Econometrics, Calibration, and Fights

Paul Krugman is off on another rant about about dead issues in macroeconomics, in this post and this one, including the usual discussion about “freshwater guys,” who currently exist only in Krugman’s mind.

Several points here:

1. In current macroeconomic thought, calibration methods and econometrics are both widely accepted as useful approaches to answering quantitative questions, and these approaches are often mixed in particular projects. Kydland and Prescott pioneered calibration methods in macroeconomics, and applied them to a particular class of models, but the methods themselves are more general than that, and various Old Keynesians and New Keynesians have found calibration useful.

2. Part of what the calibration people were reacting to, was a view among econometricians that quantitative work was about “testing” theories. The problem is that any macroeconomic model is going to be wrong on some dimensions. To be useful, a model must be simple, and simplification makes it wrong in some sense. Subjected to standard econometric tests, it will be rejected. Models that are rejected by the data can nevertheless be extremely useful. I think that point is now widely recognized, and you won’t find strong objections to it, as you might have in 1982.

3. There was indeed a fight at Minnesota over econometrics. I can’t remember exactly when it happened. Maybe I was working at the Minneapolis Fed at the time. Maybe I wasn’t. In any case, I think I know most of the details of the fight. The people involved were all fine human beings, and if you talked to them at the time about their sides of the argument, they would all make perfect sense. Fights happen among people who work together, and it’s best to let these things rest. I’m sure Krugman could tell us a lot about fights in his own department. This is basically gossip, and is best left for talk in the bar.

4. Krugman tells us:

I’d just add that correspondents tell me that the anti-Keynesians pretty much blockade any hiring of new Keynesians in their departments.

People in academic departments disagree about who to hire. This is news? When an academic hire is made, we think we are making a very long-term commitment, particularly when it’s a tenured appointment. We’re making risky bets on people. Are they intelligent and creative types? Will they be able to adapt when their current research program goes out of fashion? Will they get along well with their colleagues and make everyone more productive? Sometimes things turn out badly. While James Tobin was alive, he wouldn’t tolerate having macroeconomists who were up on contemporary macro in his department. As a result, he set his department back, and they have only recently caught up with where macro has gone. Sometimes things turn out well. In 1991, the University of Minnesota hired Nobu Kiyotaki. Remember that Blanchard and Kiyotaki (1987) was a key innovation in Keynesian economics. The Minnesotans were not doctrinaire about it. They saw a smart and productive guy, hired him, and he went on to do more great things. He now works in the Princeton econ department, with Krugman.