Any time an article is written about the overlap of gun violence and politics, there is one response that is guaranteed to be offered: "What about Chicago?" Say that mass shootings have occurred hundreds of times in the last few years and you're asked, "What about Chicago?" Talk about the politics of background check legislation and someone will respond, "What about Chicago?"

Well, let's try to answer that.

Chicago has become a go-to shorthand for opponents of gun-control legislation. That's in part thanks to President Obama calling Chicago home, the fact that the city's mayor is Obama ally Rahm Emanuel and the city's laws aimed at curtailing gun violence -- combined with what often feels like an endless number of shootings. Matt Drudge of the Drudge Report has made the "CHICAGOLAND" sobriquet a staple of his coverage of the city. Breitbart seized on September data for a story about how the city's September was its "deadliest in over a decade." Here's a real-time Twitter search for "Chicago" and "gun control." It's guaranteed to be well-stocked at any given moment.

There's no question that Chicago sees more gun violence than the rest of the country. Using data on mass shootings -- defined here as incidents in which four or more people were shot -- we can compare Chicago to the rest of the country. Since 2013, Chicago has seen 207 people wounded in mass shooting incidents and 32 killed -- far more than any other city. But without robust data on cities of smaller sizes than Chicago, it’s very difficult to know how exceptional Chicago’s per-capita mass shootings are.

(We are looking only at mass shootings for now, for reasons that will become clear later.)


But, of course, Chicago is also bigger than most places. If you look at the number of people injured or killed in these incidents as a function of population, Chicago's tally drops below the median.


The highest ratio of killings to population happened at the Renegade Mountain resort in Tennessee, due to an incident in which four people were killed -- in a place with about 40 permanent residents. Since large-scale shootings in very small places skew the scale, we made two versions of the plotline under the map above. The second shows only cities with rates under 200 shooting victims per 100,000 residents.

Chicago is below the norm when it comes to mass shootings. But the question that's usually asked pertains to shootings overall, and, of course, there have been a lot of shootings in Chicago that weren't mass shootings.

But that's also much harder to compare, due to incomplete data. According to the Chicago Tribune, the number of people shot in Chicago so far this year is at least 2,300 -- or about 84.5 per 100,000 residents. New York City has seen 1,041 so far in 2015 -- 12.3 per 100,000 people. In Detroit last year, there were 1,054 non-fatal shootings and 300 homicides, though it's not clear how many of the homicides were gun-related. If all of the murders were involving firearms, that's 199 incidents for every 100,000 people in 2014. Even excluding the murders, the non-fatal shooting rate was 154.9 incidents for every 100,000 Detroit residents -- double Chicago's rate.

The problem is that many jurisdictions don't release data on shootings overall. Jackson, Miss. -- with one of the highest murders-per-population ratios in 2014 -- doesn't calculate shooting numbers. Neither, to take a city from the other side of the country, does Boise, Idaho. Using data from the Gun Violence Archive, we can estimate that the national rate of shooting injuries and deaths is about 9.47 per capita. Clearly, Chicago is well above that.

Earlier this year, the National Journal published a look at how gun laws in states compare to gun violence rates, finding an inverse correlation -- that is, stricter gun laws were found in states with lower gun violence rates. The libertarian Reason.com noted flaws in the methodology -- such as the inclusion of suicides in some comparisons -- and pointed out that correlation does not mean that those gun laws lowered gun violence rates. That holds true for other research, such as a 2013 study finding lower gun deaths in places with stronger crimes. Are they linked? It's not clear. (Illinois, for what it's worth, fell toward the middle of the 50 states on both gun laws and gun violence in the National Journal's analysis. But, of course, whole states are not comparable to Chicago, either.)

We know that media attention can skew the perception of violence, such as earlier this year when the New York Times noted an uptick in murders in cities. A Washington Post analysis later found that the increase was limited.

In short, it's probably impossible to know how much of an outlier Chicago might be. There are certainly more incidents of gun violence than in many or most cities, but we don't know how many. Detroit appears to have had a worse year in 2014, but lacks the political significance -- and attention -- of Obama's Chicago.

So what about Chicago? We can say that there are a lot of people and a lot of shootings in Chicago. That the rate of gun violence is almost certainly higher than in most cities. And that it will remain a centerpiece of the gun control debate at least until January 20, 2017.