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Monday, April 13, 2015

In Defense of Modern Macroeconomic Theory

A small part of a much longer post from David Andolfatto (followed by some comments of my own):

In defense of modern macro theory: The 2008 financial crisis was a traumatic event. Like all social trauma, it invoked a variety of emotional responses, including the natural (if unbecoming) human desire to find someone or something to blame. Some of the blame has been directed at segments of the economic profession. It is the nature of some of these criticisms that I'd like to talk about today. ...
The dynamic general equilibrium (DGE) approach is the dominant methodology in macro today. I think this is so because of its power to organize thinking in a logically consistent manner, its ability to generate reasonable conditional forecasts, as well as its great flexibility--a property that permits economists of all political persuasions to make use of the apparatus. ...

The point I want to make here is not that the DGE approach is the only way to go. I am not saying this at all. In fact, I personally believe in the coexistence of many different methodologies. The science of economics is not settled, after all. The point I am trying to make is that the DGE approach is not insensible (despite the claims of many critics who, I think, are sometimes driven by non-scientific concerns). ...

Once again (lest I be misunderstood, which I'm afraid seems unavoidable these days) I am not claiming that DGE is the be-all and end-all of macroeconomic theory. There is still a lot we do not know and I think it would be a good thing to draw on the insights offered by alternative approaches. I do not, however, buy into the accusation that there "too much math" in modern theory. Math is just a language. Most people do not understand this language and so they have a natural distrust of arguments written in it. .... Before criticizing, either learn the language or appeal to reliable translations...

As for the teaching of macroeconomics, if the crisis has led more professors to pay more attention to financial market frictions, then this is a welcome development. I also fall in the camp that stresses the desirability of teaching more economic history and placing greater emphasis on matching theory with data. ... Thus, one could reasonably expect a curriculum to be modified to include more history, history of thought, heterodox approaches, etc. But this is a far cry from calling for the abandonment of DGE theory. Do not blame the tools for how they were (or were not) used.

I've said a lot of what David says about modern macroeconomic models at one time or another in the past, for example it's not the tools of macroeconomics, it's how they are used. But I do think he leaves out one important factor, the need to ask the right question (and why we didn't prior to the crisis). This is from August, 2009:

In The Economist, Robert Lucas responds to recent criticism of macroeconomics ("In Defense of the Dismal Science"). Here's my entry at Free Exchange in response to his essay:

Lucas roundtable: Ask the right questions, by Mark Thoma: In his essay, Robert Lucas defends macroeconomics against the charge that it is "valueless, even harmful", and that the tools economists use are "spectacularly useless".

I agree that the analytical tools economists use are not the problem. We cannot fully understand how the economy works without employing models of some sort, and we cannot build coherent models without using analytic tools such as mathematics. Some of these tools are very complex, but there is nothing wrong with sophistication so long as sophistication itself does not become the main goal, and sophistication is not used as a barrier to entry into the theorist's club rather than an analytical device to understand the world.

But all the tools in the world are useless if we lack the imagination needed to build the right models. We ... have to ask the right questions before we can build the right models.

The problem wasn't the tools that macroeconomists use, it was the questions that we asked. The major debates in macroeconomics had nothing to do with the possibility of bubbles causing a financial system meltdown. That's not to say that there weren't models here and there that touched upon these questions, but the main focus of macroeconomic research was elsewhere. ...

The interesting question to me, then, is why we failed to ask the right questions. ...

Why did we, for the most part, fail to ask the right questions? Was it lack of imagination, was it the sociology within the profession, the concentration of power over what research gets highlighted, the inadequacy of the tools we brought to the problem, the fact that nobody will ever be able to predict these types of events, or something else?

It wasn't the tools, and it wasn't lack of imagination. As Brad DeLong points out, the voices were there—he points to Michael Mussa for one—but those voices were not heard. Nobody listened even though some people did see it coming. So I am more inclined to cite the sociology within the profession or the concentration of power as the main factors that caused us to dismiss these voices. ...

I don't know for sure the extent to which the ability of a small number of people in the field to control the academic discourse led to a concentration of power that stood in the way of alternative lines of investigation, or the extent to which the ideology that markets prices always tend to move toward their long-run equilibrium values caused us to ignore voices that foresaw the developing bubble and coming crisis. But something caused most of us to ask the wrong questions, and to dismiss the people who got it right, and I think one of our first orders of business is to understand how and why that happened.

Here's an interesting quote from Thomas Sargent along the same lines:

The criticism of real business cycle models and their close cousins, the so-called New Keynesian models, is misdirected and reflects a misunderstanding of the purpose for which those models were devised.6 These models were designed to describe aggregate economic fluctuations during normal times when markets can bring borrowers and lenders together in orderly ways, not during financial crises and market breakdowns.

Which to me is another way of saying we didn't foresee the need to ask questions (and build models) that would be useful in a financial crisis -- we were focused on models that would explain "normal times" (which is connected to the fact that we thought the Great Moderation would continue due to arrogance on behalf of economists leading to the belief that modern policy tools, particularly from the Fed, would prevent major meltdowns, financial or otherwise). That is happening now, so we'll be much more prepared if history repeats itself, but I have to wonder what other questions we should be asking, but aren't.

Let me add one more thing (a few excerpts from a post in 2010) about the sociology within economics:

I want to follow up on the post highlighting attempts to attack the messengers -- attempts to discredit Brad DeLong and Paul Krugman on macroeconomic policy in particular -- rather than engage academically with the message they are delivering (Krugman's response). ...
One of the objections often raised is that Krugman and DeLong are not, strictly speaking, macroeconomists. But if Krugman, DeLong, and others are expressing the theoretical and empirical results concerning macroeconomic policy accurately, does it really matter if we can strictly classify them as macroeconomists? Why is that important except as an attempt to discredit the message they are delivering? ... Attacking people rather than discussing ideas avoids even engaging on the issues. And when it comes to the ideas -- here I am talking most about fiscal policy -- as I've already noted in the previous post, the types of policies Krugman, DeLong, and others have advocated (and I should include myself as well) can be fully supported using modern macroeconomic models. ...
So, in answer to those who objected to my defending modern macro, you are partly right. I do think the tools and techniques macroeconomists use have value, and that the standard macro model in use today represents progress. But I also think the standard macro model used for policy analysis, the New Keynesian model, is unsatisfactory in many ways and I'm not sure it can be fixed. Maybe it can, but that's not at all clear to me. In any case, in my opinion the people who have strong, knee-jerk reactions whenever someone challenges the standard model in use today are the ones standing in the way of progress. It's fine to respond academically, a contest between the old and the new is exactly what we need to have, but the debate needs to be over ideas rather than an attack on the people issuing the challenges.

    Posted by on Monday, April 13, 2015 at 07:13 AM in Economics, Macroeconomics, Methodology | Permalink  Comments (67)


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