Chicago’s "crime gap"

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One hundred and twenty-one people were killed in Chicago in August of 1991. It was the most violent month in one of the city’s most violent years. “And for every homicide,” the Chicago Tribune reported, “there were 16 other shootings, 10 stabbings, and 19 attacks with clubs or bats.”

Then things got better. Rates of violent crime fell, and not just in Chicago, but all around the country. There were bumps here and there, but the trend was unmistakable—a trend that, in retrospect, has come to be known as the “great crime decline.” It’s a dramatic story of cities getting safer. But it’s an incomplete story.

“In the case of Chicago, between 1991 and 2009 there was a 47 percent decline in homicides,” says Tony Cheng ’12, a doctoral candidate in Yale’s sociology department. But what did this decline look like neighborhood by neighborhood? “Given a world where there are fewer absolute homicides, how evenly are these gains distributed?”

With Andrew Papachristos of Northwestern University and Noli Brazil of the University of California–Davis, Cheng examined changing homicide rates in 342 distinct neighborhoods across Chicago between 1990 and 2010. While all neighborhoods became safer, they found that safety gains were unequally distributed as the gap between the safest and most dangerous neighborhoods grew. In 1991, there were 39 homicides in the most dangerous neighborhoods for every individual homicide in the safest neighborhoods. This ratio grew to 65 to 1 in 2009. The relative “crime gap,” as Cheng and his coauthors describe it, actually increased over time.

“We often hear about the income gap, the education gap, or other types of gaps in society, but I didn’t expect to find as persistent a crime gap, especially given the more general narrative of the crime decline,” says Cheng. Now that the general safety improvements are in place, he adds, policymakers ought to focus on “disentangling at a local level how to spread these safety gains more equally across different neighborhoods.”