Tuesday, August 30, 2022

Acoustic Gunshot Detection Tech - the good, the bad, & the ugly

by Mateja Mihinjac

I’ve recently come across a report titled “ShotSpotter and the Misfires of Gunshot Detection Technology” by the STOP Surveillance Technology Project.

The report is extremely critical of this Acoustic Gunshot Detection Technology (AGDT) suggesting it offers little operational value for the police and it can prove detrimental with serious ethical caveats.

How bad is this technology really? 


ShotSpotter Inc. has been on the market for 20 years and it is the leading AGDT on the market used by over 200 police jurisdictions worldwide, with at least 130 of those from the US. 

ShotSpotter prides itself with the slogan: “Right place, right time. Precision policing solutions that help save lives, solve cases and deter crime – making communities safer.”

AGDT technology starts with microphones mounted above
the city on buildings and other tall structures

ShotSpotter combines narrow AI with human experts to identify and locate gunshot events and their location in the neighbourhoods where it’s been installed. Its detection system comprises microphones placed on streetlights, buildings and utility poles, and audio software that compares the sounds with prior gunshot events in its database. The system triangulates the location of the sound that is further reviewed by a human sound analyst who alerts the police should they determine the sound actually derives from a gunshot. 


Company reports, and some technology reviews, offer that it detects shootings that would go unreported, locates gunshots for quick police response, and improves the arrest rates of suspects. This all leads to preventing gun violence and enhanced neighbourhood safety.


The evidence suggests that many of the above claims can be disputed. For example, while quasi-experimental studies indicated over 80% accuracy in detection and triangulation, other studies show the AGDT works poorly in detecting gunshots and, instead, it suffers from what researchers call “false positives” (it gets it wrong). 

Chicago’s Office of Inspector General review found that only 9.1% of probable gunshot alerts out of 50,000 records over a 17-month period resulted in evidence of a gun-related offence.

While we sleep at night, it listens for gunshots from roof-mounted
listening devices - what could go wrong?

These studies conclude that AGDT may actually be ineffective and inaccurate and can thus waste police resources. None of that mentions the cost, (Chicago paid $33 million for 2 years of service).

As well, there are poor outcomes on firearm offence reduction and shooting victims’ medical outcomes two years following the installation. Thus, it did not lead to gun violence deterrence as anticipated.

Most alarming was whether ShotSpotter evidence should be used in court. The company has previously admitted to altering the records and reclassifying the sounds that were initially not detected and determined as gunshots but were later reclassified as such based on police reports. While this may be occasionally warranted, at other times it may lead to the misuse of data and misrepresentation of the evidence on the side of the law enforcement agencies.  


AGDT can lead the local community to become disengaged and stop reporting gunshots because they believe the technology will handle that for them. In St Louis, for example, citizen-initiated reports of gunshots before the installation of ShotSpotter were 7 times more useful than AGDT and wasted less police time. Following the installation, citizen reports significantly decreased and decreased further when the system was expanded.  

AGDT is predominantly deployed in poorer and majority Black and Latinx neighbourhoods commonly identified as hotspots for shootings and violence. While there might be more shooting incidents in those neighbourhoods, this automatically means AGDT will detect more shooting incidents in those specific neighbourhoods rather than in other neighbourhoods where it is not deployed. This might perpetuate the problem of over-policing and racial bias in communities of colour. 

Evaluations of AGDT shows problems with "false positives"
- it turns out the city can be a noisy place

There is a similar problem with another narrow AI program called predictive policing where there are reports of racial discrimination and over-policing and the additional concern of “tech washing”.

Despite ShotSpotter’s claim that the sensors cannot record private conversations, there are increasing concerns of the microphones recording regular conversations and acting as a “massive eavesdropping device”.

In one case, such a private conversation in a public space was intercepted and admitted into evidence in a murder trial court case.

Currently, there appear to be no regulations that would prevent ShotSpotter from sharing stored audio recordings.

SafeGrowth works directly with community residents in collaboration with the police to plan their own safety strategies


After two decades, the results of AGDT implementation continue to show few positive effects. In fact, some results are detrimental to effective police work, police-community relationships and community safety.

The evidence suggests that police leaders should err on the side of caution and turn towards approaches for addressing gun-related violence that have a better track record.

One example: combining neighbourhood policing and problem-oriented policing to build police-community relationships, act proactively, and approach the problem at its core. 

Another that we obviously recommend is SafeGrowth. This blueprint for neighbourhood safety planning helps residents help themselves, in partnership with police and using the latest in crime prevention. SafeGrowth provides a platform to help address gun-related violence and other crime and safety problems. 

The documented success story in the New Orlean’s gun-violent neighbourhood of Hollygrove is only one example of how neighbours disrupted gun violence. 

Sometimes the most effective solutions are not technology, they are human-based and neighbourhood friendly. That, we believe, is a future we all want. 

Saturday, August 20, 2022

Reducing Zone 2 crime - The power of art co-ops

Denver Art Society Co-op in the heart of Denver's Santa Fe arts district
- photo Denver Art Society

by Gregory Saville

In last week’s blog, Tarah discussed the crime theory called concentric zones, that she lives in what feels like a Zone 2 city (Hamilton, Canada),  and how that theory predicts why crime clusters in Zone 2 areas around the central city. 

The question is what can be done about it. Some believe a Zone 2 high crime neighborhood will always be a high crime neighborhood. Experienced practitioners in crime prevention and community development know that is nonsense.

First, we know that carefully planned redevelopment can transform a high-crime neighborhood back from the brink. The CDC movement (community development corporations) is the lighthouse for redevelopment, such as the work of Philadelphia’s HACE organization and the work of the redevelopment corporation, LISC. The book Comeback Cities shows us how that is done.

True, that usually involves multi-year investments, big money, and long-term development. But there are other ways. 

Art murals appearing near Denver Art Society


What does an art gallery have to do with creating livable places and cutting crime? Why should people looking to create safe places really care about an art gallery? If that gallery is part of the co-operative movement, it is worth a closer look.

When the urban writer Jane Jacobs wrote about safe places in her landmark book “The Death and Life of Great American Cities” she was, above all, talking about the social life of streets and how, exactly, those streets actually work. She wrote: 

“It may be that we have become so feckless as a people that we no longer care how things do work, but only what kind of quick, easy outer impression they give.”

If you look carefully at how co-operatives work, you will see why we should care and support them.

Denver city has now begun expanded streetscaping for better walkability


Today co-ops are everywhere. The Denver Art Society (DAS) is such a co-op. A dozen years old, it comprises over 100 artists and musicians who teach, perform and sell their own art in the arts district of Denver. DAS is the epicenter of the Denver Santa Fe arts district with music shows, art displays, and classes. After a decade of operation, it has spurred the creation of other interesting businesses and street artifacts. For example, the city has begun streetscaping Santa Fe and local murals and cultural centers line the street. 

Like most co-ops, DAS is run by volunteer members who conduct community outreach to the neighborhood and also to local schools. They teach inexpensive art and music classes for burgeoning creatives. They have helped the homeless find a roof or a place of refuge. They beautify alleyways with mural painting events. When you understand how they actually work, art gallery coops are not a quick fix. They take time and can be complicated, often convoluted, undertakings. But, work they do. 

The band MOOSGH, based at DAS, chilling out back on Mural Painting Day 

I admit a personal bias toward the Denver Art Society since my band MOOSGH was born there, and our studio is based at DAS. It’s true there is still some theft, nearby homelessness, and other problems. But there is no doubt, from what the DAS founders describe, that this neighborhood is a far better place today than a decade ago. Police crime stats show the DAS neighborhood has a crime rate four times less than the nearby CBD or the adjacent Capitol Hill neighborhood. 

As Jacobs taught us many years ago, when people love a place, they end up looking after it. Co-ops help nurture that process.

Nearby cultural center across from DAS. Cultural activities can
transform Zone 2 neighborhoods


I have witnessed the co-op open gallery idea transform other Zone 2 neighborhoods in other cities. Co-ops are an idea that – when you know the mechanics of how a place actually works – would lead you to conclude that all self-respecting urban planners, urban politicians, and crime prevention practitioners must study, learn, and adopt in their plans. 

The co-operative movement began with Welshman Robert Own in the 1800s, a wealthy cotton manufacturer who believed in creating livable communities for his workers. He helped them create a co-operative store so workers could lift themselves out of poverty by growing their own food, making and selling their own clothes, and otherwise working together to better their lives. 

It’s time city planners, decision-makers and criminologists paid more attention to the co-op movement.

Friday, August 12, 2022

Living in zone 2 - a Steel City in transition

On the street in Hamilton, Ontario

by Tarah Hodgkinson  

When we came back to Canada, we wanted to live somewhere affordable and close to work. But we also wanted to live in a city. I love city life. The different cultures of each neighbourhood, the density, the people, and the food options!

So, we chose Hamilton. It met all of our criteria. And importantly, the people felt real. I had lived in beautiful, but gentrified, cities like Vancouver and Brisbane. They were clean, beautiful, and had great amenities, but also expensive and exclusive.

Hamilton felt different. There were people from all walks of life here. It felt genuine. But Hamilton is also a city in transition. When we think about areas in transition, many criminologists or sociologists will be reminded of crime theories of social disorganization and concentric zones.


In the early 1900s, criminologists Robert Park and Ernest Burgess outlined 5 concentric zones that made up city life in Chicago. These went from a zone surrounding the central business district (zone 1) all the way to the commuter zone in the wealthy suburbs (zone 5). Some zones, they said, were more vulnerable to crime.

Zone 2 neighbourhoods are in transition

Zone 2 was the zone in transition. This zone surrounded the central business district, and usually housed new immigrants or the poor as they could not afford to live anywhere but right beside the factories. When they made enough money, they would transition out of the area. This meant that there was very little cohesion and informal control in this zone, and as a result, this zone had the most crime.

Looking around Hamilton, the entire city feels like zone 2. Now, of course, there are areas that are beautiful and thriving. But having spoken to people working across the city, we’ve learned that Hamilton has fallen on hard times. COVID hit hard. People lost jobs and businesses. Poverty and homelessness are obvious and rampant. Mental health issues are evident everywhere. People here are struggling.

Hamilton feels like a Zone 2 city

Hamilton, like many of its struggling working-class city counterparts, is a manufacturing city.  The waterfront is lined with factories and 60% of the manufacturing is steel. But major employers like Stelco, have gone belly-up. And like Detroit and other manufacturing communities, Hamilton was hit hard by these major job losses.


But there are also signs of change. Hamilton has been labeled Toronto’s “Brooklyn,” as many Torontonians are leaving the big city for more affordable housing (though it is still inaccessible to most people in the city) and funky and alternative places that support local art, food, and people (see Ottawa Street).

If there is one thing we’ve learned from places like Brooklyn though, the people of Hamilton are going to have to be careful to maintain an affordable and connected community. While it might seem easier to wait for external money to make Hamilton a suburb of Toronto, doing so would spell trouble for the people who live here now. Housing needs to stay affordable. Social services need to be improved for those who are struggling. 

As we have learned from working with folks from zones in transition around the world, one of the first steps down that path is by empowering neighbourhoods through methodologies like SafeGrowth. Like other zones in transition, Hamilton residents will need to take action to not only improve their community but also keep the things that make it great.  We can’t wait to see what happens next.