Precision Law Enforcement: Can Gunfire Detection Technology Serve and Protect Everyone?

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[00:00:00] Joe Selvaggi: This is Hubwonk. I’m Joe Selvaggi. Welcome to Hubwonk, a podcast of Pioneer Institute, a think tank in Boston. Memorial Day marks the start of summer and an attending rise in gun related crime, particularly affecting marginalized communities in cities nationwide, including Boston. One tool that has emerged to help law enforcement address gunfire is ShotSpotter, a network of sensors placed in high crime areas.

[00:00:28] These sensors enable police to triangulate the sounds of gunshots and respond swiftly. Before ShotSpotter’s deployment, about 80 percent of urban gunfire incidents went unreported, hindering criminal investigations and timely aid to victims. However, critics of sound thinking, the company behind ShotSpotter, are concerned that the technology could lead to over policing in vulnerable communities.

[00:00:53] U. S. Senator from Massachusetts Ed Markey has requested the Department of Homeland Security investigate the use of ShotSpotter for potential violations of the 1964 Civil Rights Act. And the American Civil Liberties Union has filed a lawsuit against Sound Thinking, alleging that the technology disproportionately targets communities of color and results in unfair policing.

[00:01:15] How does ShotSpotter work? How is it deployed? And how well can it address public concerns for its accuracy and precision to allay fears that its use unfairly targets vulnerable communities for illegal searches or arrests? My guest today is Tom Chittum, Senior Vice President of Forensics at Sound Thinking and former Associate Deputy Director of the Bureau of Alcohol, Tobacco, Firearms, and Explosives.

[00:01:39] Mr. Chittum, an attorney with over 27 years of law enforcement experience, has conducted and overseen thousands of investigations and frequently testified as an expert witness. He will discuss the capabilities and limitations of ShotSpotter technology, the criteria used to select sensor deployment locations and how ShotSpotter enhances police department’s ability to respond to gun crime. He will also address the concerns for civil rights and liberties of his critics by describing how the tools are a complement and not a substitute for high quality law enforcement practices. When I return, I’ll be joined by Senior Vice President of Sound Thinking, Tom Chittum.

[00:02:17] Okay, we’re back. This is Hubwonk. I’m Joe Selvaggi, and I’m now pleased to be joined by Sound Thinking’s Senior Vice President of Forensics, Tom Chittum. Welcome to Hubwonk, Tom. I appreciate you having me. Great. Well, I’m thrilled to have you on the show. your firm’s technology has been in our news recently when our, our junior senator from Massachusetts, Senator Ed Markey, wrote a letter, recently wrote a letter to Homeland Security, asking for an investigation into grant funding for your Shot Spotter technology.

[00:02:44] Your firm’s name is, Sound Thinking, but the technology’s shot spotter. the concerns, Senator Markey had were that your technology as it’s deployed. May run afoul of Title VI of the Civil Rights Act of 1964. I’ll just state for our listeners who don’t know that, particular Civil Rights Act, it’s, “no person in the United States shall on the ground of race, color, or national origin be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any program or activity receiving federal financial assistance.”

[00:03:15] So his letter was also signed by another of our senators, Senator Elizabeth Warren and our representative Ayanna Pressley. So, for that reason, I wanted to have you on the show to talk about the technology, how it’s designed, how it’s deployed. And, frankly, with our listeners discuss the promise and pitfalls of the technology so they can form their own decisions.

[00:03:33] So, as our listeners know, I like to start at the beginning in a very basic level, with, a brief description of what ShotSpotter technology is, and what does it do? So, let’s start there.

[00:03:44] Tom Chittum: Sure. Well, if you had asked me before I knew how ShotSpotter worked, I would have had to guess that it was powered by magic, because how could it possibly do what it claims to do?

[00:03:58] But I know now that it is not magic at all. In fact, its basic math, science, and technology that’s been harnessed for public safety good. And the company has an interesting background, and I think we may talk about that, but at a base level, our system uses sensors that are spread out over a large area, they detect loud impulsive sounds like gunfire, and then we go through a process of calculating the time difference of arrival, the time that, that, sound reaches each of our sensors, we calculate the difference, and by doing that, we can determine where the sound came from.

[00:04:35] We also use some processes to sort out things that are not gunfire, so that what’s left behind is gunfire. We publish those to our customers, mostly the police, so they can respond quickly and precisely to where gunfire occurs. It does all of that in less than 60 seconds, and that matters because when you’re talking about gunshots in urban areas, very often time is of the essence.You’re dealing with gunshot wound victims, you’re dealing with ephemeral evidence. And so, police agencies all across the country use Shot Spotter as one tool along with other tools to help address gun violence.

[00:05:13] Joe Selvaggi: So that to me, sure, may sound like magic, but that may align, aligns with my own view of, let’s say, a GPS, how my phone knows where I am based on how my signal might bounce off of towers or satellites.

[00:05:24] So I think it’s, you’re doing very similar technology, with sound. Now I read it in some of the background that there may be as many as 34 individual patents in your technology. How did all of this technology begin? What are the origins of Shot Spotter?

[00:05:38] Tom Chittum: Well, it’s a great story. Dr. Bob Schoen, Dr. Bob, he still works for the company today, and he’s a great gentleman, in the mid-90s, could hear gunfire near his house. In California, it occurred to him that he might be able to use the same processes that earthquake scientists use to locate the epicenter of earthquakes. He might be able to use that to locate where the sound of the gunfire was coming from.

[00:06:04] And so he built a prototype, and he tested it and it worked. And that’s how Shot Spotter was born. Our headquarters is still in California, but as I mentioned, we’ve spread all across the country and now the globe. We’ve got international customers, too. More than 170, customers, rely on Shot Spotter to help them know where shootings occur, but it all started, from the idea that one man had. In his home in California, I had a recent occasion to sit down and talk with him, and he said during, some of the early tests, to see whether or not it could detect sounds, he had set up sensors on his house and some of his neighbors houses, and he would go outside and pop balloons to see if the sound would trigger it.

[00:06:49] The system now, of course, this is an early prototype. So don’t let that mislead you into thinking that the system is set off by balloons. But what he was doing was testing whether or not he could locate precisely where the sound was originating from. and he did. We do have a lot of patents. I said that it’s a simple system and it is, it’s very sophisticated in the way that it works, the data that we use to power it, but at base level it really relies on well-known and fairly simple scientific concepts.

[00:07:22] Joe Selvaggi: So, you mentioned briefly that it’s deployed, I think you said 170 different clients across the country and also internationally. Just briefly, name some of the big cities that are using it. I’m going to include Boston in there, but also maybe if there are other Massachusetts cities that have also used the technology.

[00:07:40] Tom Chittum: So, we’re deployed in major cities across the country. Presently, we’re still deployed in Chicago. We’re deployed in New York City. We’re deployed in Boston, but we’re also deployed in very small cities, too, and medium sized cities. And sometimes people think that ShotSpotter is only a tool for very large metropolitan areas, but the reality is gun violence affects communities in a lot of places in a lot of ways. And so, really in some places, even our smaller customers, end up being some of the best users because they have a manageable problem. They can respond effectively. And so, we’ve really seen it put to good use in a lot of places across the country.

[00:08:23] Joe Selvaggi: So, let’s focus on Boston again. I know you’re in DC now but I’m in Boston and it’s a big city, with lots of different neighborhoods. I want our listeners to understand when a city like Boston, which has a common police department, maybe lots of precincts, ahead of police, when they call you and say, we need your help. How do you decide where to put these sensors, these, this technology that’s listening for shots. You can’t put them everywhere. It’s a big city. Where do you, what happens next when you say, okay, let us help? Where do you decide to put the sensors?

[00:08:51] Tom Chittum: Well, we decide where to put the sensors, but we don’t necessarily decide where to put the coverage areas. So, when a customer approaches us, obviously it’s because they want to address the gun crime issues that they have. Look at objective historical data, things like reports of homicide, prior reports of gunfire, to try and determine those areas where the tool can do the greatest good. I wish ShotSpotter was deployed everywhere. There is a diminishing return on your investment if you’re deploying it in places where there is no gunfire. You pay for a service that doesn’t get used very often. Even still, there are some value in putting it in places like that where it serves as an early warning system for when incidents occur. For instance, we’re deployed on college campuses across the university where these low frequency high consequence events like school shootings may occur and where, timely intelligence is of the essence but, with respect to, police, departments and communities, we look at their, historical crime data. Where is it that they experience the most gunfire? Where have most people been killed by gunfire? And then it’s ultimately up to the customer to decide where the system should be deployed.

[00:10:17] Once that’s determined, the company itself deploys the sensors, and we keep those locations secret for a few reasons. So, we go out, we install them ourselves, we maintain them ourselves. But ultimately, it’s the customer who decides what area gets covered.

[00:10:34] Joe Selvaggi: Now, you already mentioned that it’s a very advanced technology, but it’s using sound. Cities are a noisy place. I know, I live in cities, always have, how precise can the, the sensors triangulate on where a particular gunshot is occurring. There’s echoes and all kinds of confounding noises. How precise? Are we talking about a neighborhood wide, block wide, or can you zero in on a precise location of where a shot was heard?

[00:11:02] Tom Chittum: Yeah, so, well, first, when you talk about the science behind it, you mentioned earlier that we have several patents. We post them on our website. We’ve also written academic papers explaining exactly what it is we’re doing. Some of them are quite dense for a layperson like me. I have to read them slowly to understand them.

[00:11:23] But we explain the science. It’s not secretive what it is that we are doing. And our system, uses several layers of filtering to make sure that the sounds that we are publishing to our customers are, in fact, gunfire. So, the first way is just by the nature of the way the sensors are deployed. They’re spread out over a large area. It’s not really a filter, but you might think of that as spatial filtering, because our system is only triggered when three or more sensors detect a loud impulsive sound. So, if you went outside, and slammed your car door, it might make an impulsive sound, but it’s not going to reach three sensors spread out over that area.

[00:12:03] If you went out and screamed at the top of your lungs, that sound might be able to reach three or more sensors, but it’s not an impulsive sound. And so, our system is only triggered when three or more sensors detect a loud, impulsive sound, like a bang, a boom, or a pop. And then the system goes through a process of locating where that sound originated from to your question, we are quite precise. Our system locates to a precise latitude and longitude. To account for things like, the diffraction around buildings, we set our margin of error at 25 meters. So, for frame of reference, that’s about how far an adult can throw a baseball. So, if you stood in the middle of a circle and threw a baseball, in that circle is where we guarantee, the gunfire has originated from.

[00:12:52] And we do give guarantees to our customers. Our guarantee is 90%. No system that operates in the dynamic real world, as ours does, could ever be 100%, but we do set a high standard. We carefully track metrics. We report those to our customers. We report them to all of our customers, and we give them a financial incentive to provide us feedback.

[00:13:15] If we make mistakes and don’t meet the 90 percent threshold, guarantee that we give them. They pay us less. And so, they’re encouraged to provide us feedback. Let us know when we make mistakes so we can use that information to make the performance of the system better and measuring that performance across all of our customers over many years.

[00:13:35] We know that we keep an accuracy rate of about 97 percent, and so that’s pretty good. occasionally the system, will miss a shooting that actually occurs. There can be reasons for that. Our system has limitations. It’s only designed to detect outdoor gunfire. So, gunfire that occurred in an enclosure like in a home or a car may not be loud enough to reach our sensors or gunfire that occurred with a silenced firearm, a silencer, might not produce a loud enough report to reach our sensors. But to your question, it’s very accurate and it’s very fast and those things matter and matter, from academic research it pays big dividends for the police. They use the system and the communities that benefit from it.

[00:14:23] Joe Selvaggi: So, I want to unpack all the things you just mentioned. I just want to make a fine point on the precision. You say, you locate it, but you also mentioned there’s all kinds of things you don’t detect or detect but you don’t identify as gunfire. I’ve heard it alleged that things like firework and let’s face it a firecracker is an explosion like a rifle round or a gunshot or slamming car doors or as you say I’m not so much concerned about someone yelling but there’s all kinds of things that sound gun like. Would you consider let’s say a balloon popping or a garage door slamming or a firework going off? If you identify that would be considered an error, right? If you arrived and you saw fireworks, that would be scored as, we thought it was gunfire, it was a noise, but it wasn’t a gun. Would that be a mistake, or would that just be par for the course?

[00:15:14] Tom Chittum: So, let me clarify how that works. If we published it to the police and said, this was gunfire, but it was not. That would be a mistake. That our system detects it is not a mistake. Our system detects loud, impulsive sounds. But then we go through a process of filtering. So, I mentioned the spatial filtering.

[00:15:33] The point of that is just that the sense system covers a wide area. And so only, impulsive sounds of a sufficiently loud character will trigger the system to even detect and locate where it occurred. Once it does that, we use a patented process for filtering out sounds that are not characteristic of gunfire. Again, that patent is right there on our, website. It’s a public record. Anyone who wants to look at how we’re doing this, The system is very good at filtering out sounds that are not likely gunfire, but everything that has characteristics of gunfire then goes through a human review process where they do additional filtering to remove sounds that are not gunfire, and only after those trained reviewers determine that the sound is, in fact, gunfire, does it get published.

[00:16:26] And so there’s a number of levels of review. And there’s a big misunderstanding about what it is that our reviewers and our system is doing. Some people think that they only use their ears, that they just listen to a sound and try and guess whether it’s a firework or a firearm, but that’s not it. they also use their ears. They’re listening for clues. That it might be gunfire. Things like the cadence of gunfire, consistent, steady, strengths of the pulses that don’t overlap. They’re also using their ears to listen for audio clues that it is not gunfire. The whistling, sizzling. The popping of firecrackers, the inconsistent pulse strength, or overlapping pulses from a lot of firecrackers being lit.

[00:17:11] But they’re also looking at things like situational factors. If it’s 3 a.m. in a residential area, it’s not likely road construction. They are looking at sensor participation. Because our sensors are spread out over an area, we can determine the shape of the fire. of the propagation of the sound. And sound propagates omnidirectional, which is just a fancy way of saying it spreads out in all directions at the same speed. Think of it like a bubble expanding. But the way gunfire is made tends to be very directional. And so, our reviewers will assess the shape of the sensor participation. Is it linear, conical, versus encircling the sound? They’ll also look for things like distance to the nearest sensor. It reports that sort of information too. The sound of gunfire will travel further. And there are a number of other factors that they’re looking at too, so when people are told it just hears loud sounds and publishes them, that’s just evidence that either they want to mislead someone about how our system works or they simply don’t understand it.

[00:18:15] Joe Selvaggi: So, these, trained listeners, who could have many ways to analyze the sound, that you just outlined, are they your employees or are they people you train, for the benefit of the city so they can use your technology better?

[00:18:26] Tom Chittum: They are our employees. So, we maintain an incident review center. It is operational 24 -7, 365, and has been for more than 12 years, and they review every alert before it gets published for our customers. Because we are controlling those processes, we can maintain very strict metrics on their performance and keep a high and consistent standard across all of our customers.

[00:18:55] Joe Selvaggi: Maybe this is a sort of a too deep question or too leading of a question, but how does the accuracy translate into identifying gun related crime? Meaning, do you measure your accuracy against just gunshots, which I can’t imagine good benevolent reasons for gunshots going off in the middle of the city. But how well does that translate into gun related crime? Meaning, you don’t know whether the gun is being shot for fun or, bank robbery. How, how does that translate into, law enforcement, police? The effectiveness of the cops catching actual criminals doing crimes?

[00:19:32] Tom Chittum: Well, that’s a great question, Joe. So, when we publish an alert of gunfire, for us, it goes into the ether. We don’t know if it is celebratory gunfire or homicidal gunfire.

[00:19:49] I like to tell people that we can alert police to the what, the when, and the where of gunfire, but not the who. That requires them to respond and investigate. They provide us, feedback when the incident involved an officer, and so we have records of those. But most of the time, we don’t know what was on the other side, and so it really is up to the police to track those metrics, how often are they recovering evidence? How often are they locating gunshot wound victims? How often are they making arrests? There are a number of different metrics. They’re not all created equal. And what we see is there are a lot of factors that influence those rates too. What are the best practices that the department employs?

[00:20:34] How quickly are they responding? How much time are they spending on the scene when they get there? And so, from our perspective, that 97 percent really does depend on our customers letting us know when we make mistakes. It happens sometimes, not much. Occasionally, a shooting will occur and for whatever reason, our system won’t detect it. And our customers will say, hey, we have this gunshot wound victim. You missed it. What happened? And we’ll look at it and try and assess why that happened and that’s how our system performs. But again, measuring across 170 ish customers over many years and literally millions of incidents, we know that we keep a very high accuracy rate, in the high 90s.

[00:21:22] Joe Selvaggi: Well, that’s great. And the answer to your question brought to me one of the questions I wanted to ask perhaps earlier, but I noted at the top of the show that your title is Senior Vice President of Forensics. And some of your answers suggest forensic analysis, looking at what happened, taking apart the sounds and saying what really went on here. Does your title as Senior Vice President of Forensics suggest your expertise is used in a court of law, either for criminal or civil trials?

[00:21:48] Tom Chittum: Yeah. So, I am an attorney. I’m a licensed attorney. I have been for many years, but I didn’t always work as an attorney. Before I came to work for Sound Thinking, what was Shot Spotter when I joined it, I actually worked for the Bureau of Alcohol, Tobacco, Farms, Explosives, the ATF. I was an ATF agent for almost all of my adult life. I started out as a plain old agent in the streets working cases, but I worked my way up to the top. Through the ranks and when I retired in 22, I was the deputy director of the agency. I was the chief operating officer and that gave me a lot of opportunity to travel across the country talking to law enforcement leaders, elected officials, the public, the media.

[00:22:30] About how law enforcement can use the tools, the tactics, the technology of crime gun intelligence to do a better job of investigating gun crime. Because of that, I knew about Shot Spotter. At the time, though, it wasn’t so obvious to me the role it would play in the courtroom. Prior to coming to this company, I had only read one book. Court case about Shot Spotter. It involved the attempted murder of an ATF agent in Chicago. This agent was shot in the head. He survived. I believe he is indestructible. But Shot Spotter evidence was used in his trial to convict the gang member that shot him. Now that I’m here, though, I realize that Shot Spotter very often ends up in court.

[00:23:16] And so to your question, my role here is helping make sure that the evidence that our system produces is used effectively in court. And I make that point, without specifying prosecution or defense. Occasionally people We’ll assume that because we have contractual relationships largely with police agencies, we have some sort of pro law enforcement, pro prosecution bias, but that’s just not true. Our evidence is our evidence, and it is sometimes used by defense effectively in court too. That’s up to the attorneys to argue about what the evidence means. It’s our place just to say what the evidence is. And so, I oversee a team of professionals who appear in court and testify about what Shot Spotter detected. They’ve testified in over 300 cases in 24 states, and despite what some would lead you to believe, courts overwhelmingly acknowledge shot spotter as an appropriate and a unique factor in assessing things like reasonable suspicion of criminal activity, and they’ll also admit Shot Spotter evidence for its scientific value as well.

[00:24:31] Joe Selvaggi: So, let’s test your, bona fides as an honest broker here. If you, we’ve been talking about all the virtues of the technology, where might it be vulnerable to misuse? if it’s capabilities, but also its limitations and you testify on behalf of both, what would you say would, what are the limits? What can’t it do? What, where are its blind spots, if you will, or deaf spots, I suppose would be a better analogy. What, share with our listeners where it might be vulnerable.

[00:24:58] Tom Chittum: Well, so, I mentioned before that we can tell you the what, the when, and the where, not the who. Sometimes we can tell you the how, and I can give you an example of that. So, once we alert police to a shooting incident, it is really up to them to decide what to do. To use it effectively, one of the criticisms that sometimes people will make is that somehow Shot Spotter violates civil rights, and they’re often talking about this idea of stop and frisk policing. Shot Spotter says gunfire occurred here.

[00:25:32] Then it’s up to the police to go there and investigate. And when they do, they have to develop their independent, reasonable suspicion of criminal activity if they’re going to detain someone. This is America. You are free to go about your business without interference from police. But the Supreme Court has said that if police have reasonable suspicion to believe that you’re engaged in criminal activity, they can temporarily detain you while they investigate.

[00:25:57] If they have a reasonable suspicion to believe that you’re armed, they can conduct a pat down. for a weapon. and if that happens, and if police make an arrest, then as every criminal defendant in America does, that person has a right to challenge that evidence. on the stand. Shot Spotter’s role in that is limited we can say that gunfire occurred here at this time, but after that it’s up to the police. And so, I would say that those are the limitations of the system. We can’t tell you what the person who shot the gun was wearing, or driving, or where they went after the shooting, unless they shoot again. And very often we do detect multiple shooting incidents that are related. So those are the limitations of the technology. I don’t think, though, that’s a surprise. If you look at how law enforcement does its job, there’s no single tool that it can rely on. There are lots of tools in the toolbox. Ours is simply one, and that’s what it does.

[00:26:57] Joe Selvaggi: So, I want to go deeper again and press you a little harder there, because they say, okay, I appreciate that we don’t lose our rights merely because a shot was heard near us, right? We’re, our rights are not diminished by a Shot Shotter, in theory. But let’s imagine a policeman hears, or your technology tells the police that it has heard a shot being fired in a particular location. The police arrive. They know something bad, a shot was fired. So, you’ve got all kinds of people in every direction. They know a gun has gone off. So, immediately, their level of suspicion is higher, and also, it’s not just, they’re not spitting on the sidewalk, they’re firing guns, so they know somebody there is armed. Doesn’t that turn everybody’s spidey sense up to 11 and say, okay, everybody here is guilty until I determine they’re innocent. Isn’t this sort of inviting police to arrive, assume guilt broadly, and assume deadly force, potentially, there? It, to me, yes, of course their legal rights are not diminished, but the suspicion level is automatically higher given that you happen to be, let’s say, in the wrong place at the wrong time when a gun went off. What would you say to that? I know it’s a big question, but I’m sure our listeners are thinking it.

[00:28:06] Tom Chittum: Yeah, well, I think it’s a fair question. so, for one, I think it takes a little bit of a cynical view of law enforcement. I have been around policing my entire adult life. And what I have found is that most police are genuinely good people. Some of them are absolute heroes, but most of them just want to do a good job. They know that their work will be scrutinized in court. I think that the level of training that they get matters. but if you’ll look at the cases where Shot Spotter has been used, you’ll see that there is lots of information that police can rely on.

[00:28:42] First, let’s start with the alert itself. When we send an alert to our customers, we send audio with it. They can listen to the gunfire for themselves, and then we tell them a precise location. We’ll also include helpful tactical intelligence, like if an incident involved fully automatic gunfire or a large number of rounds being fired, so that they can prepare for that.

[00:29:07] Appropriately. Now, contrast a Shot Spotter alert to what happens with a 911 call, and I think it’s important to point out that, very often, no 911 calls come in at all. That’s one of the big gaps that Shot Spotter helps fill. But if a 911 call comes in, very often that caller has limited information. They say, I heard what I think was gunfire. It happened what I think sounded like out front. They can’t say if it’s on that block, or two blocks over, or three blocks over, the sound of gunfire will travel a long distance. So, in those situations, when, police only have a 911 call without specific details, they have no choice but to swarm the area, rove around, and see if they see something that looks suspicious.

[00:29:51] A Shot Spotter, however, gives them a precise location to start from. Now once they get there, their investigation must start, and sometimes it’s as simple as making contact with you, with people that you encounter, and say, hey, we got a report of gunfire. Did you see anything? Did you hear anything? very often, witnesses will say, yes, there was shooting, the person was wearing this or that. And so the limitation of the technology is only that we’re detecting the sound, we’re deploying them there, but what police do after that It’s up to the police, and I think, and I’ve said this many times, I don’t know that there’s been a more difficult time to be a cop, than it is today, right? The public expects the police to be faster, fairer, more transparent, more effective than ever before. But I actually don’t have a problem with that. I don’t think that the public should ever be able to hold law enforcement to a standard higher than it should hold to today itself too. And what I think we see is that a lot of police agencies are effectively using it. They’re honest brokers. They’re following the constitutional obligations that they have, and they’re only making stops when they can articulate the reasonable suspicion that Supreme Court says they must have.

[00:31:05] Joe Selvaggi: Yes, no one envies the role of a policeman, particularly in these days, this day and age. As you say, now that we have cameras and close scrutiny, police must be on their best behavior. All the time. Nevertheless, if we’re talking about, a case where suddenly, cops arrive and, let’s say they, they’ve been told by you that a shot was fired, And there’s no evidence we, they can’t figure out what happened and they do start, catching people and someone runs away and accidentally is shot, they maybe were, I don’t know, a low level drug, deal or something and they run and the police make the assumption that, that was the shooter and perhaps used deadly force on this person. How can you, deal with the, let’s say, either the political repercussions or the PR repercussions? At some level, the police wouldn’t have been there but for a shot spot or, and something bad happened. How do you inoculate yourself from what, it seems to me, inevitable that these kinds of occasions will happen? You don’t have to point to any particular case or any particular city where this may have happened, but what do you do in that situation?

[00:32:06] Tom Chittum: Well, look, I think it is awful when, police make mistakes that result in a wrongful death. As you point out, police have a lot of contact with a lot of people, and thankfully, the number of unjustifiable shootings is really low. To suggest that police wouldn’t have been there but for shot spotter, I think minimizes all of the other times where the police response was lifesaving, helped hold somebody accountable, helped get justice for a crime gun victim. Occasionally our critics will point to a couple of outlier incidents.

[00:32:42] There is one specific one, really only one in Chicago involving a young man. named Adam Toledo. Terrible circumstances. He was only 13 years old. but Shot Spotter did what Shot Spotter is supposed to do. It detected gunfire. Adam Toledo and the person he was with, were shooting in the middle of the night in, this area of Chicago and police responded.

[00:33:05] But once they got there, the shooting that occurred was really not something that Shot Spotter, was responsible for. And I would ask the question, do you think police should not respond when someone is shooting? the outlier example like that, though, really is that. And it does not minimize the hundreds of times that ShotSpotter locates gunshot wound victims, allows police to render aid, allows them to make arrests of actual shootings.

[00:33:33] In fact, you see it in Boston. If you look at headlines all across America about Shot Spotter, and you can remove the ones that are only opinion based, what you are left with is example after example of police responding to a shot spotter alert and finding gunshot wound victims, arresting offenders. And it’s because the technology really works. We are not simply getting lucky all of those times. We are alerting police to gunfire. And when shootings occur in urban areas, Timely response is important. Occasionally, the police are going to make mistakes, and that’s awful, and we should hold them to a high account. But that is not something that is Shot Spotter’s fault. Police should be investigating shooting incidents.

[00:34:18] Joe Selvaggi: Now, I’ve tried to, test you on all the sort of aspects or the sort of common criticisms of your technology, but I do want to acknowledge that there, again, I learned about this in my research, that there are, lawsuits or, made by, let’s say, the ACLU about, the general gist of their arguments is that, civil liberties are being violated. People are being over policed, or they’re being assumed to be guilty unnecessarily by virtue of the fact that they happen to be in the wrong place at the wrong time. Whether the shop herd was a valid one or not. Even if we assert that it was valid, it doesn’t make the people in the neighborhood any more suspicious than otherwise. I want to leave an open-ended question. Points do lawsuits like those from the ACLU make that I haven’t yet addressed? Where do they see weakness in your technology that I haven’t, tested you on? Well, in some ways,

[00:35:06] Tom Chittum: I think their argument is really a proxy argument. It’s not really Shot Spotter that they’re opposed to. It’s policing that they’re opposed to, and Shot Spotter is a convenient proxy for that. I think their complaint is about what some people will refer to as stop and frisk policing. And I understand that. Stop and frisk policing means that police see someone, they stop them, they pat them down for a weapon. As we talked about earlier, the Supreme Court has said, when police have reasonable suspicion to believe that a person is engaged in criminal activity, they can stop temporarily detain someone, and they can pat them down if they have reasonable suspicion to believe they have a weapon. The problem is when they stop and pat down people when they do not have reasonable suspicion that person is carrying a firearm and that would be unconstitutional in and of itself. They, I think sometimes, accuse ShotSpotter of blanketing areas with reasonable suspicion, but that simply isn’t how our technology works. Our technology locates to a precise latitude and longitude. And what the courts have said is when police show up, there are a lot of other factors that they should be assessing close spatial and temporal proximity is one. How quickly do police get there? How close is the person that they observed to where the shot spot or alert was? But there are a lot of other factors too. If a person is standing alone in that area, it’s different than if they’re being plucked from a crowd witness statement may corroborate what has happened there. And so, police have this challenging task of assessing Reasonable suspicion in stopping someone. You mentioned earlier a person that engages in unprovoked flight. They see the police, they turn, and run is one factor that police may assess.

[00:36:51] And frankly, I think police do a good job generally. the challenge with stop and frisk policing in theory, police, one, want to catch people that are illegally carrying firearms, and two, they want to, create this perception that carrying an illegal firearm is risky because police may stop you and pat you down. The downside to painting with such a broad brush is the effect it has on public support for policing. And I think that’s an important point to emphasize. The trust in law enforcement is absolutely crucial. You pointed out that gunfire is not spread evenly across our cities. It’s pretty localized.

[00:37:36] And very often people in that area know who’s responsible for the shootings, but if they don’t have faith in the police, if they don’t feel that what will happen when they call police will be just, then they won’t call, then they won’t cooperate, and I think Shot Spotter actually can help improve that too. So when shootings occur and police respond timely, it can reassure the community that police care. So, I don’t think we dug into it, but we know from research that 80 percent or more of gunfire in urban areas goes unreported to police through 911. Some of the reasons why are just practical. Many shootings happen in the middle of the night and law-abiding citizens are asleep. They may be awakened, but they don’t know exactly what it was they heard, and so they don’t call. But sometimes there are heartbreaking reasons. Some people have grown numb to the sound of gunfire and have just resigned themselves to living with it, or they think police don’t care and wouldn’t come anyways.

[00:38:36] But even though we know 4 out of 5 shootings go unreported, the average citizen doesn’t know that. And so, they hear gunfire, they look out their window, and they don’t see police show up. They think police know, but they don’t know, so they don’t come, and people lose faith. And ShotSpotter helps fill that gap and brings police there when shootings occur. And even when there is no gunshot wound victim located, and even when there’s no offender, arrested, there’s still value in having contact with the community. Knocking on doors, saying, hey, we got a report of gunfire. Just want to make sure everyone’s okay. Did you see anything? Did you hear anything? And I think low friction contacts like that can help reassure the majority of the people that live in those communities who are law abiding and who do want to see police response, that police do actually care about them.

[00:39:23] Joe Selvaggi: Yes, it’s curious to me that an organization like the ACLU that seems, its abiding concern is civil liberties, that they seem to ignore the civil liberties of the victims of crimes, right? Like, of course, we’re, I haven’t really pegged you for, pinned you down on the fact that these censors are primarily located in marginalized communities. Of course, as you say, it’s because that’s where crime happens. But of course, the people in the marginalized communities are also, are marginalized. They’re the victims of the crime that the wealthy are not being shot at. It’s often the most vulnerable. It seems odd that we are more concerned about the rights of potential criminals, and their obvious victims. I think there’s something like 20,000 murders in 2020, with guns, that’s a lot of people, so, what would you say, though, to critics that say, well, this invites over policing, now, where these signals would not have been picked up, now they are picked up, and now the police are everywhere, and people in those communities, unfortunately, you’ve got to do something about it gunshots, but they’re going to be, shaken down and brought in on, on other charges, meaning everybody in these communities is going to get locked up because someone fired a gun. What would you say to, so people who are, reflexively, concerned about, quote unquote, over policing in these communities?

[00:40:33] Tom Chittum: Well, there’s a couple of things that you mentioned there. For one, I am baffled. I really have been baffled by some of the opposition. As you mentioned, it seems that they are far more concerned about people being arrested than they are people being killed, and I just don’t understand that mindset. I also think that this perception of over-policing is largely overblown. But, to your point about gunfire not being spread everywhere, I wish that Shot Spotter was deployed all across America. If you cannot deploy it everywhere though, of course you will deploy it in the place where it can do the greatest good. And you talk about the impact in certain marginalized communities. I think an analogy is helpful. it’s well documented that Fire related deaths, not firearm, fire related deaths also occur in underprivileged, marginalized communities. And that’s because there has been disinvestment in public safety infrastructure in places like that.

[00:41:35] Shot Spotter is public safety infrastructure. The fact that it is deployed in the places where communities see the greatest gunfire, I think, is something that should be celebrated. It’s an investment in infrastructure that can help save lives. And there’s another point to make, when police respond, at a base level, Shot Spotter is just a basis for them to start an investigation. I mentioned that some of them are the rudimentary investigations. That a patrol officer would conduct. They show up to an area, they make contact with people they find, and say, hey, we got a report of gunfire. Did you see anything? Did you hear anything? but what we know from research is if police contribute, adequate follow up investigative resources to shooting incidents, they can increase their clearance rate. Now it makes sense that as a country we focus on homicide, right? That’s our worst crime and so we expect police to put the most effort into solving those. But what research shows is if they also put that sort of effort into non-fatal shootings, they can increase their clearance rate for that type of shooting, too. Non-fatal shootings are often just a failed homicide. And if you arrest and hold those offenders accountable, you prevent other shootings that they would commit. And we know that a very small number of people are responsible for most shootings. And one final point I would make. The failure to address Violent crime, in the communities where it happens most often, is, in my opinion, itself a root cause of crime.

[00:43:13] When criminals who commit violent crime feel emboldened and think they won’t be held accountable, they will commit more. And when people in those communities feel despair and don’t cooperate because they think it’s hopeless, the rate of crime increases. The quality of their life decreases. And so, I think adequately staffing, training, and supporting law enforcement, giving them tools like Shot Spotter, but other tools like ballistic imaging, focusing on improving critical tools like community support really can do a lot to reduce the crime that occurs in the communities where it happens most often. I like sitting on my front porch. I think everyone in America should feel safe sitting on theirs.

[00:44:00] Joe Selvaggi: Yes, indeed. I couldn’t agree more. I say, I don’t know how well you know Boston. I live in a neighborhood called Beacon Hill. I am certain if there was a gunshot in Beacon Hill, the Army, Navy, and Air Force Marines would be on top of it.

[00:44:09] And they would take it very seriously and they’d find the guy. That we tolerate gunshots in other communities, marginalized communities, is beyond comprehension for me. We should have zero tolerance and use any tool in our toolkit to identify. And as you mentioned, again, we maybe hit this idea too hard. Crime isn’t widespread and evenly distributed through all cities and all communities and all neighborhoods. It’s very narrowly, committed by a very few number of very determined criminals. It’s not, we’re not just finding criminals where we look. They happen to be in a particular area and you’re, and you’re looking in the right spot, now, you probably, we’re getting to the end of the time together. You hinted at the future, but I want to ask you, beyond, of course, you, you are a member of a company that you, you want to, grow your business. and so, I say you have, an incentive to want to have, Shot Spotter, everywhere.

[00:44:59] That said, let’s assume it’s not efficient, it’s not feasible. What do you see in the future of Shot Spotter or the technology like it? Do you think, again, you suggest that success begets success and failure begets failure. If we don’t catch criminals, they commit more crimes and become more emboldened. The flip side is if we lock people with guns, we all become safer and it’s a virtuous circle. What do you see the future of Shot Spotter and the future of being able to combat violent crime in the United States?

[00:45:24] Tom Chittum: So, I have three things to say. The third one will be the answer to your question. As to your previous comments, I don’t live in Boston, but I did visit recently to appear on a news program. And while I was there, I walked up to Beacon Hill. And bought a book at a bookstore. It seemed like a very safe community to me. You talked about crime not being spread everywhere, but I think it’s also important to emphasize another fact.

[00:45:51] Even though it’s concentrated in certain communities, those communities are not criminal. There are a lot of law-abiding people in those communities who want safe communities to live in. It’s a small number of people in a small number of places. And so, police really need to focus on those people in those places. That’s precision policing, and it’s something that Shot Spotter lends itself well to. You asked about the future of the company. So, as an attorney and in my role here, overseeing forensic services, every morning I get an alert about cases, case law that has mentioned Shot Spotter. This says something about me, how excited I am to read those every morning, but for months and months when I do get alerts.

[00:46:39] It’s cases that mention Shot Spotter, one time. Shots, police responded to a Shot Spotter alert, and then the case is about something entirely different. Sometimes these cases. I’ve mentioned Shot Spotter twice when there’s a footnote that says Shot Spotter is an acoustic gunshot detection system. My point for saying that is I believe that Shot Spotter is becoming routine evidence in criminal prosecutions. And I think that is a good thing. Much like the other technology, that can help make communities safer, like cameras, like ballistic imaging. what may seem newfangled really isn’t. It is, of course, important that we have appropriate policies and oversight. I also think it’s important to bring transparency to what law enforcement are doing.

[00:47:26] I don’t believe in secret policing. It’s part of the reason that we as a company very often appear in public on programs like this. To talk about what it is we do because we want the public to be informed, but I think they should be informed honestly. And when they do, I think that they will see that this is not controversial technology at all.

[00:47:45] It’s absolutely essential. It’s one tool and toolbox that can help make law enforcement more effective, can create safer communities, can hold offenders accountable, and, and can save lives. And let me conclude by mentioning that. Too often, our critics are focused on arrests, and while it is true that Shot Spotter alerts often do lead to arrests for gun related crimes, that’s not the system’s highest use. When gunfire occurs, very often there are gunshot wound victims left behind, and when you are shot, time is of the essence, and Shot Spotter gives police and first responders a precise location to get to. And we know from the experience of many of our customers that very often, Shot Spotter is the only thing that alerts them to a shooting that caused a wound.

[00:48:37] For instance, in a single year in Oakland, California, Shot Spotter led to a hundred gunshot wound victims where there was no corresponding 911 call. Those are people who would not get aid. But for the shot spotter alert. Now many of those gunshot wounds are not life threatening, and they will not die, but some of them are. And in fact, there was very recently a case like that in the Boston area, a man was shot in Dorchester, Shot Spotter alerted police, they responded. They rendered aid to him. He had life threatening injuries. The subsequent investigation allowed them to make an arrest related to that shooting. And I think that, at the end of the day, is exactly what Shot Spotter is there to do. To help police be effective, to save lives, to hold people accountable.

[00:49:22] Joe Selvaggi: Indeed. I’ll leave it there. Again, I think all of our listeners imagine a future where gun related crime is no more, this seems to be a scientific, objective, reasonable, tool to get us there, and is, that some Americans can’t walk their streets and feel safe is a tragedy and I think your technology will help Boston and other residents of cities around the country and around the globe to feel a little bit better and a little safer. Thank you very much, Tom, for joining me on Hubwonk today. You’ve been a fund of information and really, I think, have helped dispel a lot of the myths that are starting to float around, around this, what I consider really promising technology. Thank you for joining me.

Tom Chittum: Thanks for having me, Joe. I really appreciate it.

Joe Selvaggi:  This has been another episode of Hubwonk. If you enjoyed today’s show, there are several ways to support Hubwonk and Pioneer Institute. It would be easier for you and better for us if you subscribed to Hubwonk on your iTunes Podcatcher. It would make it easier for others to find Hubwonk if you offer a five star rating or a favorable review. Of course, we’re grateful if you share Hubwonk with friends. If you have ideas or comments or suggestions for me about future episode topics, you’re certainly welcome to email me at hubwonk@pioneerinstitute. org. Please join me next week for a new episode of Hubwonk.

Joe Selvaggi talks with SoundThinking’s Senior Vice President Tom Chittum about gunfire location technology promises and pitfalls when deployed by law enforcement in high-crime communities.


Tom Chittum is a lawyer, leader, and public safety executive dedicated to enhancing justice and safety in America. He is a licensed attorney and Senior Vice President at SoundThinking, a public safety technology company, where he leads a team using data and forensic tools to combat gun crime. A retired federal agent and former Associate Deputy Director of the ATF, Chittum has over 27 years of experience in law enforcement, he has conducted and overseen thousands of investigations and frequently testified as an expert witness. An adjunct professor at UNLV’s Boyd School of Law, he teaches “Firearms Law & the Second Amendment” and regularly speaks on crime and policing. Chittum holds degrees from Marshall University, Eastern Kentucky University, and the University of Nevada-Las Vegas. He is licensed to practice law in Virginia, West Virginia, and Kentucky.