In the latest issue of Mother Jones, Dashka Slater wonders how gentrification in lower-income and minority neighborhoods affects the people who already live there. On the one hand, having a bunch of middle-class professionals move into the neighborhood can lead to "high housing prices, evictions, and a creeping NIMBY-ism that elbows out social services." But the newcomers can also bring "investment, jobs, and tax revenue to neighborhoods that desperately need them," as well as—sometimes—the "political know-how required to extract money and services from urban bureaucracies." Okay, that's what you'd expect. But this, in particular, was interesting:

A 2005 study by Lance Freeman, a professor of urban planning at Columbia University, found the chances that a poor resident of a gentrifying neighborhood would be forced to move were only 1.5 percent—compared to a 1 percent chance of that same resident being displaced in a nongentrifying neighborhood. This is partly because poor people tend to be transient anyway, and partly because poor neighborhoods tend to have high vacancy rates.

That doesn't seem like the whole story, though. Once a neighborhood starts gentrifying, poorer families from elsewhere are less likely to move to the area, as housing prices go up and there are fewer vacancies. So I'd guess that the 1.5 percent figure doesn't capture everything that's going on. Plus, the families that stay can see their rents (or property taxes) go up. Maybe the inflow of investment and jobs can make up for that pinch, but maybe not. A recent NBER paper offered new research suggesting that, for many low-skill African-Americans, labor market discrimination and weaker employment networks were much bigger problems than the lack of decent jobs nearby. So in many minority-heavy urban cores, the "benefits" of gentrification might not be all that great. Hard to say.

Slater cites a green lining to gentrification—namely, that it's better, from an environmental point of view, for middle-class families to move into urban centers than to flock to low-density suburbs (where, according to one University of Toronto study, they would consume twice as much energy and produce twice as much greenhouse gases). That's true. Admittedly, this isn't a topic I know a ton about. The Wikipedia page on gentrification has a lot of good stuff—including not one, not two, but three different theories on why it happens in the first place. Who knew?