The main innovation of the new paper — part of
the Equality of Opportunity Project, involving multiple researchers — is its focus on children who moved. Doing so allows the economists to ask whether the places themselves actually affect outcomes. The alternative is that, say, Baltimore happens to be home to a large number of children who would struggle no matter where they grew up.
The data suggests otherwise. The easiest way to understand the pattern may be the different effects on siblings, who have so much in common. Younger siblings who moved from a bad area to a better one earned more as adults than their older siblings who were part of the same move. The particular environment of a city really does seem to affect its residents.
The data does not answer the question of whether the factors that distinguish higher-mobility places, like better schools and less economic segregation, are causing the differences — or are themselves knock-on effects of other, underlying causes. “We still need clarity on that,” Mr. Grusky, the Stanford professor, said.
From her perspective, Ms. Hawkins, the Contra Costa resident, said that the mixing of people from different social classes did make a difference.
“It’s all spread out here,” she said. In her old home in San Leandro, Calif., entire neighborhoods had high unemployment and crime, which led some people who did have jobs to flee, causing a downward spiral. “You don’t want to put your kid in harm’s way. That’s just extra stress.”
For all the benefits that moves can bring, they are not a solution to poverty, said people who have seen the new paper as well as the researchers themselves. Finding ways to improve those neighborhoods, for people who cannot or do not want to move, is also important, researchers and policy makers said.
“We can’t walk away from them,” Mr. Castro, the housing secretary, said. “We need a two-pronged approach.”
