Minneapolis and St. Paul have both gentrified considerably over the past 15 years, with rent outpacing income and more wealthy people attracted to the center of Minneapolis and nearby neighborhoods, and blocks along the Green Line in St. Paul.

That’s the conclusion of new research at the University of Minnesota that’s part of a study of gentrification in the Twin Cities that should be completed by next July.

The best data so far is for Minneapolis.

“What we’re calling this phenomenon is the shrinking city,” said Ed Goetz, one of the researchers. “Persons right at the median are now finding fewer places to look at in terms of finding affordable housing.”

The affordability of Minneapolis for homeowners has held up much better than it has for renters, for all races and ethnicities. And the growing gap between income and rent in Minneapolis is most pronounced for Latino and black households, though white families are also getting priced out.

Around the year 2000, a white renter with median income could afford to live in 50 percent of the rentals in every part of Minneapolis. Now several neighborhoods are too expensive to meet even that standard.

Judging census tracts by three accepted indexes of gentrification, the researchers found it most prevalent since 2000 in south Minneapolis along the Blue Line; parts of Northeast; Willard-Hay and Harrison in north Minneapolis, and Hamline/Midway and Frogtown in St. Paul.

For Latinos, the share of neighborhoods with affordable rents shrank to an area mostly confined to near south Minneapolis.

For black households with median renter income, only a few small parts of south and north Minneapolis offered affordable rents. Those places are now gone.

“If you’re African-American, there’s not a single neighborhood in the city where the median renter can afford the median rent,” Goetz said. “The city has disappeared for African-Americans in terms of affordability.”

The researchers are careful to define their terms. Goetz, Tony Damiano and Brittany Lewis judged census tracts by three accepted indexes of gentrification, and found that gentrification has been most prevalent since 2000 in south Minneapolis along the Blue Line; parts of Northeast near downtown and along the river; Willard-Hay and Harrison in north Minneapolis, and Hamline/Midway and Frogtown in St. Paul.

“We think there is good reason to believe that these trends will continue,” Damiano said.

Lewis will start interviewing residents of gentrifying neighborhoods in December to complete the qualitative portion of the research.

She will present her findings in April.

Twitter: @adambelz