica and Rebecca Leonard reviewed local crime trends showing the city recorded 475 violent crimes in 2025, less than half its 1990 peak of 1,077, although serious crime has risen since reaching a 55-year low in 2019.
Gun violence remains concentrated in a handful of neighborhoods. Of 134 confirmed gunfire incidents citywide between January 2014 and Oct. 15, 2026, 68 occurred in The Port, and that neighborhood together with Cambridgeport and Wellington-Harrington, accounted for roughly 70% of incidents.
ShotSpotter covers approximately 1.25 square miles, or 18%, of Cambridge’s land area, encompassing much of those neighborhoods. Although that area accounted for 74% of confirmed shootings between July 2014 and May 2026, ShotSpotter detected only 58 of the 96 confirmed shootings within its coverage area, a rate of 60%.
Between 2015 and 2025, 35% of ShotSpotter alerts corresponded to confirmed shootings, compared with 18% of gunfire-related 911 calls. Following upgrades in 2021, ShotSpotter’s confirmation rate rose to 53% between 2022 and 2025.
“Just because an alert is unfounded, it does not definitively mean that a shooting did not occur,” Leonard said. “It just means there was no evidence located that there had been a shooting.”
The science of surveillance
Ermus St. Louis, an assistant professor at Northeastern University, presented research on surveillance technologies nationwide, urging participants to distinguish between technologies that help police respond to crimes and those that prevent them.
In Chicago, which discontinued ShotSpotter in September 2024, a 2021 inspector general investigation found that just 9.1% of police responses to more than 50,000 alerts produced documented evidence of a gun-related crime. A separate 2024 study found that ShotSpotter increased firearm recoveries by roughly 11% but did not significantly reduce shootings or other serious gun crimes.
A yearlong pilot in Durham, N.C., reduced median police response times by 1.2 minutes, but the system detected only 26 of 52 shootings involving injuries or deaths, compared with 50 reported through 911 calls. Researchers could not determine whether the technology reduced gun violence, and Durham declined to extend the program in March 2024.
Assembly members are also considering whether surveillance cameras should be in public parks. St. Louis pointed to programs in Philadelphia and Phoenix, noting that neither had demonstrated a reduction in crime. He urged participants to consider who would monitor Cambridge’s proposed cameras and how recordings would be stored and shared.
“These often try to solve relational problems with technology, right, and it’s just a quick fix,” St. Louis said. “It’s not going to address the underlying issues that’s causing problems.”
The case against ShotSpotter
Following lunch, Gideon Epstein, policy counsel for the ACLU of Massachusetts’ Technology for Liberty program and a Cambridge resident, made the day’s first full-throated case for discontinuing ShotSpotter, arguing that it threatens residents’ privacy and civil liberties.
Epstein cited a 2015 Massachusetts Superior Court case, Commonwealth v. Denison, in which ShotSpotter recorded a conversation surrounding a fatal shooting. A judge ruled that the recording violated the state’s wiretap law and suppressed the evidence.
He also criticized Cambridge’s limited oversight of ShotSpotter, which was installed before the city adopted a 2018 ordinance requiring City Council approval before deploying new surveillance technologies. ShotSpotter’s approximately $50,000 annual cost is covered through a federal Department of Homeland Security grant administered by Boston, which holds the contract with ShotSpotter’s parent company, SoundThinking. The company owns the collected data, while Cambridge licenses its use.
Epstein questioned how the data could be shared without direct local control, noting that the ACLU had yet to receive information it requested from the city nearly three months earlier.
“My ask to this assembly is that you recommend that the city council discontinue ShotSpotter deployment,” Epstein said. “And to the extent residents believe that we need this kind of audio monitoring or gunshot detection technology, let’s start from square one. Let’s follow what the surveillance technology ordinance calls for, which is a public hearing, impact assessments, and a vote from the city council before any deployment happens.”
The case for ShotSpotter
Assembly members also heard a defense of ShotSpotter from Cambridge Acting Police Commissioner Pauline Wells. She argues that while it cannot prevent shootings, it helps officers locate victims, provide emergency care and collect evidence. She urged participants to recommend keeping the system.
Wells emphasized that alerts do not automatically establish that a shooting occurred or make nearby residents suspects. She reported no civilian complaints or uses of force associated with ShotSpotter responses during its 12 years in Cambridge.
She cited a July 2024 shooting on Harvard Street in which she credited an early alert with saving a man’s life, a September 2022 alert that led police to recover a loaded handgun near the King Open School a few hours before students arrived, and an August 2022 alert that prompted a domestic violence investigation at Putnam Gardens, resulting in an arrest.
“ShotSpotter may not detect every shooting, but we’ve seen situations here in Cambridge where it has helped officers respond faster, [provide] life-saving care, and recover dangerous weapons,” Wells said. “Just because a tool doesn’t work 100% of the time doesn’t mean it isn’t valuable, especially when it has the potential to save someone’s life.”
Challenging Epstein’s privacy concerns, Wells said ShotSpotter’s sensors retain audio on a rolling 24-hour basis, overwriting it unless multiple sensors detect possible gunfire. Only short recordings associated with alerts are preserved. However, a recording she played of an actual Cambridge shooting included audible human voices, which she acknowledged while maintaining that the system was not designed to monitor conversations.
Wells also defended the federal funding arrangement, arguing that ShotSpotter’s lack of direct cost to Cambridge was a benefit.
Finding common ground
Following the presentations, participants broke into smaller groups before reconvening to share principles they believed should guide Cambridge’s use of surveillance technology. Several emphasized local control over surveillance data, transparency and regular evaluations of effectiveness. One group argued that Cambridge should control data collected within its borders, while another called for safeguards to track who accesses sensitive information. Others stressed that technology should complement, rather than replace, community relationships and efforts to address the causes of violence.
In a statement Monday, Mayor Sumbul Siddiqui, who attended the morning portion of the assembly, praised participants’ thoughtful questions and engagement.
“I also want them to know that their work matters,” Siddiqui said. “The City Council called for this assembly, and we have a responsibility to take their recommendations seriously and explain how they inform our decisions.”
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