My hometown, Chicago, is having a fight over words: in particular, “Chiraq.” That’s a portmanteau of “Chicago” and “Iraq,” which is meant to analogize the city not to that country’s rich cultural heritage, or extreme weather, but to its war. The name seems to have come from a South Side rapper, but has since been popularized by headlines in decidedly non-South Side outlets, at least three different VICE mini-documentaries, and most recently an in-the-works Spike Lee movie.

Most cities might not have a nickname with such staying power, but they’re familiar with the concept. “Killadelphia”; “Murder Worth”; “Bullet Town”; even “Murder Kroger.” Last year, a website called “Judgmental Maps” made a name for itself by posting annotated maps of American cities; some of the entries for Atlanta, to take a city at random, included “Little Crackistan,” “Dangerous Mexicans,” and “Avoid.” The map for Washington, DC, labeled all of the Anacostia area simply “GUNS & AIDS.” Around the same time, an app called SketchFactor announced that it could help you get where you were going while avoiding “sketchy” neighborhoods.

Judging by the debate in Chicago, many people don’t see a problem with these expressions of local reputation. In a widely-shared essay, one prominent writer declared that “Chiraq” was indicative of real problems, from violent crime to concentrated poverty, and “arguing over what to call” that “shameful reality” was simply a tool of distraction—putting up a Potemkin facade to avoid dealing with the real issues.

It’s certainly true that the problems “Chiraq”—and, for that matter, “Killadelphia” or “Bullet Town”—was meant to encapsulate are real. (Even the “Murder Kroger” really did witness a murder.) But the second part of the argument—that the name itself is harmless—is simply not true.

Over the last few years, issues of racial and economic segregation have seen a new burst of attention, covering historic issues like redlining and cutting-edge research on the effect of concentrated poverty on economic mobility. But one of the squishier sides of segregation has received much less coverage: stigma.

Stigma creates the very problems it supposedly reflects

In part, that’s understandable: it’s much harder to measure stigma than it is to measure segregation—or even, as it turns out, to measure intergenerational economic opportunity. But that doesn’t mean it’s not a real, and powerful, force. In fact, strong evidence suggests that stigma can help create the very disadvantages it supposedly reflects.

In his book Great American City: Chicago and the Enduring Neighborhood Effect, the Harvard sociologist Robert Sampson recounts an experiment that involved taking extensive data, including resident surveys, from neighborhoods across Chicago over several years, from roughly 1995 to 2002. One question was whether they could use data collected in 1995 to predict what would happen to neighborhoods over time—including what would happen to their poverty rates.

The results are amazing: a neighborhood’s reputation in 1995 was a stronger predictor of poverty in 2000 than almost any other variable, including the neighborhood’s poverty level in 1995. Put simply, if you want to predict what a neighborhood’s poverty rate will be in a few years, knowing whether that neighborhood has a bad reputation is just as useful as knowing its actual poverty rate today.

But don’t neighborhoods get bad reputations because they already have serious issues? To some extent, yes. But Sampson also found that neighborhoods stigmatized as places where, say, public drinking, fighting, or drug dealing were a major problem were not necessarily the neighborhoods with the highest levels of those activities. Instead, the race and immigrant status of a neighborhood’s residents had a “more powerful” effect on reputation than the actual amount of undesirable behavior.

Reputation as a mechanism of inequality

In other words, much of the popular understanding of how neighborhood reputation works is backwards. Communities acquire a reputation for being “sketchy” to some extent independently of whether or not that “sketchiness” is real—and in a way that’s heavily influenced by racism. Once they have a bad reputation, however, the stigma helps create the very problems it warns others away from—in part by causing people to avoid the neighborhood. In Sampson’s words, “stigmatization” becomes a “self-fulfilling prophecy,” and “shared perceptions of disorder…appear to be a mechanism of durable inequality.”

Nor is Sampson’s work the only evidence pointing towards this conclusion. In a paper published in April of this year, researchers from NYU found that online classified ads from stigmatized neighborhoods received many fewer responses than the exact same ads that described the poster as being from a non-stigmatized neighborhood, suggesting that a neighborhood’s reputation may affect its residents’ economic opportunities. And anecdotally, many city leaders say the same thing. Our colleague Carol Coletta at the Knight Foundation once asked then-Newark Mayor Cory Booker what his greatest challenge was. His replied, “Getting people to believe that things can be different.” He saw a realistic hope that things could get better as an important factor in creating and sustaining positive change.

One part of a system of disadvantage

To be clear, the geography of inequality is not simply an invention of our heads. Very real economic and social systems stretching back generations have led to dramatic and devastating differences in quality of life from one neighborhood to the next in nearly every city in America, and pretending that those inequalities don’t exist would ensure that we don’t do anything to rectify them.

But it is now very clear that the reputations we help create through the way we talk about local inequalities—perceived or actual—have a real, and dangerous, power. At the extreme, I suspect we’ve always know this: presumably even the defenders of “Chiraq” would acknowledge that popularizing a community as “Little Crackistan” could not possibly do anything positive for that neighborhood’s trajectory. But stigma doesn’t need to be so crass to work perniciously. The challenge, then, is to talk about our deeply unequal cities in a way that is tightly tied to the actual facts on the ground, and not racial stereotypes; to describe, without dismissing or caricaturing.

That’s a pretty vague charge, it’s true. But maybe we can start simply by acknowledging that words, and the stigmas they can represent and shape, aren’t harmless.