If you're hoping that home prices will recover as sharply as they fell, forget it, says Robert Shiller, Yale economist and co-developer of the Case-Shiller housing index.

Housing markets simply don't experience the "V-shaped" recoveries that most of the homeowners who Shiller and Karl Case recently surveyed believe, Shiller said in an interview with Yahoo Finance.

"Homeowners are not as optimistic as they used to be, but it's still widely believed that home prices are going to go up quite substantially in the long run," Shiller reports, adding that recovery level expectations are still way too high.

"There are a lot of misconceptions about home prices. People think there's a strong uptrend to them, but my data show there is not," says Shiller.

"If you correct for inflation, U.S. home prices in 1990 were about the same as they were in 1890."

"Optimism is a good thing most times," observes technical analyst and trader Matt Blackman.

"(Given current data) it is certainly too soon to break out the housing bottom party shoes and start buying homes again just yet."

Moreover, Shiller points out that if today's home prices recover sufficiently at a nominal level, on a real basis they may still be dropping for a long time to come.

Even if prices stabilized at this level, some 10 million homeowners would owe more money on their homes than they could get from selling them. That leaves a lot of financial companies with major balance sheet problems.

"Housing is a manufactured item. It can depreciate and (builders) can make more of them," says Shiller.

"The problem is that when people are underwater like this, it affects all their decisions," he says.

"It's difficult for them to move because they can't pay off their mortgage, their confidence is lowered, and they're likely to spend less. Even if home prices go up a little bit, they'll still be in that situation."