If the correlation is real, what could be the cause? The professors say they believe that high homeownership in an area leads to people staying put and commuting farther and farther to jobs, creating cost and congestion for companies and other workers. They speculate that the role of zoning may be important, as communities dominated by homeowners resort to “not in my backyard” efforts that block new businesses that could create jobs. Perhaps the energy sector would be less freewheeling in North Dakota if there were more homeowners.

Homeownership, in economists’ jargon, creates “negative externalities” for the labor market.

In Finland, there was something of a test of the thesis, the professors say. Finland changed its housing laws in the 1990s in ways that discouraged homeownership, putting the changes into effect at different times in different regions. “While homeowners are less likely to experience unemployment,” concluded Jani-Petri Laamanen, an economist at the University of Tampere who analyzed the Finnish housing market, “an increase in the rate of homeownership causes regional unemployment to rise.”

Until the credit crisis, homeownership was generally viewed in the United States as an unquestionably good thing. President George W. Bush, like his predecessors, boasted of a rising homeownership rate in his administration. He summarized the consensus in 2005 when he proclaimed June to be “National Homeownership Month.”

“The spread of ownership and opportunity helps give our citizens a vital stake in the future of America and the chance to realize the great promise of our country,” he wrote. “A home provides children with a safe environment in which to grow and learn. A home is also a tangible asset that provides owners with borrowing power and allows our citizens to build wealth that they can pass on to their children and grandchildren.”

Homeownership, the president concluded, is “a bedrock of the American economy, helping to increase jobs, boost demand for goods and services, and build prosperity.”

The benefits of homeownership were said to go far beyond the obvious ones. A document distributed by the National Association of Realtors pointed to positive externalities. Homeowners’ children were more likely to do well in school and less likely to drop out. They were more likely to be well behaved. Teenage pregnancy rates were lower, and the children of lower-income homeowners were less likely to wind up on welfare as adults than were children of similar renters.

The credit crisis damaged that consensus as millions of homeowners lost their homes. Rather than creating wealth, homes had enabled people to gain cash by refinancing mortgages and live beyond their means until the crisis sent them into bankruptcy. The percentage of Americans owning their own homes is now the lowest since 1995.