PHILADELPHIA — Mortgage delinquencies and foreclosures maintain a high profile as the economy feels its way through a mostly jobless recovery. The home-building business continues to struggle, with several U.S. companies in bankruptcy.

Yet some observers believe they are seeing the emerging signs of a housing shortage. The current overabundance of available homes may be masking a need for more housing in certain parts of the country in the next few years, these analysts say.

Predicting how much housing is needed involves a complex calculus that weighs hard statistics (new-home starts, sales of previously owned homes) against a certain amount of demographic tea-leaf reading (household-formation forecasts). Thus, there isn't complete consensus on what will be enough.

"At current levels of housing construction and demand, the nation has just about two years' worth of excess vacant homes for sale and rent," said Moody's Economy.com chief economist Mark Zandi.

"However, by mid-2012, the market could very well begin to become undersupplied. Construction will likely not have fully caught up to improved demand, and the market will tighten," Zandi said, though it will take longer to work off oversupplies in some states than in others.

Economist Joel Naroff, based in Holland, Pa., isn't so sure.

"While there may be some areas where there could be a modest shortage, that is not likely to be the case here or in most regions," Naroff said. "There was excessive construction during the boom. That has to be taken up first."

Starts ball rolling

Brian Wesbury, chief economist at First Trust Advisors in Wheaton, Ill., started the ball rolling recently when he told Forbes magazine that low housing-construction levels over the last few years meant "we're starting one-third of the houses we need just to keep up with population growth," and that it could create a shortage by 2011.

David Berson, chief economist for PMI Group in Walnut Creek, Calif., said Wesbury was "correct in spirit, even if he goes too far. I don't think we'll face actual shortages, but the current excess supply will end within a couple of years."

To keep pace

Research from the National Association of Realtors shows the U.S. needs to build 1.3 million to 1.7 million housing units annually to keep pace with yearly household formations averaging 1 million to 1.4 million, in addition to replacing the 300,000 obsolete dwellings that are razed each year.

Statistics released two weeks ago by Freddie Mac, however, show that only 910,000 units were started in 2008 and 550,000 in 2009. Projected starts for 2010 are better, but just 700,000 units.

The context for those numbers includes the following:

• At the current sales pace nationwide, the supply of previously owned houses would take 7.8 months to exhaust, not including the vast "shadow market" (houses whose owners are waiting to sell until real estate recovers) and "distressed properties" (foreclosures and bank repossessions).

• The inventory of unsold new houses is at 9.1 months of supply, and the volume for sale is flat at 234,000 homes — a 30-year low.

• At the end of the fourth quarter, 24 percent of all U.S. homes with a mortgage were worth less than the loan balance. The housing vacancy rate in the fourth quarter was 2.7 percent.

• The U.S. homeownership rate is 67.2 percent, down from its peak of 69.2 percent in fourth-quarter 2004 and decimated by record foreclosures.

New Jersey builder Bruce Paparone said a housing shortage is imminent. "People who have put off the buying decision ... will be coming back into the market after waiting for at least four years," he said.

Shortage questioned

But to Rick Sharga, chief economist for foreclosure-tracker RealtyTrac, a shortage is "hard to fathom."

"At the moment, municipalities are bulldozing vacant properties, and there are thousands of partly finished homes dotting the landscape," he said, especially in high-foreclosure states such as Nevada and Arizona.

A shortage is "theoretically possible," Sharga said, if household formations accelerate faster than the housing industry can supply houses.

Lately, the opposite has been true, though, said IHS Global Insight housing economist Patrick Newport. Between March 2008 and March 2009, he said, there were 398,000 household formations, the second lowest since 1947.

That decline explains the housing glut, "despite the sharp contraction in housing starts" since 2006, Newport said. A strong economic recovery — for example, one with jobs that enable young people now living with their parents or in-laws to move out on their own — could help reverse that.

Bank-owned properties

Clogging the U.S. housing pipeline right now, RealtyTrac data show, are about 900,000 bank-owned properties, about 30 percent of which are for sale. Add 1.1 million homes in foreclosure, only 20 percent of which are currently on the market.

Those properties compete with newly built homes. Even if builders limited annual output to 500,000 or so, there still would be 3.5 million to 4.8 million homes for sale at the same time homeownership levels fall slightly because of stricter lending standards, Sharga said.

Where shortages might, indeed, occur is in the rental market, Crowe said.

A homebuilders' association study shows demand for rental housing will outstrip supply by mid-2011, with increasing shortages through 2014. That's likely to increase rents 8 to 10 percent per year in 2011 and 2012, and by 4 to 7 percent per year through 2015, he said.

Of course, shifts in how people want to live help determine where shortages, if any, develop, said Marshal Granor, of Granor Price Homes in Horsham, Pa.

As travel and energy costs rise and disposal income declines, "there are some who prefer to live in the cities or in transit-oriented communities."

"As with all of life," Granor said, "it depends."