After the LA riots more than twenty years ago Congress created an anti-poverty experiment to find out if placing poor families in better neighborhoods would help them move up the economic ladder. The result: parents and children seemed to benefit little, if at all, from a change in address. But new research now shows nearly the opposite. A large new study has found that geography does indeed have a significant effect on upward mobility and children's likelihood to thrive as adults. David Leonhardt is the managing editor of The Upshot, a news and data project of the New York Times.