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Friday, February 20, 2009

Pre-Mortems

Not a bad idea:
What allowed some people to see the financial crash coming while so many others missed its gathering force? I put that question recently to Nouriel Roubini, who has come to be known as "Dr. Doom" because of his insistent warnings starting in 2006 that we were heading into a global firestorm.

...First, the standard analytical explanation: Roubini said that he studied a chart in economist Robert J. Shiller's book "Irrational Exuberance." It showed that U.S. housing prices, adjusted for inflation, had remained essentially flat for a century, until the mid-1990s, when they began to shoot up. What's more, Roubini saw that the most recent housing correction in the late 1980s had a severe effect on the financial system -- leading ultimately to the collapse of the savings and loan industry.

So Roubini knew two things: Housing prices wouldn't keep going up forever, and when they went down, they would take a big piece of the financial system with them.

...But everyone else had those same numbers. Why did Roubini act? The answer is that he decided to trust his gut, which told him there was trouble ahead, rather than Wall Street's "wisdom of the crowd," which -- as reflected in stock prices -- said everything was rosy. He concluded that the markets were not pricing in the degree of risk that was actually present in housing.

"The rational man theory of economics has not worked," Roubini said last month at a session of the World Economic Forum at Davos.

...The most compelling rebuttal of the rational model, paradoxically, was delivered by the ultimate rationalist, Alan Greenspan. "I made a mistake in presuming that the self-interests of organizations, specifically banks and others, were such that they were best capable of protecting their own shareholders," the former Fed chairman told Congress last October.

That's why Greenspan didn't see it coming, argues Daniel Kahneman, a Princeton professor who is often described as the father of behavioral economics. His rational-actor model wouldn't let him.

...One of the most powerful ideas I heard at Davos was the idea of "pre-mortem" analysis, which was first proposed by psychologist Gary Klein and has been taken up by Kahneman.

A pre-mortem analysis can provide a real "stress test" to conventional thinking. Let's say that a company or government agency has decided on a plan of action. But before implementing it, the boss asks people to assume that five years from now, the plan has failed -- and then to write a brief explanation of why it didn't work. This approach stands a chance of bringing to the surface problems that the decision makers had overlooked -- the "black swans," to use former trader Nassim Nicholas Taleb's phrase, that people assumed wouldn't happen in the near future because they hadn't occurred in the recent past.

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