Krugman’s blog, 8/27/13

The Times website was down most of yesterday, but Prof. Krugman did get to make one post, “The Real Trouble With Economics:”

I’m a bit behind the curve in commenting on the Rosenberg-Curtain piece on economics as a non-science. What do I think of their thesis?

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.

Oh, and it would be a real tragedy if the takeaway from recent events becomes that you should listen to impressive-looking guys with good tailors who stroke their chins and sound wise, and ignore the nerds; the nerds have been mostly right, while the Very Serious People have been wrong every step of the way.

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.

Nor is this a new thing. My take on the history of macro is that the notion of equilibrium business cycles had, by the standards of any normal science, definitively failed by any normal scientific standard by 1990 at the latest. The original idea that money had real effects because people were surprised by monetary shocks fell apart in the face of evidence of business cycle persistence; the real business cycle view that nominal shocks didn’t actually matter after all was refuted by decisive evidence (pdf) that, in fact, it did. Yet there was no backing off on this approach. On the contrary, it actually increased its hold on the profession.

So, let’s grant that economics as practiced doesn’t look like a science. But that’s not because the subject is inherently unsuited to the scientific method. Sure, it’s highly imperfect — it’s a complex area, and our understanding is in its early stages. And sure, the economy itself changes over time, so that what was true 75 years ago may not be true today — although what really impresses you if you study macro, in particular, is the continuity, so that Bagehot and Wicksell and Irving Fisher and, of course, Keynes remain quite relevant today.

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.

Why has the sociology of economics gone so wrong? I’m not completely sure — and I’ll reserve my random thoughts for another occasion.

 

About these ads

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Follow

Get every new post delivered to your Inbox.

Join 157 other followers

%d bloggers like this: