Why Are Shootings Deadlier In Some Cities Than Others? We need better data to find out.

Murder is a bad statistic for measuring gun violence, yet almost any discussion of gun violence in the United States requires its use.

Consider the cases of Baltimore and Chicago in 2016 to see why murder can be misleading. Chicago, despite its reputation for violence, last year had roughly 28 murders per 100,000 residents, which ranked eighth-highest among big cities in a FiveThirtyEight analysis of 2016 murder rates. Baltimore, by contrast, had the second-highest murder rate in the country, at 51 per 100,000 people. Because firearms are involved in the vast majority of murders, those statistics might make it sound like gun violence is a far bigger problem in Baltimore than Chicago.

But the opposite is true: Chicago last year had more shootings per capita than Baltimore. It’s just that a smaller share of Chicago’s shooting victims ended up dying.

Shootings are a better measure of gun violence than murders are. There is a lot of randomness in what happens once a bullet leaves a gun — whether someone lives or dies depends heavily on luck. Focusing just on murder leaves out all the people who could have died. And it ignores the life-changing injuries and emotional trauma that often accompany nonfatal shootings.

But gun violence researchers are often forced to focus on murders rather than shootings for one simple reason: better data. Cities are not required by the FBI to track shootings specifically, and many cities choose not to count them. Some big cities that had high murder rates in 2016 — such as St. Louis and Memphis, Tennessee — do not collect shooting victim data. And even cities that do collect and release data on shootings often leave out key details; many, for example, don’t distinguish publicly between fatal and nonfatal shootings.

The uneven data collection leaves a major gap in our understanding of gun violence. Looking at shootings, it turns out, shows that the cities with the worst murder rates do not inherently have the highest rates of gun violence victimization, as measured by shooting victims per capita. Murder rates, therefore, may better serve as a measure of how lethal shootings in a city are than as a measure of that city’s overall level of gun violence.

I was able to collect shooting victim data for 2016 on 17 cities using information that is publicly available and requests to individual police departments. For nine of the 17 cities, I accessed shooting victim counts through publicly available official data sources. Six of the cities provided totals upon request, and data for the final two cities was taken from private citizens who keep running shooting totals.

Below, I’ve laid out the number of 2016 shooting victims for each of the 17 cities, as well as the rate of shooting victims and the murder rate (both per 100,000 residents). As the table makes clear, there is a relationship between shootings and murders — places with more shootings also tend to have more murders — but it is imperfect. Cincinnati, for example, is one of the most violent cities on the list, as measured by shootings, despite having comparatively few murders. Newark is the opposite: a city with more murders than its shooting rate would suggest.

RATE PER 100K RESIDENTS CITY TOTAL SHOOTING VICTIMS SHOOTING VICTIMS MURDER VICTIMS Detroit 1,207 179.3 44.9 Chicago 4,376 160.4 27.9 Baltimore 944 152.0 51.2 New Orleans 588 149.4 44.5 Cincinnati 426 142.7 20.8 Atlanta 585 125.9 23.9 Newark 344 122.0 33.0 Milwaukee 672 111.9 23.3 Philadelphia 1,303 83.1 17.7 Minneapolis 340 82.2 8.9 Louisville 504 74.1 17.2 Nashville 309 47.0 12.5 Charlotte 393 44.8 7.5 Boston 229 34.4 7.1 Los Angeles 1,178 29.7 7.4 San Francisco 228 26.4 6.6 New York 1,182 13.8 3.9 Shooting and murder rates in U.S. cities, 2016 Sources: Law enforcement agencies and media reports

What explains the disconnect? On the most basic level, shooting rates don’t always align with murder rates because shootings are more deadly in some cities than others. I was able to get a breakdown between fatal and nonfatal shootings for 14 of the above 17 cities through a mix of publicly available data, requests to police departments and private citizen tallies. Looking at gun violence like this shows that Baltimore had the highest murder rate among the 14 cities in 2016 because shootings were more lethal there.

2016 SHOOTINGS CITY FATAL NONFATAL FATAL SHARE Baltimore 274 670 29.0% New Orleans 164 424 27.9 Newark 87 257 25.3 Detroit 250 957 20.7 Louisville 102 402 20.2 Nashville 59 250 19.1 Milwaukee 118 554 17.6 San Francisco 39 189 17.1 Philadelphia 219 1,084 16.8 Chicago 713 3,663 16.3 New York 195 987 16.5 Boston 35 194 15.3 Charlotte 49 344 12.5 Cincinnati 52 374 12.2 Shootings are more deadly in some cities Sources: Law enforcement agencies and media reports

Baltimore didn’t just have one bad year. The city’s shootings have been unusually deadly since at least 2011. I collected fatal/nonfatal shooting data for the 14 cities for the last several years and found that the share of shootings that are fatal appears to be relatively stable for each city from year to year. The chart below shows the eight cities with more than 350 shooting victims per year and at least three years’ worth of data. The only city with a clear trend is Milwaukee, where shootings have steadily gotten more deadly since 2011.

Competing explanations

It appears, then, that shootings in Baltimore and New Orleans tend to be more deadly than those in Chicago, contributing to the former two having consistently higher murder rates than Chicago. What isn’t clear is why. Answering this question would provide tremendous insight into the mechanics of gun violence in U.S. cities and could help cities devise strategies for lowering their murder rates. But the question is hard to answer without more complete, more detailed data.

Experts have several theories. One possibility: different guns. Last year, Justin George, a reporter for the Baltimore Sun, looked into why shootings in Baltimore are so lethal. George’s story says that higher-caliber firearms with bigger magazines seem to be replacing older firearms in places like Baltimore and Milwaukee. It’s possible that shootings are more deadly in Baltimore than in Chicago because criminals in Baltimore use more powerful guns or fire more bullets per shooting incident — but testing whether that’s the case isn’t possible with the data currently available.

Different tactics by shooters may also help explain the different levels of lethality among cities. In an interview, George told me that many killings in Baltimore are targeted. He cited a recent incident in which a gunman entered a barbershop and shot a customer waiting for a haircut. “The entire shop was full of customers, but they only hit him,” George said. Surveillance tape shows one of the gunmen return to the shop, he said, to see if the victim was dead.

In Los Angeles, by contrast, shootings tend to be more random. In an interview, John Skaggs, an LA homicide detective who was the protagonist of Jill Leovy’s 2015 book “Ghettoside,” described the typical killing there: “Somebody is driving down the street, they see a potential victim, usually a young black male in gang territory, and that becomes the next victim. That’s your typical gang shooting in LA. From what I’ve read about the East Coast, it’s much more targeted.” (Shootings in Los Angeles do appear to be less lethal than in Baltimore: There were 234 more people shot in Los Angeles than Baltimore last year, but the latter reported 24 more murders.)

Some other experts have speculated that differences in shooting death rates could be tied to differences in emergency medical care: Gunshot victims are more likely to survive if they arrive quickly to a high-quality trauma center. By that logic, however, Baltimore should be one of the least lethal cities in the country. Dr. Sahael Stapleton, a surgeon who previously conducted research at Johns Hopkins Hospital in Baltimore, points out that Baltimore gun violence takes place in relatively concentrated areas near the city’s state-of-the-art trauma center.

Better data

There may be dozens or hundreds of other factors — the placement of ambulances or the amount of street lighting, for example — that may help explain why shootings in certain cities are more lethal than those in others. Without further research, however, it’s impossible to say for sure what drives these differences.

That research won’t be possible until cities begin collecting and making public data on shootings, not just murders. Philadelphia’s shooting victim open data portal is an excellent model. Some cities have begun producing annual reports on homicide or gun violence, which is a good start.

Until more cities follow suit, however, we are left with a mystery that has life or death consequences and little data to help solve it.