By Matthew Power. A new study on the impacts of gentrification on older, poorer neighborhoods may please infill developers. Popular wisdom has held that as neighborhoods improve, low-income residents are driven out by higher rents and taxes. But at Columbia University, Lance Freeman and Frank Braconi studied housing and vacancies in New York City over several years. They found that in neighborhoods where gentrification was happening, poorer residents were actually 20 percent less likely to move than those in areas not gentrifying. One reason: Rental assistance programs often soften the blow to low-income tenants.