move our economy for everybody. here's what's happened by 1990. the green, wealthy neighborhoods. the purple, the poor neighborhoods. they have taken over a significant portion of middle-class areas. it's very clear what's happening. by 2007 it was even more extreme. particularly when you look at how the wealthy areas have expanded. let's bring in shawn riordan. he's a professor of sociology at stanford university who was one of the authors of this study. mr. riordan, good to have you with us tonight. >> good to be with you, ed. >> what are the consequences of income inequality and segregation in this country? what are we looking at? >> so i think there's a couple consequences we ought to worry about. one is we increasingly live in a