* Press release…
The City of Chicago Office of Inspector General’s (OIG) Public Safety section has issued a report on the Chicago Police Department’s (CPD) use of ShotSpotter acoustic gunshot detection technology and CPD’s response to ShotSpotter alert notifications. OIG concluded from its analysis that CPD responses to ShotSpotter alerts can seldom be shown to lead to investigatory stops which might have investigative value and rarely produce evidence of a gun-related crime. Additionally, OIG identified evidence that the introduction of ShotSpotter technology in Chicago has changed the way some CPD members perceive and interact with individuals present in areas where ShotSpotter alerts are frequent.
OIG issued its descriptive analysis on the outcomes of ShotSpotter alerts to provide the public and City government officials—to the extent feasible given the quality of the Office of Emergency Management (OEMC) and CPD’s data—with clear and accurate information regarding CPD’s use of ShotSpotter technology. ShotSpotter is a gunshot detection system that uses a network of acoustic sensors to identify and locate suspected gunshots, and currently operates in more than 100 U.S. cities. Chicago’s $33 million, three-year contract with ShotSpotter began on August 20, 2018; in December 2020, well before the end of the contract term, the City exercised an option to extend the contract, setting a new expiration date for August 19, 2023.
The CPD data examined by OIG does not support a conclusion that ShotSpotter is an effective tool in developing evidence of gun-related crime. If this result is attributable in part to missing or non-matched records of investigatory stops that did take place as a direct consequence of a ShotSpotter alert, CPD’s record-keeping practices are obstructing a meaningful analysis of the effectiveness of the technology.
OIG analyzed data collected by CPD and OEMC regarding all ShotSpotter alert notifications that occurred between January 1, 2020, and May 31, 2021, and investigatory stops confirmed to be associated with CPD’s response to a ShotSpotter alert. OIG’s analysis of OEMC data and investigatory stop report (ISR) data revealed:
• A total of 50,176 ShotSpotter alerts were confirmed as probable gunshots, issued an event number—a unique record identification number assigned to distinct “events” of police activity—and dispatched by OEMC; each of these resulted in a CPD response to the location.
• Of the 50,176 confirmed, 41,830 report a disposition—the outcome of the police response to an incident. Of those dispositions, a total of 4,556 indicate that evidence of a gun-related criminal offense was found, representing 9.1% of CPD responses to ShotSpotter alerts.
• Among the 50,176 confirmed and dispatched ShotSpotter alerts, a total of 1,056 share their event number with at least one ISR, indicating that a documented investigatory stop was a direct result of a particular ShotSpotter alert. That is, at least one investigatory stop is documented under a matching event number in 2.1% of all CPD responses to ShotSpotter alerts.
• Through a separate keyword search analysis of all ISR narratives within the analysis period, OIG identified an additional 1,366 investigatory stops potentially associated with ShotSpotter alerts whose event number did not match any of the 50,176 confirmed and dispatched ShotSpotter alerts.
OIG’s analysis of ISR narratives further revealed that the presence of the technology is changing police behavior. Specifically, OIG reviewed instances in which CPD members rely, at least in part, on a perceived aggregate frequency of ShotSpotter alerts in an area to form the basis for an investigatory stop or as part of the rationale for a pat down once a stop has been initiated. Additionally, better data on law enforcement outcomes from ShotSpotter alerts would be valuable to support the City’s future assessments of whether to extend, amend, or discontinue its contractual relationship with ShotSpotter.
“Our study of ShotSpotter data is not about technological accuracy, it’s about operational value,” said Deputy Inspector General for Public Safety Deborah Witzburg. “If the Department is to continue to invest in technology which sends CPD members into potentially dangerous situations with little information––and about which there are important community concerns–– it should be able to demonstrate the benefit of its use in combatting violent crime. The data we analyzed plainly doesn’t do that. Meanwhile, the very presence of this technology is changing the way CPD members interact with members of Chicago’s communities. We hope that this analysis will equip stakeholders to make well-informed decisions about the ongoing use of ShotSpotter technology.”
The full report is here.
- Homebody - Tuesday, Aug 24, 21 @ 9:30 am:
== CPD’s record-keeping practices are obstructing a meaningful analysis of the effectiveness of the technology ==
This always seems like a common thread so many things with law enforcement (and defense/national security contractors as well). They make bold claims, but can’t prove any of their claims. Then the record keeping is so bad, you can’t even actively disprove their clearly made up claims.
- Telly - Tuesday, Aug 24, 21 @ 9:52 am:
The overwhelming majority of calls that police officers are dispatched to “don’t produce evidence of a crime.” Talk to any patrol office and they’ll tell you responding to a burglar alarm call for which there is no burglar is an every day occurrence. And calls come into 911 all the time about suspicious persons or activity and when the officer gets to the scene they find nothing. Those kind of calls can also result in a pat down of an innocent person — just like Shotspotter calls.
That little bit of context is important to any meaningful analysis of Shotspotter.
- ;) - Tuesday, Aug 24, 21 @ 9:58 am:
What world is the OIG living in?
- WestBurbs - Tuesday, Aug 24, 21 @ 10:14 am:
Lots of questions about this report. How do they determine that “50,176 ShotSpotter alerts were confirmed as probable gunshots?” And how many “alerts” were not confirmed as probable gunshots? I think this is the KEY stat they should be looking at - is SS accurately detects gunshots then it likely is valuable technology. How CPD uses that tech is a separate, important question? But, first, need to determine if SS is accurate.
- Amalia - Tuesday, Aug 24, 21 @ 10:14 am:
I suppose the OIG would report that the license cameras that are going up do not produce enough results. Telly has the spot on perspective.
- Asteroid of Caution - Tuesday, Aug 24, 21 @ 10:26 am:
Or you could just read/listen to the enterprise reporting that reached the same conclusion about 5 years ago.
https://revealnews.org/blog/shotspotter-not-exactly-taking-a-bite-out-of-crime/
- Nick - Tuesday, Aug 24, 21 @ 10:57 am:
There was a Vice article not to long back about how police, including in Chicago, sometimes have had ‘evidence’ from shotspotter altered
https://www.vice.com/en/article/qj8xbq/police-are-telling-shotspotter-to-alter-evidence-from-gunshot-detecting-ai
Inaccurate and ineffective technology which is another giveaway of public funds, by the looks of it
- Miso - Tuesday, Aug 24, 21 @ 11:08 am:
a total of 4,556 indicate that evidence of a gun-related criminal offense was found, representing 9.1% of CPD responses to ShotSpotter alerts
A 10% return is = “rarely provides evidence”? What exactly are you smoking? 4,500 cases where evidence was recovered? Tell me, do violence interrupters and the millions we spend on them have better statistics than 10% (in their case) reduction in shootings? If it is only a 10% reduction, should we stop funding them too?
Such a goofy piece.
- Moved East - Tuesday, Aug 24, 21 @ 11:17 am:
Miso, how is there a 10% reduction in shootings? The shots already occurred. Also, police don’t usually respond all nice like to a possible shooting, so how would you like to live in a neighborhood where the full SWAT and force come in guns blazing, but it is for nothing 90% of the time?
- cermak_rd - Tuesday, Aug 24, 21 @ 12:04 pm:
By what right do the police have to pat down people they are not arresting? At least they should have clearly defined boundaries where they can and cannot order a pat down and have that promulgated to the public so people know how to avoid it.
- Da Big Bad Wolf - Tuesday, Aug 24, 21 @ 12:05 pm:
Maybe shot spotter is poor for gathering evidence. But police can get to the victims faster and maybe save their lives
- Da Big Bad Wolf - Tuesday, Aug 24, 21 @ 12:22 pm:
=== Tell me, do violence interrupters and the millions we spend on them have better statistics than 10% (in their case) reduction in shootings? If it is only a 10% reduction, should we stop funding them too?===
If violence interrupters prevent a murder that is far better then the murder happening and then the police catch the murderer. So no we shouldn’t stop funding them.
- Nick - Tuesday, Aug 24, 21 @ 12:23 pm:
There’s no evidence that it actually increases response times, or that it lets them reach victims faster, in the event it actually leads to discovering a victim.
In fact there’s not really much of any evidence of its effectiveness at all.
- Three Dimensional Checkers - Tuesday, Aug 24, 21 @ 1:03 pm:
It’s a much better use of a patrol officer’s time to go where a shooting may have just occurred than other uses of a patrol officer’s time (snark absolutely intended). I am not going to speculate on how many of those dispatches should result in police reports. That depends on the facts of each dispatch. If there were police reports in 50% of these event numbers, people would be saying that’s too many police reports.
- Da Big Bad Wolf - Tuesday, Aug 24, 21 @ 1:06 pm:
===There’s no evidence that it actually increases response times, or that it lets them reach victims faster, in the event it actually leads to discovering a victim.===
Here: https://www.post-gazette.com/news/crime-courts/2021/06/15/shotspotter-alert-pittsburgh-data-first-responders-shooting-victims-gunshot-locations-911-police-ems/stories/202106150161
- Dotnonymous - Tuesday, Aug 24, 21 @ 1:15 pm:
It was effectively profitable…for someone…if you follow.
- Thomas Paine - Tuesday, Aug 24, 21 @ 1:45 pm:
If the Department of Human Services paid a contractor $30 million to deliver meals on wheels and an inspector general report showed that only 2.1% of those meals actually got to intended recipients, those of you defending CPD and Shot Spotter would be calling for the contractor to be fired, the DHS director to resign, and criminal charges.
Unless I am mistaken, the purpose of shot spotter is to catch gun criminals, not assist gun crime victims. If it were the latter, we would roll the meat wagons into the area whenever a Shot Spotter alert came in, and that is not what we do.
Police departments hate data because they like to ignore real info and “go with their gut” whether making a traffic stop, searching a suspect, entering a high speed chase, or using deadly force.
Also, their gut is telling them not to get vaccinated for COVID.
Shot Spotter is a waste of money we can no longer afford.
- A Jack - Tuesday, Aug 24, 21 @ 1:52 pm:
If you missed it, there was a Tribune article a few days ago about Michael Williams being jailed last year over inconclusive Shot Spotter evidence. Shotspotter, Red Light cameras, how much freedom do we need to give up to be marginally safer?
- WestBurbs - Tuesday, Aug 24, 21 @ 5:01 pm:
Moved East — assuming SS is accurate - meaning shots were actually fired - then cops on the scene are “not for nothing.” Why is it any different than somebody calling 911 to report shots fired - should cops not respond to the 911 call because, as I suspect is true, 90% of the time they don’t make an arrest.
cermak_rd - there are “clearly defined boundaries” laid out publicly by Supreme Court since 1968 - its called a “Terry” stop — Wikipedia summarizes it correctly as - A Terry stop in the United States allows the police to briefly detain a person based on reasonable suspicion of involvement in criminal activity. Reasonable suspicion is a lower standard than probable cause which is needed for arrest. When police stop and search a pedestrian, this is commonly known as a stop and frisk.
- WestBurbs - Tuesday, Aug 24, 21 @ 5:32 pm:
All of you seem to be avoiding the real questions. 1. Does SS accurately detect gunshots, and by accurate” I mean false positives under 20%? 2. if accurate, shouldn’t the cops investigate a highly probable report of gun shots? Why is SS different than a 911 call? Is this just a money issue for you guys? Or are you worried about cops overreacting? Seriously, I don’t understand the complaints.