The American Dream is in relatively good shape in some communities—like Seattle and Salt Lake—but in comparatively bad shape in other communities—like Atlanta and Baltimore. This means poor kids raised in cities like Seattle and Salt Lake City have a much better chance of moving up in the world, income-wise, than children raised in Atlanta and Baltimore.

This much is clear in the research of Harvard University’s Raj Chetty, who has succeeded in casting a spotlight on the role that geography plays in sustaining or strangling the American Dream in one blockbuster study after another. Chetty’s research, of course, raises a fundamental question: what factors explain why some communities succeed and others fail in generating economic opportunity for poor children in America?

Headlines in prominent media outlets like The New York TimesThe Washington Post, and The Atlantic have fingered factors like “racism,” “poverty,” and “segregation” in explaining why some communities do well and others do poorly in promoting the future economic well-being of the low-income children in their midst. And indeed these factors are key, judging by the work of Chetty and his colleagues.

But these factors don’t tell the whole story, as David Leonhardt at The New York Times recently noted. In discussing Chetty’s newest study, which drills down to explore the effects that individual neighborhoods have on the odds that poor kids make it as adults, Leonhardt listed socioeconomic factors like the ones listed above and then asked his readers to guess which factor he had left off the list. He then went on to write this:

I’ve left off one major item from this list, and I’m curious to see whether you noticed. In fact, I left off the second largest correlation… It is: a neighborhood’s share of single-parent households. All else being equal—income, race, educational outcomes—children who grow up in neighborhoods with fewer two-parent families fare notably worse.

What exactly does the relationship between family structure at the neighborhood level and poor children’s odds of realizing the American Dream look like? By merging economic mobility data from Chetty’s project and Census data on family structure at the neighborhood tract level, here’s what we see:

Read more at the Institute for Family Studies