Some sort of software analysis performed by SoundThinking identifies a possible gunshot. The audio recordings are sent to a human analyst, a SoundThinking employee, who reviews the recording and enters an assessment of what it contains (e.g. if it is gunfire, and how many rounds). If the analyst confirms the report, an alert is sent as a text message (I believe in an app they furnish) to staff in APD's dispatch center, called the Emergency Communications Center (ECC). The contract includes an SLA on this process of I think 1 or 2 minutes, but I was told that they routinely performed as well as 30 seconds. Some APD personnel, I think usually area commanders but it may have been all field division sergeants, also receive the alerts on their phones.
The ECC dispatches the call as a priority 2. P2 is high enough that a ShotSpotter report will "bump" most calls for service except for a caller on the line violent crime in progress. When the officers arrive at the reported location, they make a brief assessment and search the area for suspects or victims. If no suspects or victims are found, a Crime Scene Technician is dispatched (often later as they will wait for daylight) to search the area for evidence such as spent shell casings.
My recollection is that I was told they were able to find definitive evidence of actual shots fired in less than five percent of cases, but take that with a grain of salt as I do not believe it was ever put in writing (I don't think they're allowed to by their contract) and I could be remembering wrong. However, it's believable that the accuracy of the system is higher than that suggests, as Albuquerque has a lot of wide open spaces that are difficult to search thoroughly if the ShotSpotter location estimate is at all inaccurate.
I was told that, when the system was tested by firing blanks, it was not completely effective but that they were satisfied with how effective it was. I was never given a number and I think they had been very specifically prohibited from discussing the testing in detail when they coordinated it with SoundThinking.
One of the major criticisms of the ShotSpotter system in Albuquerque is that it results in a relatively large volume of P2 calls that delay police response to most other calls for service. During the worst of the understaffing, I was told that some officers in high-crime areas like the International District spent a large portion of their total shift following up on ShotSpotter activations while there were multiple P3 calls queued. This has probably improved as staffing levels have increased, but in my mind it is the greatest single concern about the system.
SoundThinking's evasiveness, refusal of independent research, and clear motive to sell their product creates an alarming possibility that they are deceiving police leadership and elected officials into overprioritizing ShotSpotter. It may be a waste of money, which is already a problem, but the much greater concern is that police departments are putting off responding to nonviolent crimes in progress to go to ShotSpotter reports instead, because they have been told by SoundThinking that the accuracy rate of the system is very high.
Wow that's even worse than what I had read from reports about the deployment in Chicago (which I read up on when Seattle was considering it). I think the value was like 10%.
Chicago also ditched it recently I think.
Though at the end of the day it doesn't really matter. The brass I mean. Finding brass or not finding brass doesn't exactly help catch or prosecute someone shooting a gun illegally. The whole point was to more quickly catch crimes in progress, and it doesn't seem like that's working.
All that being said, the metrics are horribly flawed because they assume police will actually investigate anything after dispatch and that the investigation will turn anything up. Believing that CPD is going to case a neighborhood looking for GSR and shell casings with a forensics team is a tall order. If there isn't someone bleeding out in the street there probably isn't going to be a police report filed.
And even that said - ShotSpotter is useless because it requires police to do their job to be useful. When Reddit is better at tracking gang violence than cops, no fancy audio forensics tool is going to help.
(1) https://www.npr.org/2024/02/15/1231394334/shotspotter-gunfir...
Kind of. The mayor said he was shutting it down for not being effective. And then he went and renewed the contract until just after the DNC convention: https://chicago.suntimes.com/city-hall/2024/02/22/shotspotte...
My read is that they know it does work but they don’t want to continue to use it because statistically the “wrong” people are committing the crimes it’s tipping off.
Your read is dumb as shit.
https://medium.com/@kim_94237/tdoa-sound-localization-with-t...
and with manual input you can greatly improve the accuracy from what an automatic system could do due to noise and signal degradation. However it’s very time consuming. The service level response would not be met if doing this on many cases I’m sure. Meaning the default accuracy of localization is likely to be a bunch less accurate than what it could be in theory.
What is absolutely needed is to start a validation process. Start legal proceedings to force the disclosure of co-ordinates and exact event time information as recorded by each recorder so the math can be checked. My software will provide that side.
I did wonder about finding mice. I connected an ultra-sonic microphone once and saw lots of squeaks that were probably mice. I suspect the accuracy is sufficient.
Less than five percent seems unlikely, but I wouldn't be surprised to hear "less than half the time".
Not finding evidence is a different problem, it could be as simple as using a revolver rather than a semi-auto that ejects the cartridges.
In any case, it would be great to see independent testing of this problem by the sort of people in this forum and you can use the software I developed last year (https://github.com/hcfman/sbts-aru) to do so. That software sets the time on the Raspberry Pi to have less than 1 microsecond of error, which is more than enough for any validation efforts.
> The reader can probably infer how this coverage pattern relates to race and class in Albuquerque. It's not perfect, but the distance from your house to a ShotSpotter sensor correlates fairly well with your household income. The wealthier you are, the less surveilled you are.
This sets off the bs alarms to me. The author knows this is a gross distortion of the rationale and is playing dumb. So what else are they lying about?
1. Cops use enforcement on poor neighborhoods because they like to make their lives difficult and because they hate poor people
2. Cops use enforcement there because that's where the crimes take place
Explanation 2 is so obviously much more likely that I can't take the person that purports reason #1 without acknowledging the other explanation. They're playing dumb.
1) Why is this conversation happening in this subthread? What does this have to do with nonrandomstring's experience in doing similar work for the military?
2) Nothing in the passage you quoted insinuates anything about the reasoning for surveiling poor neighborhoods more than rich. It simply points out that this is a thing that is happening.
Earlier they said this:
> Many assumed that ShotSpotter coverage was concentrated in disadvantaged parts of the city, an unsurprising outcome but one that could contribute to systemic overpolicing.
It's unsurprising because that is where the crime tends to take place, but there's a valid concern raised that this is a self-fulfilling prophecy.
I've read some highly political anti-police rants in the past few years, but this isn't one of them. The author barely makes their opinions known at all, and when they do they're very aware of the complexities.
Cops cause crime? Again, the post wasn't necessarily about that but a statement like the one I originally quoted and the one you just said sets off my detector that you're either flat earth level delusional or not arguing in good faith. Good bye
3. Cops use performative enforcement in poor neighborhoods because it yields metrics important to them with minimal effort.
Poor neighborhoods are often demanding and crying out for enforcement of laws. Nobody wants to live next to a crackhouse, and the people forced to lack options to leave. In my city, there's a notorious drug house that has been in operation since I was in college in the 1990s. It has better staying power than Walmart -- it's still there. What poor people in general resent to the point of riot about is systematic bullshit and abuse on the part of ineffective police.
When the powers that be say "clean up that area", they round up stupid kids for bullshit, maybe hit up a few street dealers, etc. The actual hard work, say arresting street gang leadership or investigating property crimes isn't sexy and takes time. The best documented examples are NYPD, where the worship of Excel sheets resulted in sweeps where the cops would issue appearance tickets for such offenses as "obstructing the public sidewalk" (ironically doing so, btw, when they are literally parking their personal vehicles on sidewalks for these big sweeps), than run through and make arrests for failure to appear a few months later.
Shotspotter in particular is stupid - it's just a way to blow Federal grant money. If as you say, the police "know where the crime is", why would they need microphones to tell them where gunshots go off? Presumable they patrol high risk areas and hear it themselves.
Police departments are paramilitary organizations. That means they need a military like level of accountability and discipline to function well, and the nature of modern governance is such that that is lacking. The Army doesn't tolerate drunken soliders runing amok, but police departments do. IMO the best way to address the issues of policing is to consolidate smaller departments into state or regional entities to both professionalize and reduce the chummy nature of what goes on.
Shotspotter is useless (5% is at best par for the course for every intelligence appliance I've used myself) but your expectations are unrealistic.
You're berating them for shaking down street kids for intelligence, then berating them for not taking down gang leaders? Lmao.
That's an impossible situation you've created. How about you demonstrate how policing should be done?
> why would they need microphones to tell them where gunshots go off?
Not where, when.
Writing tickets for blocking sidewalks is an overtime generating detail, not intelligence. It’s “objective” in the sense that everyone gets harassed, and thus safer than using discretion to do something potentially intelligent.
I assumed someone was raising a technical objection to my claim that acoustic location of transient sounds is "hard" - myself being the "expert" having published on firearm signatures and machine listening.
But this is about the socio-politics in TFA. Okay.
Would it report if you were playing Counterstrike outside with speakers on? What if you were listening to some gangster rap with shots in it? Or just a Raspberry Pi with a speaker on with gunshot? It seems to me something like this can in theory DoS the ECC.
It seems an important piece of context if you are concerned about surveillance.
Further, the concern is unequal policing biases statistics resulting in more uneven policing. A grid of microphones covering a full city is unbiased, placement based on past data isn't.
Drug crime is known to be fairly evenly distributed across different incomes, arrests are extremely biased.
[1] "New Bedford utilized ShotSpotter, and the following was recorded by the gunfire detection system: “‘Oh my God! You're crazy!’ and then ‘Jason don‘t!’ several times, followed by a number of gunshots. After the gunshots, a female was heard yelling ‘You . . . missed and they shot him!’ ‘You're going to jail!”’. A motion to suppress this evidence was granted in Denison’s case, as the judge ruled that the ShotSpotter recording violated the Massachusetts Wiretap Act" https://readingroom.law.gsu.edu/cgi/viewcontent.cgi?article=...
"In the 2015 Massachusetts case, the court refused to allow the introduction of ShotSpotter audio after the defendant argued the audio was captured and obtained in violation of that state’s wiretap laws. Police in that case requested and received an extended audio clip from the company that captured people discussing the shooting, including one calling out the defendant’s name."
In theory any evidence from those audio recordings is tainted and no longer admissible, therefore police should want to avoid listing to any of it. But... by not bringing it up in court police can use parallel construction to get around those issues.
https://www.policingproject.org/shotspotter
https://www.shotspotter.com/wp-content/uploads/2021/01/ShotS...
> Drug crime is known to be fairly evenly distributed across different incomes, arrests are extremely biased.
Keep in mind that the reverse is true for gun crime, where low-income minority communities suffer from the lowest clearance rates.
PS: You are quoting my previous post not an edit: "Drug crime is known to be fairly evenly distributed across different incomes, arrests are extremely biased." is from further up the thread.
Are shooting crimes known to be fairly evenly distributed across different incomes?
I'm reasonably concerned that once recordings exist getting access to them is much easier, especially as police have already heard many conversations taken from these recordings.
https://twitter.com/loteck/status/1760859493133697237?t=AQTP...
The detection of gunshots is based on an algorithm. When triggered, it saves a few seconds before the sound and several seconds afterward.
It is different than police just being able to pull up the recordings for a certain street corner from 2 weeks ago or even a day ago and listen in on people's conversations. The case in question came from a shotspotter recording gunshots, and the short clip also happened to include speech within it since it directly followed the sound of shots.
For convenience, the most relevant text: "If the system misses a gunfire incident, police may contact the company to see if there is any audio or location evidence. In this case, only authorized ShotSpotter personnel with proper credentials can access sensor audio to search. Their search is limited to the 30- hour sensor storage timeframe."
ShotSpotter used to have significantly fewer privacy protections, and retention was indefinite early in the product's life. Fortunately, a combination of legal challenges and statutory privacy policies among their customers have lead to them significantly improving their privacy controls over time.
I'm curious what your source for that information is
I actually strongly disagree with you — the context doesn’t matter. We have a private quasi-law enforcement entity installing thousands of surveillance devices in American cities without any external oversight or knowledge of where they are installed. These surveillance devices that were pitched as tools to locate gun crimes all of a sudden record audio? And this quasi-law enforcement company with no oversight is storing that data and then furnishing it to the police?
We have no idea what’s recorded, we have no idea where these devices are, we have no idea who is listening to the recordings, we have no idea what access LEOs have to these recordings, we don’t know how they are stored, and we don’t know how long they are stored for. You’re seriously okay with a non-government entity operating like this?
You even talk about how a school where some little kid got shot has a sensor, as if it's some sort of punishment for the lower income people there. Perhaps it's because the police and the city government want to deter or solve murders that happen. The way your article is framed, the main concern is that low income or minority perpetrators of shootings might get caught and put in jail. The fact that minority or low income victims of major violent crime might have their assailants deterred or at least brought to justice does not even factor into your calculus.
> In fact, large majorities of residents in low-income “fragile communities” — including in both urban and rural areas — want more police presence, not less. In the more than a dozen low-income urban areas surveyed, 53% of residents want more police presence while 41% want the same — only 6% want less.
Not being shot is pretty low on the hierarchy of needs. And let's be real, it's a tiny percentage of people that are committing violent crime. Increasing the odds of correctly putting one person in jail prob reduces future crime greatly.
The criminal element is real and I'm doubtful that you can give someone who's killing people access to a food bank or job training and they'll just become a productive member of society. Being a violent criminal is almost certainly the least economical thing you can do. You end up killed or in jail in a short time span so to think someone rationally picks this as a career opposed to a minimum wage job is not realistic.
https://www.usatoday.com/story/opinion/2020/08/26/why-americ...
But ARE you though? I'm in Chicago where we're in the tail end of phasing this system out specifically because it did not address the problems it claimed to. All it did was aggravate and harass locals _after_ the fact that had nothing to do with the initial crime.
The deterrence factor was not insignificant, but it definitely wasn't worth the far greater instances where it was not only creating false positives but also proactively CREATING crime in accordance with other "high tech" solutions like predictive crime algorithms which only really served to reinforce existing biased patrolling practices (which were driven by data generated by shot spotter, in part).
See: https://www.theverge.com/c/22444020/chicago-pd-predictive-po...
People want more, better-trained police, not a third party listening in and directing police resources based on biased data, proprietary algorithms, and human analysts with dubious training and no public accountability.
All you’re telling me is that you lack human empathy and aren't interested in understanding the systemic causes of violence.
I'm pretty sure we should start arresting people who kill other people and remove them from society. Pretty high on priority
“Funding for programs that clean and rehabilitate blighted and abandoned property are associated with both decreases in gun violence of up to 39% over one year and improved community health.” https://publichealth.jhu.edu/center-for-gun-violence-solutio...
To be fair after checking SoundThinking’s website they do have some research showing similar levels of violence reduction, so I don’t think it’s fair to outright claim one is more effective on a per-dollar basis without knowing all the associated costs. However surveillance is a reactive solution (or a deterrent if you’re really on board with a police state), whereas community-based programs are preventative.
I can see there being room for both but any public surveillance on that level has to have serious public accountability.
There’s a bit of a chicken and egg problem here nobody wants to wrestle with: 1. Poor people commit the vast majority of violent crime. 2. People with records of convictions of violent crime cannot get stable employment. 3. There is a measurable intelligence and emotional regulation gap at the average between violent criminals and productive members of society. 4. There is a measurable intelligence gap associated with income in our modern knowledge-based society. 5. Inability to get stable employment and low impulse control both are major contributing factors to recidivism.
It’s a heavily intractable problem, it’s clear retributive justice is not as effective as rehabilitative justice, but creating a feeling of duty of care in the communities harmed by crime is a nearly impossible ask. Gentrification at least provides a way out to improve communities for those residents who can afford to stay.
Does ShotSpotter prevent shootings? Does it suppress would-be shooters? $5M can go a long way to do good in a community. Effectiveness of systems that taxpayer dollars purchased should be transparent. If there isn't transparency in these systems then they should have to be paid for out of pocket. And that means that since law enforcement doesn't sell services they would have to raise the money publicly and sell citizens on the improvements that the system would bring to those residents.
The fact that you had to post what you did with a throwaway speaks volumes about your self-awareness of your position and how it would resonate. Feels good to be able to choose privacy, right?
Unless you're the police then you just do whatever you feel -- I'm scared! Should we get another tank?
I caught it at the Omaha Film Festival and it has caused me to take a second look at the way our cities are organized in to "good" and "bad" parts.
In the country with 21,000 homicides a year, it's hard to ignore the connection to attachment disorders while watching people wring their hands and make up exotic concerns that would be more fit for a Ray Bradbury novel over anything designed to address the world leading rates of violent gun crime, up to and including the literal concept of laws and the enforcement of those laws.
I don't know what the solution here is, because I don't know how you send an entire country to therapy and/or Al-Anon, but not continuously enabling the people that are hurting us is a great start, and that necessarily requires shifting empathy from the people that don't deserve it (violent criminals) to the people that do (their traumatized victims).
Apologies for the throwaway account but a lot of people get ridiculously emotional over this topic, and that's when I'm not accusing them of being societally co-dependent.
Are these areas also the ones where the majority of crime takes place or not? If there exists such correlation then why bring it up? If the gun crime is the foremost issue then are you arguing that the "disadvantaged parts" should be left on their own to deal with the issue?
Historically, APD's use of pervasive surveillance technology has been a flashpoint in the debate. APD has live access to perhaps 3-4 thousand cameras across the city (they aren't very transparent about this and it depends on how far along the APS integration project is), they have used facial recognition against driver's license photos and other sources since 2014, they have installed ALPR throughout the city and recently expanded retention to one year, etc. This is all fed into the Real-Time Crime Center, which uses a data fusion product from a vendor called Genetec to provide sort of a futuristic point-and-click data system that combines ShotSpotter detections with video feeds with service call records etc. to produce sort of a dossier on any given person or location.
Unfortunately, there are a lot of things going on in city politics, especially with regard to crime and policing, and so the topic of surveillance has mostly fallen out of public attention.
Still, APD's refusal to say in any detail what parts of the city were covered by ShotSpotter has been one of the big ongoing frustrations, particularly among those who favor police reform. I mostly wrote this article to highlight that there is finally information on the matter available. The concerns about how distribution of sensors and, more broadly, use of surveillance technology impacts civil rights and quality of life in the city are mentioned mainly as an aside and I do not attempt to articulate the pros and cons. That would require a rather lengthy piece as the topic is complex, and currently the greater part of the controversy isn't even about the wisdom of deploying ShotSpotter, but rather over whether or not ShotSpotter even works (and, consequently, whether or not it's simply a waste of city money, at a rate of around $5 million).