Ekonomija ni znanost, ali pač?

Paul Krugman se je malce razkačil nad člankom Rosenberga in Curtaina, da ekonomija ni znanost.

Well, I’m sorry to say that they’ve gotten it almost all wrong. Only “almost”: they’re entirely right that economics isn’t behaving like a science, and economists – macroeconomists, anyway – definitely aren’t behaving like scientists. But they misunderstand the nature of the failure, and for that matter the nature of such successes as we’re having.

Let’s start with the giveaway passage:

An effective chair of the central bank will be one who understands that economics is not yet a science and may never be. At this point it is a craft, to be executed with wisdom, not algorithms, in the design and management of institutions. What made Ben S. Bernanke, the current chairman, successful was his willingness to use methods — like “quantitative easing,” buying bonds to lower long-term interest rates — that demanded a feeling for the economy, one that mere rational-expectations macroeconomics would have denied him.

Whoa! They apparently imagine that QE was an intuitive reaction by Bernanke, one that academic macroeconomics would never have suggested. Nothing could be further from the truth. By the time 2008 came along, the issue of how to conduct monetary policy at the zero lower bound had been extensively discussed, notably in Krugman 1998 (pdf), Eggertsson and Woodford (2003), and, yes, Bernanke-Reinhart-Sack 2004 (pdf). Indeed, the Fed’s QE policies initially followed the latter paper closely; its more recent shift to a greater emphasis on forward guidance is a move in the direction of the Krugman-Eggertsson-Woodford approach.

In other words, far from acting as a free-spirited improviser, Bernanke has been largely implementing recipes developed in the academic literature years before.

So Rosenberg and Curtain completely misunderstand what’s been going on at the Fed. They also misunderstand the nature of economists’ predictive failures. It’s true that few economists predicted the onset of crisis. Once crisis struck, however, basic macroeconomic models did a very good job in key respects — in particular, they did much better than people who relied on their intuitive feelings. The intuitionists — remember, Alan Greenspan was supposed to be famously able to sense the economy’s pulse — insisted that budget deficits would send interest rates soaring, that the expansion of the Fed’s balance sheet would be inflationary, that fiscal austerity would strengthen economies through “confidence”. Meanwhile, wonks who relied on suitably interpreted IS-LM confidently declared that all this intuition, based on experiences in a different environment, would prove wrong — and they were right. From my point of view, these past 5 years have been a triumph for and vindication of economic modeling.

...

Yet obviously something is deeply wrong with economics. While economists using textbook macro models got things mostly and impressively right, many famous economists refused to use those models — in fact, they made it clear in discussion that they didn’t understand points that had been worked out generations ago. Moreover, it’s hard to find any economists who changed their minds when their predictions, say of sharply higher inflation, turned out wrong.

No, the problem lies not in the inherent unsuitability of economics for scientific thinking as in the sociology of the economics profession — a profession that somehow, at least in macro, has ceased rewarding research that produces successful predictions and rewards research that fits preconceptions and uses hard math instead.

Vir: Paul Krugman, New York Times

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