When researchers finally look at data from mid- and post-recession, says Reardon, "it's not clear what will have happened."
For example, if people in middle-class neighborhoods lose their jobs and income but remain in their homes, that could make the neighborhood more economically diverse. If, however, those people are foreclosed upon or otherwise forced to leave their homes for poorer neighborhoods, that would lead to greater income segregation.
According to a census report released this week, the percentage of Americans who changed residences in 2010 and 2011 hit a record low. One reason for this is that homeowners with negative equity, or who are stuck in houses that will not sell, are not able to move.