Gunfire Trends in Milwaukee, 2017-2023

A review of the Milwaukee Police Department’s call logs indicates that gunfire more than doubled during the pandemic in much of the city. At the same time, the likelihood any given gunfire incident was accompanied by a 911 call reporting “shots fired” declined on the north side, but not the south side. Data from the first 5 months of 2023 shows a modest decline in gunfire compared to the height of the pandemic-era violent crime wave, but levels remain much higher than 2019.

The trouble with just measuring reported crime

Milwaukee’s use of ShotSpotter technology provides a unique opportunity to measure a specific kind of crime in a way that doesn’t entirely depend on crime reports. This is helpful because the likelihood that a given crime is reported to the police varies by time and place.

During the COVID-19 pandemic, violent crime spiked in many American cities. Milwaukee set three annual homicide records in a row. After recording 97 homicides in 2019, the city endured 190 in 2020, 193 in 2021, and 214 in 2022 (according to MPD annual reports). The previous record was 168 in 1991, when the city’s population was about 50,000 more than today.

The summer of 2020 also saw massive protests against police killings of Black Americans, following the murder of George Floyd by officers in Minneapolis. Estimates suggest that between 15 and 26 million adults participated in demonstrations across the country during May and early June, making them the largest in American history.

Local crime trends are almost always measured by counting police reports, but these are, by definition, merely reported crimes. The rate at which actual criminal incidents are reported to the police no doubt varies among communities, by type of crime, and over time. The intense scrutiny of policing during the summer of 2020 may well have altered many Milwaukeeans’ likelihood of contacting the police.

The pandemic crime wave coincided with increased controversy over policing, making the relationship between reported crime and actual crime rates even more uncertain. Still, we do have objective data on both occurrences and reports for one type of crime–gunfire.

ShotSpotter uses a network of acoustical sensors to detect and triangulate the locations of gunshots based on the resulting soundwaves. The system covers only a portion of Milwaukee–one section on the north side and a smaller section on the south side. From a technical perspective ShotSpotter seems fairly accurate. An independent quantitative audit of company-provided data found the system was 97% accurate with about a 0.5% false positive rate.

Politically, ShotSpotter is more controversial. Various national organizations criticize the program as an expensive form of police surveillance with little evidence of actual reductions in violence. On the other hand, many local Milwaukeeans, including community activist Vaun Mayes, Director of the Office of Violence Prevention Ashanti Hamilton, and Chair of the Fire & Police Commission Ed Fallone all expressed at least qualified support for the program in recent interviews with the Shepherd Express.

ShotSpotter trends

Every time the ShotSpotter system reports a gunshot, it is logged into the MPD 911 call log under the code “SHOTSPOTTER.” When a human calls 911 to report gunfire, it likewise is logged with the code “SHOTS FIRED.” Each report includes a timestamp and address.

All call log data is published publicly, but the Milwaukee Police Department only keeps 1 hour of incidents online. I obtained records from local software developer Nick Gartmann, who maintains a public repository of historic MPD call logs. He generously provided data covering December 2016 through May 2023, with a few gaps of missing data. The Milwaukee Police Department refused to tell me the boundaries of the ShotSpotter coverage area, but a public information officer did confirm that the coverage area remained unchanged throughout this period. Using the addresses from the call log, I was able to reconstruct the ShotSpotter service areas as shown below.

Roughly, the north side coverage area stretches from I-43 to about 50th St., between the Menomonee Valley to the south and Capitol Drive to the north. The much smaller south side coverage area stretches from about 9th St. to 27th St., from Greenfield Ave. on the north to somewhat south of Lincoln Ave.

ShotSpotter Coverage Areas

Beginning in the summer of 2020, the ShotSpotter data shows an enormous increase in gunfire on the north side coupled with a large increase on the south side.

The north side coverage area recorded an average of 16.1 shots per day in 2019, increasing to 29.6 in 2020 and 39.2 in 2021. Gunfire ticked down slightly in 2022, to 37.5 per day.

The south side coverage area is much smaller. It saw a daily average of 2.9 ShotSpotter reports in 2019. That increased to 3.8 in 2020 and 4.2 in 2021, before falling back to 3.8 last year.

In the month of May alone, ShotSpotter recorded 25 incidents per day on the north side in 2017, falling to 15 in 2018, and 16 in 2019. That jumped to 31 in 2020 and 46 in 2021, before dipping to 42 in 2022 and 36 in 2023. The pattern on the south side has been generally similar.

bar plot showing average daily ShotSpotter reports for each month, Dec. 2016 - May 2023

In 2023, ShotSpotter incidents through May are slightly down since last year in the north side and slightly up on the south side. Compared to Jan – May of 2019, ShotSpotter reports are still up by 172% on the north side, compared with a 48% increase on the south side.

Average ShotSpotter reports per day in City of Milwaukee coverage areas

yearannualJan – May
north sidesouth sidenorth sidesouth side
201719.33.220.22.9
201814.23.312.23.7
201916.12.913.52.5
202029.63.819.22.5
202139.24.238.24.1
202237.53.838.03.5
2023——36.73.7
Analysis of MPD call logs by John Johnson. Records are missing for some days, so this show the average for available days in each period.

ShotSpotter incidents vs. reports

To get a sense of how often gunshots identified by ShotSpotter also result in a 911 call, I applied the following simple test. I drew a circle with a half mile radius around the ShotSpotter alert location. Then, I checked if a contemporaneous 911 call for “shots fired” had occurred at any point inside that circle. To account for delays in the ShotSpotter upload process, I included any call that occurred within 10 minutes either before or after the ShotSpotter timestamp.

The graph below shows the results in the north and south side coverage areas for the past 7 years.

Only a small fraction of gunshots are reported to the police. Based on this analysis, just 5.1%, or about 3,300 out of 63,900 ShotSpotter reports since 2017 have been accompanied by a 911 call reporting “shots fired” within 10 minutes and half a mile of the identified location.

In 2017, similar shares of ShotSpotter reports resulted in 911 calls on both the north and south side coverage areas. Since then, the trajectories have diverged.

On the north side, the share of shots accompanied with a 911 call has declined every year beginning in 2019. The share of calls being reported has dropped from 5.7% in 2017 to 3.6% in 2023 through May. That’s a decline of more than a third.

On the south side, the share of ShotSpotter reports accompanied with a 911 call hovered between 5.1% and 6.2% throughout 2017-2022. Through May of this year, it has shot up to 7.6%. Through the first 5 months of 2023, gunshots appear to be twice as likely to result in a 911 call in the south side service area than the north side service area. That gap didn’t exist before the pandemic.

bar plot showing proportion of ShotSpotter reports accompanied by a 911 call reporting gunfire, annual statistics for each service area

Implications

This data reinforces the importance of remembering that crime reports are just that–incidents residents actively choose to report to the police. In conversation, I’ve heard from many Milwaukee residents that they rarely report gunfire and property crime to the police, simply because they view it as a pointless and frustrating waste of time. This data analysis indicates that (1) only a very small share of gunfire incidents are ever called in to 911, and (2) that small share has declined even further on the north side of the city, as the frequency of shootings more than doubled during the pandemic.

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Milwaukee Police Chief Asks the Public: “Our Hand Is Out. Meet Us Halfway.”

We’re all in this together. If we want a safer Milwaukee, we need people to come together to trust law enforcement, to build healthy connections in neighborhoods, to provide help to those who might otherwise be headed for trouble. Law enforcement can’t do it alone.

That was the broad message from the Milwaukee area’s two top law enforcement leaders during an “On the Issues” program Thursday, June 1, 2023, at Eckstein Hall.

The most powerful statement of the theme came from Milwaukee Police Chief Jeffrey Norman. Derek Mosley, director of the Law School’s Lubar Center for Public Policy Research and Civic Education and moderator of the program, asked Norman and Milwaukee County Sheriff Denita Ball what they consider the most pressing need of the departments they lead.   

“I’ve said it time and time again: It’s trust. It’s trust that we are doing the right things for the right reasons for you all,” Norman responded, gesturing to the audience of about 200.

Norman, who was named acting chief in 2020 and given the full title in 2021, urged people to leave behind past problems with some of his predecessors. Holding on to the past hampers moving forward, and the department has changed, he said.  

“We have a different culture in the Milwaukee Police Department,” he said. “Believe me. Accountability is real. But we have a lot of great men and women doing work to keep our community safe. And I stand on that.

“It’s important for all of you to know that this is a different department. It’s a different department. Give us that benefit of the doubt. It’s a partnership. It’s not a one-way vehicle here. We can’t get to reckless driving, we can’t get to violent crime, we can’t get to the things that are going on in our neighborhoods if we do not trust each other.

“Our hand is out. Meet us halfway.” He held out his hand as he spoke.

Ball jokingly responded to Norman’s impassioned call by saying, “All right, rev.”

She agreed that trust is important. But she said staffing is the biggest challenge for the sheriff’s department, with need for both more deputies to patrol freeways, parks, and the airport and more people to work in the Milwaukee County Jail, which she oversees.

Norman, who is a 2002 graduate of Marquette Law School, also said staffing is a continuing issue for the police department.

Earlier in the program, Mosley referred to the killings at the Christmas parade in Waukesha in 2021 and at a Fourth of July parade in Highland Park, Ill., in 2022. He asked if tragedies such as those affected preparations for large events in Milwaukee this summer.

Norman said law enforcement plans for what can be done to minimize chances of such crises, including more use of physical barriers, more visible presence of officers, and more work with community groups ahead of and during events. But, he said, events such as the killings in Highland Park by someone who was in a building overlooking the parade can be hard to prevent.

Emphasizing the theme of partnering with the community, he said a big part of what can be done is information and help from citizens. “It’s you all,“ he said. The slogan , “If you see something, say something,” is important, he said. Tips from citizens are valuable.

Ball said the sheriff’s department has built up its relationships with the 19 municipal police departments in Milwaukee County and with other law enforcement agencies. “We are better together,” she said.

Norman said collaboration among agencies was valuable and can increase effectiveness. As he put it, “You’ve got the peanut butter, I’ve got the jelly, let’s make a sandwich.”

The two took several questions and comments from the audience. One person asked how police judge whether to react strongly or stand back when there is major disorder. Norman responded, “I’m not going to allow death and destruction on my watch.”

To watch video of the program, click here.

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Chicago and the Great Lakes Compact

Chicago’s water policy has been a regular subject of conversation at the Law School, whether in the form of public events, faculty scholarship, or blog posts. So, too, has the history and development of the Great Lakes Compact.

Great Lakes from space

Today’s post digs into the unique relationship between the two, given the recent announcement that Chicago has entered into a water supply agreement with the city of Joliet, approximately 35 miles to the southwest. Chicago will supply treated Lake Michigan water to Joliet for a century, beginning in 2030, at a cost estimated to approach $1 billion in today’s dollars. The Cleveland Plain Dealer called the deal a “stark warning” for the Great Lakes Compact. A USA Today column questioned, “How could Chicago [do that]?” The question likely invokes the Compact’s general prohibition on diversions outside the Great Lakes basin, with very limited exceptions. The answer lies in a 1967 amendment to a consent decree involving Illinois and other Great Lakes states, approved by the United States Supreme Court, that largely exempts Chicago from following the Compact’s rules.

The 1967 decree allots to Chicago (and several suburbs, via the Chicago water distribution system) a diversion volume of 3,200 cubic feet per second, or just over two billion gallons per day. The legal disputes that eventually resulted in the decree date back to Chicago’s reversal of the Chicago River, an engineering marvel resulting in no shortage of legal skirmishes. In a case argued before the Supreme Court in 1928 and decided a year later, Wisconsin, Michigan, and New York sued Illinois seeking to enjoin the Chicago diversion—then estimated at 8,500 cubic feet per second—because, they alleged, “the Chicago diversion had lowered the levels of [the Great Lakes and their connecting waterways] not less than six inches, to the serious injury of the complaining states.” The Court ultimately allowed the diversion to continue but capped its size to an amount that varied over decades of subsequent litigation until finally settling on 3,200 cfs in the 1967 decree.

Notably, the Court retains jurisdiction over the decree. From time to time a state has sought to reopen it. In 2010, for example, the Court denied Michigan’s motion to reopen the decree on the grounds that the diversion constituted a public nuisance by allowing the introduction of harmful aquatic invasive species into the Great Lakes.

The Compact’s default approach, a ban on diversions of Great Lakes water outside the Great Lakes basin, would prohibit the Chicago diversion. So there is no doubt that Illinois would not have agreed to the Compact without special carveout provisions protecting its rights to the Chicago diversion under the consent decree. The Compact does just that, in a lengthy section confirming that Great Lakes water use in Illinois is to be governed by the consent decree, not the Compact. In fact, to remove all doubt, the Compact actually prohibits Illinois from applying for diversions under its terms.

The precise terms of the Chicago-Joliet agreement are difficult to find, with the media reporting only the broad outlines of the deal. The Water Supply Agreement attached to the Chicago City Council’s approval provides that “Chicago shall deliver Water to Joliet on any day in an amount as requested by Joliet,” up to a “guaranteed maximum capacity” of 105 million gallons per day. That sounds like a lot of water—and it is—yet even at maximum capacity only accounts for about 0.05% of Chicago’s allocation under the consent decree.

Thus, there is little question that Chicago has the legal authority to sell water to Joliet. And even the maximum delivered volume is a drop in the bucket of Chicago’s allocation under the 1967 consent decree.

Yet the question remains whether it is good policy to sell water for economic development purposes. Some have suggested that as other parts of the country implement water use restrictions, the Great Lakes states should use water as a tool to attract new businesses and residents. Others argue that our abundant water supplies must be carefully stewarded. Finding the right middle ground will be challenging.

As for the Compact, the Joliet sale is perhaps foreboding, as the media coverage has suggested. But its immediate impact is limited to the amount of Chicago’s diversion. Greater difficulties await. At another recent Law School conference, this one commemorating the Compact’s tenth anniversary, former Wisconsin governor Jim Doyle suggested that the Compact’s greatest test would come when a signatory state faced a water crisis in a region outside the Great Lakes basin. Would the governor stick to the Compact and deny water to its own citizens, Doyle wondered? That is exactly the situation unfolding in Illinois, a Great Lakes state that is not governed by the Compact with respect to the Joliet crisis. But the implications for the other Great Lakes states – and the resulting concerns for the future – are unmistakable.

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