How First Responder Trauma Response Gives a More Complete Picture about the Value of Gunshot Detection
In August of 2021, the Chicago Office of the Inspector General (OIG) published a report on the Chicago Police Department’s use of ShotSpotter’s gunshot detection system during the period of January 1, 2020, and May 31, 2021. While the OIG report relied on data that does not tell the complete picture of the outcome of ShotSpotter alerts, it did not challenge the technical efficacy of ShotSpotter in accurately detecting and alerting on gunfire. The report could have gone further in its analysis to present a broader understanding of operational and community value. The following analysis is meant to build upon the OIG report, using the same data to provide additional context to help provide a more complete picture of the value of gunshot detection and drive a more constructive dialogue.
I. 911 vs. Acoustic Gunshot Detection
The principal critique of ShotSpotter in the OIG report is that ShotSpotter alerts led to a non-criminal incident disposition coded as 19A, 19B or 19P by the Chicago Office of Emergency Management and Communication (OEMC) 84% of the time. These coded dispositions suggest there was no physical evidence and/or on-scene human witness confirming that a gun-crime was committed that could be reported by the on-scene dispatched patrol officers. However, when we compare the efficacy of traditional 911 shots fired calls for service from the community during the same period within the same coverage area, the OEMC data shows it has essentially the same non-criminal disposition rate as ShotSpotter at 85%¹. While that percentage may sound high to civilians, we know from our work with over 100 agencies that the vast number of calls for service for shootings do not end up with a criminal disposition. It is the nature of policing. Yet one would never question the operational efficacy or value of the traditional 911 system which happens to cost any municipality an order of magnitude greater than ShotSpotter.
The 911 system is broken for shootings
But even with a comparable disposition rate, acoustic gunshot detection has far more value than 911 when it comes to shootings because of the fact that nearly 90% of gunfire incidents are never called in². The traditional 911 system is effectively broken for our most vulnerable communities when it comes to calls for shots fired. While this is a shocking statistic, it becomes more understandable when thinking about residents in communities plagued by persistent gunfire. People are afraid to call in for fear of retribution, or because they assume someone else will call or they essentially have given up. And while 911 has been around since 1968, there has been no true breakthrough innovation in addressing this particular issue until ShotSpotter.
¹Note: 911 Call for Service Data available to ShotSpotter at the time of this posting included the first 15.5 of 17 months that OIG studied, or over 90% of the period. We have imputed the remaining 6 weeks to have an apples-to-apples comparison and do not believe it impacts any of the overall conclusions of this posting.
Gunshot detection augments 911 and leads to more positive outcomes for the community
Focusing on the percentage of alerts that lead to a police report or criminal disposition does not tell the full story of the value of gunshot detection, just as it doesn’t for the 911 system. It would be similar to judging the scoring prowess of a major league baseball player by looking at batting average only without looking at the absolute stat of Runs Batted In (RBI).
Gunshot detection provides a digital alerting system that augments the traditional 911 system and gives voice to a community that cannot or will not call in when dangerous and criminal gunfire takes place. This critical technology is effectively bridging the gap to enable law enforcement to serve and protect at risk, under-invested in communities suffering from gun violence the same way it would show up in an affluent community when those residents make emergency calls for service.
A clearer picture of what it means to have a 24x7 gunshot monitoring system for virtually all gunfire appears when we look more closely at the absolute number of alerts and calls to 911 that resulted in a police report during the same period and in the same area.
Conclusion: ShotSpotter made first responders aware of over 800 additional gunshot wound (GSW) victims than 911.
Conclusion: ShotSpotter made first responders aware of just under 1,700 more instances of illegal use of a firearm than 911.
Conclusion: ShotSpotter made first responders aware of over 150 additional homicides than 911 so investigators could more quickly capture evidence and interview witnesses.
Overall, ShotSpotter led to three to five times more documented criminal events than 911 for the same period and area. These are just three examples of where ShotSpotter alerts led first responders to do important work to protect and serve the people of Chicago where the 911 system measurably underperformed relative to acoustic gunshot detection.
Next, let’s focus next on the singular value to the community of finding GSW victims due to gunshot detection alerts.
II. Saving Lives and Improving Trauma Care Outcomes
The most important value of ShotSpotter is helping first responders improve the trauma care outcomes and save the lives of gunshot wound victims. Every life is sacred. A shooting that results in a homicide is tragic and carries a high price. It goes far beyond the loss of that life as it means a victim’s friends and families have lost a loved one forever. Some are saved because a ShotSpotter alert made first responders aware of a shooting that they would never have known about because there was no call to 911. Some are saved because with ShotSpotter the first responder arrives faster versus waiting for someone to call 911 and the extra processing time it takes.
But what is the value of a life saved? We have seen that for a 17-month period, gunshot detection sent first responders to crime scenes where there was a GSW 809 additional times than traditional 911 calls. Some portion of the victims thankfully had non-life-threatening injuries, but likely many had a more serious wound that could have become worse the longer it took for help to arrive and apply medical treatment. And some would have died if not immediately taken to the hospital. How do we ascribe value to these latter two very positive outcomes that ShotSpotter enabled? It’s difficult to derive a specific figure, so let’s look at a range of possibilities.
We start by looking at the investment Chicago made in ShotSpotter which was approximately $11 million over the 17-month period of the OIG report. Looking exclusively at Code 041A, the OEMC recorded 1,131 crime scenes where at least one gunshot wound victim was found and potentially saved by ShotSpotter’s swift and precise notification to first responders. This represents a cost of only $3,225 per scene³. We at ShotSpotter believe that this is a small price to pay to have a first responder show up and have a chance to help save the lives of victims of gun violence or prevent injuries from worsening.
The matrix below allows us to assess the range of cost to get first responders in place to potentially make a material difference in the outcome of a victim. The vertical axis represents the percent of dispositions where the first responder intervention made a material difference in the outcome. The range sets forth a minimum 5% positive impact (or 66 victims) across the 1,131 GSW victims, ranging to a maximum of 25% (or 330 victims) who had a materially different outcome due to the fast and precise first responder trauma intervention enabled by the ShotSpotter alert.
³ Allocated Cost Calculation: $11m multiplied by 33% which is the percentage that 041A incident types represent out of the four types examined in this post and then dividing that by the 1,131 041A incident types to get a per crime scene dollar figure.
ShotSpotter Social Value Matrix
Across the horizontal axis is the ShotSpotter allocated cost over the 17-month period. Our calculation brought the cost for these 1,131 incidents of gunshot wound victims to $3,647,317 as noted below, but readers may wish to consider a higher or lower allocation cost proportioned to the 17-month cost of acoustic gunshot detection. The numbers within the matrix are the direct cost of ShotSpotter alerts that made an impactful positive trauma intervention.
The investment in delivering on better trauma care interventions for even a relatively small percent of gunshot wound victims range from $8,842 to $88,417. When viewed through this lens it makes for a compelling case. It is especially compelling, for those victim’s family, friends and community who would readily prioritize Chicago first responders to be made aware of and respond to ALL shootings in the event one of theirs could be one of the 1,000+ victims whose life was saved or prospects improved due to an intervention.
Understanding the Complete Picture
It is clear that only focusing on the percentage of alerts that lead to a police report or criminal disposition does not tell the full story of ShotSpotter’s value. To fully understand value, one must also look at the absolute or nominal number of positive outcomes. Communities that experience persistent gunfire are deserving of an augmented 911 system focused on shootings like ShotSpotter that enables first responders to arrive on the scene faster to save the lives of gunshot wound victims and inform law enforcement of serious crimes that they would never have known about for proper intervention.