How did so many people miss the housing bubble?

Several years before the housing bubble burst, there were a few lonesome voices in the media -- such as Yale's Dr. Robert Shiller and former UCLA Anderson Forecast's Chrisopher Thornberg (now with Beacon Economics) -- insisting that there would be serious consequences to pay for rising home values that had no connection at all to underlying economic fundamentals. In the aftermath comes the obvious question: how did such an important story stay for so long under the radar? Dr. Shiller has an answer, which he provides in the New York Times:

ONE great puzzle about the recent housing bubble is why even most experts didn’t recognize the bubble as it was forming.

The failure to recognize the housing bubble is the core reason for the collapsing house of cards we are seeing in financial markets in the United States and around the world. If people do not see any risk, and see only the prospect of outsized investment returns, they will pursue those returns with disregard for the risks.

Were all these people stupid? It can’t be. We have to consider the possibility that perfectly rational people can get caught up in a bubble. In this connection, it is helpful to refer to an important bit of economic theory about herd behavior.

Three economists, Sushil Bikhchandani, David Hirshleifer and Ivo Welch, in a classic 1992 article, defined what they call “information cascades” that can lead people into serious error. They found that these cascades can affect even perfectly rational people and cause bubblelike phenomena. Why? Ultimately, people sometimes need to rely on the judgment of others, and therein lies the problem. The theory provides a framework for understanding the real estate turbulence we are now observing.

Mr. Bikhchandani and his co-authors present this example: Suppose that a group of individuals must make an important decision, based on useful but incomplete information. Each one of them has received some information relevant to the decision, but the information is incomplete and “noisy” and does not always point to the right conclusion.

Let’s update the example to apply it to the recent bubble: The individuals in the group must each decide whether real estate is a terrific investment and whether to buy some property. Suppose that there is a 60 percent probability that any one person’s information will lead to the right decision.

In other words, that person’s information is useful but not definitive — and not clear enough to make a firm judgment about something as momentous as a market bubble. Perhaps that is how Mr. Greenspan assessed the probability that he could make an accurate judgment about the stock market bubble.

The theory helps explain why he — or anyone trying to verify the existence of a market bubble — may have squelched his own judgment.

The fundamental problem is that the information obtained by any individual — even one as well-placed as the chairman of the Federal Reserve — is bound to be incomplete. If people could somehow hold a national town meeting and share their independent information, they would have the opportunity to see the full weight of the evidence. Any individual errors would be averaged out, and the participants would collectively reach the correct decision.

Of course, such a national town meeting is impossible. Each person makes decisions individually, sequentially, and reveals his decisions through actions — in this case, by entering the housing market and bidding up home prices.

This theory poses a major challenge to the “efficient markets” view of the world, which assumes that investors are like independent-minded voters, relying only on their own information to make decisions. The efficient-markets view holds that the market is wiser than any individual: in aggregate, the market will come to the correct decision. But the theory is flawed because it does not recognize that people must rely on the judgments of others.

NOW, let’s modify the Bikhchandani-Hirshleifer-Welch example again, so that the individuals are no longer purely rational beings. Instead, they are real people, subject to emotional reactions.

Furthermore, these people are being influenced by agencies like the National Association of Realtors, which is conducting a public-relations campaign intended to show that putting money into housing is a reliable way to build wealth. Under these circumstances, it’s easy to understand how even experts could come to believe that housing is a spectacular investment.

It is clear that just such an information cascade helped to create the housing bubble. And it is now possible that a downward cascade will develop — in which rational individuals become excessively pessimistic as they see others bidding down home prices to abnormally low levels.

And if that happens -- look for tremendous buying opportunities. So how do you recognize a decent buying opportunity? When it's (a) cheaper to buy than to rent the same unit (factoring in all carrying costs and allowing for vacant periods); (b) you've got a low vacancy rate for renters among your competitors and an ample pool of qualified renters; and (c) you've got a good location within reasonable distance to drive or take public transit to employment centers, shopping and other services.