[paulajohnson]

Gentrification doesn't reduce segregation, it just moves the boundaries of the segregated areas.

Poor people mostly rent because they can't afford or can't get a mortgage. When an area gentrifies those people are forced out because the rents rise, and wealthy people move in. If you just look at the income distribution in the area it looks like "the population" became wealthier, but if you look at the individuals you find that the old residents have been forced out, and generally wind up poorer because of this (social networks disrupted, work further away etc).