The Limits of Econometrics

Altho it doesn't explicitly say so, what we're actually talking about in this article is the limits of econometrics. The idea that economic behavior can be predicted with precision and accuracy using mathematic models. In fact, altho a clearly useful tool, uncertainty can and will raise its unpredictable head. The arrogance of delusion is, all too frequently, ready to assume a leadership position.
-Mike
From the New York Times

December 14, 2008

The Way We Live Now

The Remedist

By ROBERT SKIDELSKY

Among the most astonishing statements to be made by any policymaker in recent years was Alan Greenspan’s admission this autumn that the regime of deregulation he oversaw as chairman of the Federal Reserve was based on a “flaw”: he had overestimated the ability of a free market to self-correct and had missed the self-destructive power of deregulated mortgage lending. The “whole intellectual edifice,” he said, “collapsed in the summer of last year.”

What was this “intellectual edifice”? As so often with policymakers, you need to tease out their beliefs from their policies. Greenspan must have believed something like the “efficient-market hypothesis,” which holds that financial markets always price assets correctly. Given that markets are efficient, they would need only the lightest regulation. Government officials who control the money supply have only one task — to keep prices roughly stable.

I don’t suppose that Greenspan actually bought this story literally, since experience of repeated financial crises too obviously contradicted it. It was, after all, only a model. But he must have believed something sufficiently like it to have supported extensive financial deregulation and to have kept interest rates low in the period when the housing bubble was growing. This was the intellectual edifice, of both theory and policy, which has just been blown sky high. As George Soros rightly pointed out, “The salient feature of the current financial crisis is that it was not caused by some external shock like OPEC raising the price of oil. . . . The crisis was generated by the financial system itself.”

This is where the great economist John Maynard Keynes (1883-1946) comes in. Today, Keynes is justly enjoying a comeback. For the same “intellectual edifice” that Greenspan said has now collapsed was what supported the laissez-faire policies Keynes quarreled with in his times. Then, as now, economists believed that all uncertainty could be reduced to measurable risk. So asset prices always reflected fundamentals, and unregulated markets would in general be very stable.

By contrast, Keynes created an economics whose starting point was that not all future events could be reduced to measurable risk. There was a residue of genuine uncertainty, and this made disaster an ever-present possibility, not a once-in-a-lifetime “shock.” Investment was more an act of faith than a scientific calculation of probabilities. And in this fact lay the possibility of huge systemic mistakes.

Read the rest of Skidelsky's article here.