Monday, April 29, 2013

How to misunderstand crises... with Rational Expectations

** UPDATE BELOW ** I've just about finished Gary Gorton's excellent book Misunderstanding Financial Crises. I think it's the most convincing book I've read so far that links the mechanisms of the recent crisis to crises in the past. In effect, he argues that the crisis was the direct result of the uncontrolled creation of money by the shadow banking sector, and ultimately took place as a classic bank run, no different from runs in the past, except that this run took place mostly out of public view because it didn't involve ordinary bank deposits. The new kind of money in this bank run was stuff such as repo agreements and commercial paper which played the role of money for financial institutions. In 2007-2008, when lenders lost confidence (for good reason) in the mortgage-backed collateral backing this money, they demanded that money back, and the financial system seized up.

The explanation is convincing and wholly natural. The argument is most convincing because Gorton does a masterful job of placing this bank run in the context of the long history of past runs. And also because Gorton, as an economist, places blame squarely on the economics profession (himself included) for being asleep at the wheel:
Think of economists and bank regulators looking out at the financial landscape prior to the financial crisis. What did they see? They did not see the possibility of a systemic crisis. Nor did they see how capital markets and the banking system had evolved in the last thirty years. They did not know of the existence of new financial instruments or the size of certain money markets. They did not know what "money" had become. They looked from a certain point of view, from a certain paradigm, and missed everything that was important... The blindness is astounding. That economists did not think such a crisis could happen in the United States was an intellectual failure.

It seems to me that there is a certain amount of denial among economists. I have noticed, in talking about the ideas in this book with my economist colleagues, that there is a fairly clear generational divide on this. To younger economists and graduate students, it is obvious that there was an intellectual failure. Some older economists are inclined to hem and haw, resorting to farfetched rebuttals. It is clear that this is a sensitive issue, as like banks no one wants to have to write down the value of their capital.
The book gets rather technical in places talking about the details of day to day financing on Wall St., but all in a way that adds credibility to the main argument.

One other thing of interest. Gorton in a late chapter, when discussing the spectacular failure of the rational expectations paradigm, quotes University of Chicago economist James Heckman, winner of the economics' Nobel Prize (yes, that's not its actual name) in 2000, from an interview he did with John Cassidy in 2010. I hadn't come across the interview before. It's a fascinating read and gives some interesting perspective on varied views held by economists within the Chicago department (Cassidy's words in italics):
What about the rational-expectations hypothesis, the other big theory associated with modern Chicago? How does that stack up now?

I could tell you a story about my friend and colleague Milton Friedman. In the nineteen-seventies, we were sitting in the Ph.D. oral examination of a Chicago economist who has gone on to make his mark in the world. His thesis was on rational expectations. After he’d left, Friedman turned to me and said, “Look, I think it is a good idea, but these guys have taken it way too far.”

It became a kind of tautology that had enormously powerful policy implications, in theory. But the fact is, it didn’t have any empirical content. When Tom Sargent, Lard Hansen, and others tried to test it using cross equation restrictions, and so on, the data rejected the theories. There were a certain section of people that really got carried away. It became quite stifling.

What about Robert Lucas? He came up with a lot of these theories. Does he bear responsibility?

Well, Lucas is a very subtle person, and he is mainly concerned with theory. He doesn’t make a lot of empirical statements. I don’t think Bob got carried away, but some of his disciples did. It often happens. The further down the food chain you go, the more the zealots take over.

What about you? When rational expectations was sweeping economics, what was your reaction to it? I know you are primarily a micro guy, but what did you think?

What struck me was that we knew Keynesian theory was still alive in the banks and on Wall Street. Economists in those areas relied on Keynesian models to make short-run forecasts. It seemed strange to me that they would continue to do this if it had been theoretically proven that these models didn’t work.

What about the efficient-markets hypothesis? Did Chicago economists go too far in promoting that theory, too?

Some did. But there is a lot of diversity here. You can go office to office and get a different view.

[Heckman brought up the memoir of the late Fischer Black, one of the founders of the Black-Scholes option-pricing model, in which he says that financial markets tend to wander around, and don’t stick closely to economics fundamentals.]

[Black] was very close to the markets, and he had a feel for them, and he was very skeptical. And he was a Chicago economist. But there was an element of dogma in support of the efficient-market hypothesis. People like Raghu [Rajan] and Ned Gramlich [a former governor of the Federal Reserve, who died in 2007] were warning something was wrong, and they were ignored. There was sort of a culture of efficient markets—on Wall Street, in Washington, and in parts of academia, including Chicago.

What was the reaction here when the crisis struck?

Everybody was blindsided by the magnitude of what happened. But it wasn’t just here. The whole profession was blindsided. I don’t think Joe Stiglitz was forecasting a collapse in the mortgage market and large-scale banking collapses.

So, today, what survives of the Chicago School? What is left?

I think the tradition of incorporating theory into your economic thinking and confronting it with data—that is still very much alive. It might be in the study of wage inequality, or labor supply responses to taxes, or whatever. And the idea that people respond rationally to incentives is also still central. Nothing has invalidated that—on the contrary.

So, I think the underlying ideas of the Chicago School are still very powerful. The basis of the rocket is still intact. It is what I see as the booster stage—the rational-expectation hypothesis and the vulgar versions of the efficient-markets hypothesis that have run into trouble. They have taken a beating—no doubt about that. I think that what happened is that people got too far away from the data, and confronting ideas with data. That part of the Chicago tradition was neglected, and it was a strong part of the tradition.

When Bob Lucas was writing that the Great Depression was people taking extended vacations—refusing to take available jobs at low wages—there was another Chicago economist, Albert Rees, who was writing in the Chicago Journal saying, No, wait a minute. There is a lot of evidence that this is not true.

Milton Friedman—he was a macro theorist, but he was less driven by theory and by the desire to construct a single overarching theory than by attempting to answer empirical questions. Again, if you read his empirical books they are full of empirical data. That side of his legacy was neglected, I think.

When Friedman died, a couple of years ago, we had a symposium for the alumni devoted to the Friedman legacy. I was talking about the permanent income hypothesis; Lucas was talking about rational expectations. We have some bright alums. One woman got up and said, “Look at the evidence on 401k plans and how people misuse them, or don’t use them. Are you really saying that people look ahead and plan ahead rationally?” And Lucas said, “Yes, that’s what the theory of rational expectations says, and that’s part of Friedman’s legacy.” I said, “No, it isn’t. He was much more empirically minded than that.” People took one part of his legacy and forgot the rest. They moved too far away from the data.

** UPDATE **

On a closely related note, check out between 18:00 and about 20:25 of this video documentary on debt and its primary role in the crisis, link courtesy of Lars Syll. Robert Lucas asserts (around 19:40) that debt just doesn't matter because the level of debt and credit always "cancels out." He seems to think it is strange that anyone could even think that debt should matter, as if he's completely blind to the massive agony and social upheaval ensuing from foreclosures and failed businesses around the US and the world. Lars suggests this is "unbelievable stupidity" and it is certainly unbelievable, but I think maybe it is less stupidity and reflects more a kind of borderline autistic inability to make a distinction between some extremely abstract mathematical model and actual economic reality. In Lucas's models, I suspect that debt and credit do always cancel out. Which is one aspect of what makes those models quite useless for many purposes, and dangerous in the hands of anyone who takes them too seriously.  


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