A scan of Minnesota skylines confirms that the economy is improving. Building cranes are again a common sight in and near the centers of Minneapolis, St. Paul and other Minnesota cities. But evidence of an improving economy is harder to see at ground level in places where homeless people spend their days and nights. Homelessness remains a visible problem.

Documenting the extent of that problem has been the work of the research arm of the St. Paul-based Wilder Foundation at three-year intervals since 1991. Its latest analysis, based on a count taken on Oct. 25, 2012, was released this week. It confirmed the impression one acquires on Minnesota streets: Homelessness did not decline as the economy improved between 2009 and 2012. To the contrary, it grew by 6 percent.

That's a slower pace of growth than the 25 percent jump that Wilder Research found from 2006 to 2009, when the full force of the recession swept thousands of people out of their homes. But any growth in homelessness since 2009, during what was otherwise a period of recovery, should not sit well with Minnesotans in general and public policymakers in particular. At some point in the last year, 40,000 Minnesotans were homeless, with 14,000 people in such circumstances on a typical night, Wilder projects. About half of the state's homeless people are children under age 17, with the fastest growth in numbers seen among families with young children.

Clearly, recovery has not reached those at the bottom rungs of the economic ladder. Their distress not only depletes their own resources but drains public ones as well. A public policy push to house them would benefit everyone.

Growing homelessness between 2009 and 2012 could be chalked up to the tendency of all recessions to hit the poor first, hardest and longest. But in a blog post, Wilder study directors Greg Owen and Michelle Decker Gerrard suggest that blaming the recession alone for still-growing homelessness is too simplistic. They cite these additional factors behind the increase:

• An insufficient supply of affordable housing. By that, Owen and Gerrard mean housing subsidized by the nonprofit and/or public sectors. The private housing market isn't working for the homeless. The numbers explain: In the Twin Cities, the median monthly income of homeless adults last year was $381, while fair market rent for a one-bedroom apartment was nearly twice as much at $745.

Average waiting time on lists for subsidized housing is one year, with 15 percent of homeless people reporting that when they tried to be placed on a waiting list, they were denied. Since that finding, the federal sequester has further depleted Section 8 housing subsidies, Gerrard said Tuesday. "It might well be worse now," she said.

• More mental and physical disability. Owen and Gerrard report "measurable increases in the level of distress in the population" since Wilder's first count in 1991. One-third of the 2012 homeless adults reported diminished cognitive ability; half said they suffer from a mental or physical disorder. Among those deemed long-term homeless, a whopping 60 percent suffer from mental illnesses.

Improved access to health care, courtesy of the federal Affordable Care Act, could prove to be an important tool to combat homelessness, Gerrard said. That's one more reason to resist GOP efforts to undo Obamacare.

• Inadequate help for homeless youth. About three out of five homeless youth are former residents of foster or group homes. Their transition to independence can be perilous, Owen and Gerrard attest. "Youth on their own have the fewest services available to them," they said, with shelters and other services for homeless adults often ill-suited to the needs of 16-21-year-olds. That's a gap that public policymakers should attempt to fill. The 2013 Legislature provided $4 million in response to an $8 million request from a coalition of nonprofits serving homeless youth. Meeting the rest of that request should have a high priority as an improving economy refills state coffers.

To its credit, the Dayton administration is paying attention. Cathy ten Broeke, state director to prevent and end homelessness, has convened an interagency council to coordinate efforts to tackle the problem. It is expected to develop recommendations in time for the 2014 legislative session.

Ten Broeke notes that Minnesota efforts to end long-term homelessness, particularly among veterans, have produced considerable success. The size of that population has been shrinking in recent years — only to be surpassed by growing numbers of families with children who cannot afford a regular roof over their heads. "What's so striking is the constantly growing divide between incomes decreasing and housing costs rising," she said.

Homelessness isn't just about the economy. But an economy — or a minimum wage — that boosted low-end wages would help.