"Yet the stigma persists..."

 On bias among white parents:

A recent study in the journal City & Community based on survey data out of eight metropolitan areas in the U.S. suggests that residents—including, presumably, parents—frequently harbor negative associations with the term “urban” and, by extension, “inner-city” communities and institutions, such as schools. To them these words may connote scenes of educational dysfunction—rows of decrepit classrooms, for example, each stocked with an overworked teacher and a cluster of indignant teens, almost all of them poor students of color.

By contrast, the study pointed to evidence that the term “suburban” tends to elicit images of productivity and well-being among white parents. Of course, these stereotypes that white middle-class parents harbor aren’t simply about population density, but race, with “urban” standing in for predominantly black or Latino. A number of studies have shown that white parents tend to select schools with lower proportions of black students, regardless of school quality.