4 ms·

That site says 14% of alerts result in a case report being filed and 10% result in a gun-related case report. But even a 10% alert -> case report rate is better

That site says 14% of alerts result in a case report being filed and 10% result in a gun-related case report. But even a 10% alert -> case report rate is better than I would've expected for a big city. That still seems like it'd be extremely useful, even if it means some wasted man hours. And that's case reports - not necessarily detection true positives. If someone fires a gun at the sky and picks up the shell casings and drives away, with no witnesses or cameras and an inconclusive/indiscernible audio recording, police likely won't be able to file a report. Also, I'm guessing there are some confidence indicators for each alert: those case report rates probably don't capture the full story even when accounting for hypothetical inconclusive true positives. Police are likely (and should be) obligated to investigate every detection, including every detection rated as low-confidence. Plus that's just for Chicago. I doubt they actually achieve their claimed 97% accuracy anywhere, but it could be higher in other areas. Especially areas where loud noises are less common. The main issue seems to be when it's used as evidence. I think it shouldn't ever be admissible as evidence of anything. And to mitigate some of the other issues that site raises, it'd be nice if there were some kind of "no fishing expeditions" law, where police responding to a gunfire alert must exclusively look for evidence of a fired gun in that vicinity and not use it as an excuse to scavenge for low-hanging fruit by harassing / arresting people in the area for unrelated matters.

giantg2 5y ago
"That still seems like it'd be extremely useful, even if it means some wasted man hours." I think the least wasteful approach would be to build rapport with the community and rely on their reports. Probably not an easy thing, but the most valuable things rarely are.
- whimsicalism 5y ago
  Still doesn't stop the phenomena of everyone thinking "oh, someone else will call." Shotspotter is a very useful tool IMO.
  - pessimizer 5y ago
    > the phenomena of everyone thinking "oh, someone else will call." This generally doesn't happen. It originated as a slander against the people who lived around where Kitty Genovese was killed, as an after-the-fact excuse for the lack of police response. > While there was no question that the attack occurred, and that some neighbors ignored cries for help, the portrayal of 38 witnesses as fully aware and unresponsive was erroneous. The article grossly exaggerated the number of witnesses and what they had perceived. None saw the attack in its entirety. Only a few had glimpsed parts of it, or recognized the cries for help. Many thought they had heard lovers or drunks quarreling. There were two attacks, not three. And afterward, two people did call the police. A 70-year-old woman ventured out and cradled the dying victim in her arms until they arrived. Ms. Genovese died on the way to a hospital. https://en.wikipedia.org/wiki/Murder_of_Kitty_Genovese#Accuracy_of_original_reports https://en.wikipedia.org/wiki/Murder_of_Kitty_Genovese#Accur...
    - whimsicalism 5y ago
      There's evidence around how the majority of gunshots in most cities are not followed by 911 calls. For instance, the murder of Seth Rich in my home city (ignore the stupid conspiracy theories) was not followed by a call but was found by shotspotter which is how it was responded to.
    - meowface 5y ago
      Just because that particular story was a myth doesn't mean the bystander effect isn't a real phenomenon. Also, that's still two out of 38 people who called. If only 36 people were there, without those two, it's possible no one might have called.
- meowface 5y ago
  Obviously that's also necessary, but even if you have the best possible rapport and reputation with the community, you won't always get a report. Also, even the fastest report will be slower than a gunfire detector report.
nitwit005 5y ago
It's hard to tell, as many of those cases may have been created anyways. That is, you may get an alert and 911 calls about the incident. You'd need to subtract all those cases from the rate to see the improvement. This tends to be the issue with a lot of "AI" technology tied to police work. It does work to some extent, but it mostly tells you things you already know.
- meowface 5y ago
  That's very true. Though, while accounting for that, it's also shown that gunfire detectors result in faster response times as well. So even if police were to have received a 911 report, the gunfire alert still could've led to them getting there faster than they would have otherwise.
  - ashtonkem 5y ago
    > Though, while accounting for that, it's also shown that gunfire detectors result in faster response times as well. That seems incompatible with roughly nine out of ten shotspotter reports ultimately being false positives.
    - meowface 5y ago
      What do you mean? I was referring to faster response times to true positive shootings. I can see how it sometimes might indirectly lead to slower response times to other kinds of crime, but I imagine probably not violent crime, unless they have awful triaging.
      - ashtonkem 5y ago
        Two things: 1) False positives lead to under reaction. This is the "boy who cried wolf" issue. 2) Extra false positives put strains on resources, as they produce spurious false reports that must be dealt with in parallel with other requests. Combine these two, and I'm dubious that shotspotter would actually make the police more responsive to real shootings.

giantg2 5y ago

"That still seems like it'd be extremely useful, even if it means some wasted man hours." I think the least wasteful approach would be to build rapport with the community and rely on their reports. Probably not an easy thing, but the most valuable things rarely are.

whimsicalism 5y ago
Still doesn't stop the phenomena of everyone thinking "oh, someone else will call." Shotspotter is a very useful tool IMO.
- pessimizer 5y ago
  > the phenomena of everyone thinking "oh, someone else will call." This generally doesn't happen. It originated as a slander against the people who lived around where Kitty Genovese was killed, as an after-the-fact excuse for the lack of police response. > While there was no question that the attack occurred, and that some neighbors ignored cries for help, the portrayal of 38 witnesses as fully aware and unresponsive was erroneous. The article grossly exaggerated the number of witnesses and what they had perceived. None saw the attack in its entirety. Only a few had glimpsed parts of it, or recognized the cries for help. Many thought they had heard lovers or drunks quarreling. There were two attacks, not three. And afterward, two people did call the police. A 70-year-old woman ventured out and cradled the dying victim in her arms until they arrived. Ms. Genovese died on the way to a hospital. https://en.wikipedia.org/wiki/Murder_of_Kitty_Genovese#Accuracy_of_original_reports https://en.wikipedia.org/wiki/Murder_of_Kitty_Genovese#Accur...
  - whimsicalism 5y ago
    There's evidence around how the majority of gunshots in most cities are not followed by 911 calls. For instance, the murder of Seth Rich in my home city (ignore the stupid conspiracy theories) was not followed by a call but was found by shotspotter which is how it was responded to.
  - meowface 5y ago
    Just because that particular story was a myth doesn't mean the bystander effect isn't a real phenomenon. Also, that's still two out of 38 people who called. If only 36 people were there, without those two, it's possible no one might have called.
meowface 5y ago
Obviously that's also necessary, but even if you have the best possible rapport and reputation with the community, you won't always get a report. Also, even the fastest report will be slower than a gunfire detector report.

nitwit005 5y ago

It's hard to tell, as many of those cases may have been created anyways. That is, you may get an alert and 911 calls about the incident. You'd need to subtract all those cases from the rate to see the improvement. This tends to be the issue with a lot of "AI" technology tied to police work. It does work to some extent, but it mostly tells you things you already know.

meowface 5y ago
That's very true. Though, while accounting for that, it's also shown that gunfire detectors result in faster response times as well. So even if police were to have received a 911 report, the gunfire alert still could've led to them getting there faster than they would have otherwise.
- ashtonkem 5y ago
  > Though, while accounting for that, it's also shown that gunfire detectors result in faster response times as well. That seems incompatible with roughly nine out of ten shotspotter reports ultimately being false positives.
  - meowface 5y ago
    What do you mean? I was referring to faster response times to true positive shootings. I can see how it sometimes might indirectly lead to slower response times to other kinds of crime, but I imagine probably not violent crime, unless they have awful triaging.
    - ashtonkem 5y ago
      Two things: 1) False positives lead to under reaction. This is the "boy who cried wolf" issue. 2) Extra false positives put strains on resources, as they produce spurious false reports that must be dealt with in parallel with other requests. Combine these two, and I'm dubious that shotspotter would actually make the police more responsive to real shootings.