The recent upturn in house prices from April to July (3.6%) is the sharpest change in direction professor Robert Shiller has ever seen.

It could signal a v-shaped recovery in house prices. Or it could be the "mother of all head fakes," as investor Whitney Tilson has described it.

Robert Shiller's recent survey of attitudes about house prices suggests it's probably the latter. The survey also suggests that Americans are still delusional about the long-term trajectory for house prices.

In the survey, Shiller and his partner Karl Case ask Americans what they think home prices will do over the short and long term.

The expectation for long-term price changes hasn't changed much since before the bubble (it's now down to 11% a year appreciation). This outlook is more reasonable now than it was at the peak of the bubble, but it's still extraordinarily optimistic. This suggests that Americans still regard the last couple of years as a freak anomaly--even though house prices are just now hitting the range of "normal" on key price ratios like price-to-rent and price-to-income (see charts below).

The outlook for short-term changes (one year), meanwhile, has changed a lot in the past year. Specifically, it has gone from negative a year ago to 2% this summer. Thus, Americans are expecting a near-term housing recovery--in part, perhaps, because of the recovery from April to July.

Shiller thinks this change suggests that buyers are now trying to time the housing market by getting in at the bottom. This could be contributing to the surge in prices we've seen over the last few months.

It's always possible that Americans are right, that we've passed the bottom and are on the way up. If so, however, this would mean remarkable foresight on the part of the average buyer.

Around major changes in market direction (the peak of the housing bubble, for example), there is widespread agreement about what future prices will do--and this consensus is usually 100% wrong. If the consensus is right this time that we've just passed the bottom, therefore, it will be because the average American has suddenly gotten a lot smarter that usual about what the future holds.

Here's Robert Shiller's conclusion in the NYT:

WHAT should we conclude? Given the abnormality of the economic environment, the sudden turn in the housing market probably reflects a new home-buyer emphasis on market timing. For years, people have been bulls for the long term. The change has been in their short-term thinking. The latest answers suggest that people think the price slide is over, so there is no longer such a good reason to wait to buy. And so they cause an upward blip in prices.

At the moment, it appears that the extreme ups and downs of the housing market have turned many Americans into housing speculators. Many people are still playing a leverage game, watching various economic indicators as well as the state of federal bailout programs — including the $8,000 first-time home-buyer tax credit that is currently scheduled to expire before Dec. 1 — in an effort to time their home-buying decisions. The sudden turn could signal a new housing boom, but is more likely just a sign of a period of higher short-run price volatility.

Read the whole thing >

Here are recent price-to-rent and price-to-income charts from Calculated Risk. Note that prices are just now reaching NORMAL levels. To think that they'll suddenly go shooting upwards from here means thinking that they'll go right back to being overvalued.

(That's not impossible, especially with the government giving away money. But it's not a conservative bet. Click the charts to see bigger originals at Calculated Risk)