Opinion | What Do We Actually Know About the Economy? (Wonkish) - The New York Times - 0 views
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Among economists more generally, a lot of the criticism seems to amount to the view that macroeconomics is bunk, and that we should stick to microeconomics, which is the real, solid stuff. As I’ll explain in a moment, that’s all wrong
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in an important sense the past decade has been a huge validation for textbook macroeconomics; meanwhile, the exaltation of micro as the only “real” economics both gives microeconomics too much credit and is largely responsible for the ways macroeconomic theory has gone wrong.
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Finally, many outsiders and some insiders have concluded from the crisis that economic theory in general is bunk, that we should take guidance from people immersed in the real world – say, business leaders — and/or concentrate on empirical results and skip the models
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And while empirical evidence is important and we need more of it, the data almost never speak for themselves – a point amply illustrated by recent monetary events.
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chwinger, as I remember the story, was never seen to use a Feynman diagram. But he had a locked room in his house, and the rumor was that that room was where he kept the Feynman diagrams he used in secret.
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What’s the equivalent of Feynman diagrams? Something like IS-LM, which is the simplest model you can write down of how interest rates and output are jointly determined, and is how most practicing macroeconomists actually think about short-run economic fluctuations. It’s also how they talk about macroeconomics to each other. But it’s not what they put in their papers, because the journals demand that your model have “microfoundations.”
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The Bernanke Fed massively expanded the monetary base, by a factor of almost five. There were dire warnings that this would cause inflation and “debase the dollar.” But prices went nowhere, and not much happened to broader monetary aggregates (a result that, weirdly, some economists seemed to find deeply puzzling even though it was exactly what should have been expected.)
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What about fiscal policy? Traditional macro said that at the zero lower bound there would be no crowding out – that deficits wouldn’t drive up interest rates, and that fiscal multipliers would be larger than under normal conditions. The first of these predictions was obviously borne out, as rates stayed low even when deficits were very large. The second prediction is a bit harder to test, for reasons I’ll get into when I talk about the limits of empiricism. But the evidence does indeed suggest large positive multipliers.
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The overall story, then, is one of overwhelming predictive success. Basic, old-fashioned macroeconomics didn’t fail in the crisis – it worked extremely well
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In fact, it’s hard to think of any other example of economic models working this well – making predictions that most non-economists (and some economists) refused to believe, indeed found implausible, but which came true. Where, for example, can you find any comparable successes in microeconomics?
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Meanwhile, the demand that macro become ever more rigorous in the narrow, misguided sense that it look like micro led to useful approaches being locked up in Schwinger’s back room, and in all too many cases forgotten. When the crisis struck, it was amazing how many successful academics turned out not to know things every economist would have known in 1970, and indeed resurrected 1930-vintage fallacies in the belief that they were profound insights.
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mainly I think it reflected the general unwillingness of human beings (a category that includes many though not necessarily all economists) to believe that so many people can be so wrong about something so big.
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. To normal human beings the study of international trade and that of international macroeconomics might sound like pretty much the same thing. In reality, however, the two fields used very different models, had very different intellectual cultures, and tended to look down on each other. Trade people tended to consider international macro people semi-charlatans, doing ad hoc stuff devoid of rigor. International macro people considered trade people boring, obsessed with proving theorems and offering little of real-world use.
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Even before the rise of behavioral economics, any halfway self-aware economist realized that utility maximization – indeed, the very concept of utility — wasn’t a fact about the world; it was more of a thought experiment, whose conclusions should always have been stated in the subjunctive.
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But, you say, we didn’t see the Great Recession coming. Well, what do you mean “we,” white man? OK, what’s true is that few economists realized that there was a huge housing bubble
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True, a model doesn’t have to be perfect to provide hugely important insights. But here’s my question: where are the examples of microeconomic theory providing strong, counterintuitive, successful predictions on the same order as the success of IS-LM macroeconomics after 2008? Maybe there are some, but I can’t come up with any.
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The point is not that micro theory is useless and we should stop doing it. But it doesn’t deserve to be seen as superior to macro modeling.
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And the effort to make macro more and more like micro – to ground everything in rational behavior – has to be seen now as destructive. True, that effort did lead to some strong predictions: e.g., only unanticipated money should affect real output, transitory income changes shouldn’t affect consumer spending, government spending should crowd out private demand, etc. But all of those predictions have turned out to be wrong.
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Kahneman and Tversky and Thaler and so on deserved all the honors they received for helping to document the specific ways in which utility maximization falls short, but even before their work we should never have expected perfect maximization to be a good description of reality.
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But data never speak for themselves, for a couple of reasons. One, which is familiar, is that economists don’t get to do many experiments, and natural experiments are rare
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The other problem is that even when we do get something like natural experiments, they often took place under economic regimes that aren’t relevant to current problems.
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you might be tempted to conclude that the empirical evidence is that monetary expansion is inflationary, indeed roughly one-for-one.
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But the question, as the Fed embarked on quantitative easing, was what effect this would have on an economy at the zero lower bound. And while there were many historical examples of big monetary expansion, examples at the ZLB were much rarer – in fact, basically two: the U.S. in the 1930s and Japan in the early 2000
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These examples told a very different story: that expansion would not, in fact, be inflationary, that it would work out the way it did.
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The point is that empirical evidence can only do certain things. It can certainly prove that your theory is wrong! And it can also make a theory much more persuasive in those cases where the theory makes surprising predictions, which the data bear out. But the data can never absolve you from the necessity of having theories.
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Over this past decade, I’ve watched a number of economists try to argue from authority: I am a famous professor, therefore you should believe what I say. This never ends well. I’ve also seen a lot of nihilism: economists don’t know anything, and we should tear the field down and start over.
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Obviously I differ with both views. Economists haven’t earned the right to be snooty and superior, especially if their reputation comes from the ability to do hard math: hard math has been remarkably little help lately, if ever.
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On the other hand, economists do turn out to know quite a lot: they do have some extremely useful models, usually pretty simple ones, that have stood up well in the face of evidence and events. And they definitely shouldn’t defer to important and/or rich people on polic
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: compare Janet Yellen’s macroeconomic track record with that of the multiple billionaires who warned that Bernanke would debase the dollar. Or take my favorite Business Week headline from 2010: “Krugman or [John] Paulson: Who You Gonna Bet On?” Um.The important thing is to be aware of what we do know, and why.Follow The New York Times Opinion section on Facebook and Twitter (@NYTopinion), and sign up for the Opinion Today newsletter.