I think it would be useful of mathematicians and physicists to look into fresh water macro and express an opinion.

From Robert Waldmann:

"Background on "fresh water" and "salt water" macroeconomics

by Robert

Will Wilkinson asks what’s with the economics profession.

A bit more on the public relations quandary the economics profession ought to be in, if it isn’t already…

When I see DeLong more or less indiscriminately trashing everyone at Chicago, or Krugman trashing Barro, etc., what doesn’t arise in my mind is a sense that some of these guys really know what they’re talking about while some of them are idiots. What arises in my mind is the strong suspicion that economic theory, as it is practiced and taught at the world’s leading institutions, is so far from consensus on certain fundamental questions that it is basically useless for adjudicating many profoundly important debates about economic policy. One implication of this is that it is wrong to extend to economists who advise policymakers, or become policymakers themselves, the respect we rightly extend to the practitioners of mature sciences. There is a reason extremely smart economists are out there playing reputation games instead of trying to settle the matter by doing better science. The reason is that, on the questions that are provoking intramural trashtalk, there is no science.

Sadly, there is no one better to listen to.

Now before going on I note that Wilkinson does not address the merits of DeLong's criticisms or Krugman's. He uses a words to suggest that they are writing unprofessionally but he doesn't present a counter argument to their claims. I have quoted his full post. Nothing on the merits.

Instead he asks if disagreements between economists are so fundamental that there is no professional consensus useful to non economists. My brief answer is “yes.” A longer answer after the jump.

Update: Over at Kling's blog commenter Bill Woolsey hits the nail on the head.

Perhaps part of the problem we face in macroeconomics today is that a substantial part of the "macro" wing of free market economists really think that new classical macroeconomics is "true" because simple and formalistically complete models fit their notion of what is scientific.

After the jump you can read my verbose effort to say that.

By the way, Kling's willingness to criticize the arguments others present to support policy positions with which he agrees is really admirable.


It is like Ricardian equivalence. Because the model people (person) rationally saves to pay future taxes, we are supposed to assume this has a connection to reality?





Arnold Kling has already attempted to explain things to Wilkinson. He obtained a “department of huh?” from Brad DeLong and, for what it’s worth, two extremely intemporate comments from me (one was blocked as suspected spam because I provided to many links to support my claims which suggests something about the intellectual seriousness of comment threads at at least one blog).

While I claim that Kling’s take on the stimulus debate is absolutely inconsistent with facts in the public record which I found with a few minutes of googling, I share his general view on the divisions in the profession. He notes that there is more than one fundamental gulf which means that there isn’t a consensus among economists which would enable the few non economists who respect us to take our advice. I will mention three more just because I want to consider more economists than those discussed by Wilkensen and Kling and not because I think Kling left out anything relevant to his post

Kling discusses the policy advice of macroeconomists (and Fama). Not all economists are macroeconomists who think that it is there job to offer policy advice. He notes two divisioins left and right and fresh water and salt water.

Left and right correspond fairly closely to libertarian vs egalitarian in the US political spectrum, that is, closely to Democratic vs Republican positions on economics (except that there are leading economists well to the left of the Democratic party and well to right of all but the left fringe of the Republican party). It is a fact that, except for general support for free international trade, the range of views of economists is similar to the range of views of congressmen but somewhat broader. This is a wide enough ideological range that the methods of verification used by economists are absolutely unable to force economists on left and right to admit that economists on right and left have a point.

In the field of macroeconomics there is a much deeper division between macroeconomics as practiced at universities closer to the great lakes than to an Ocean (Fresh water economics) and that practiced at universities closer to Oceans (Salt water economics). The geography has shifted some as Fresh water economics has been exported. I’d consider Professor Robert Barro at Harvard to be brackish (with, he reports, noticed salty contamination in the first 6 months after he moved from U. Rochester) and the economics department at the University of Pompeu Fabra (in Barcelona) seems to be distilled. It is a little difficult to explain the disagreement to non economists. Frankly, I think this is because non-economists have difficulty believing that any sane person would take ffresh water economics seriously.

Roughly Fresh water economists consider general equilibrium models with complete markets and symmetric information to be decent approximations to reality. Unless they are specifically studying bounded rationality they assume rational expectations, that everyone knows and has always known every conceivable conditional probability. I’ve only met one economists who claims to believe that people actually do have rational expectations (and I suspect he was joking). However, the fresh water view is that it usually must be assumed that people have rational expectations.

Over near the Great Lakes there is considerable investigation of models in which the market outcome is Pareto efficient, that is, it is asserted that recessions are optimal and that, if they could be prevented, it would be a mistake to prevent them.

Salt water macroeconomics is basically everything else with huge differences between people who attempt to conduct useful empirical research without using formal economic theory and people who note the fundamental theoretical importance of incomplete markets and of asymmetric information and of imperfect competition (as in everything you think you know about general equilibrium theory is known to be false if markets are incomplete or there is asymmetric information or there is imperfect competition – Market outcomes are generically constrained Pareto inefficient which means that everyone can be made better off by regulations imposed by regulators who don’t know anything not known to market participants who also just restrict economic activity and don’t introduce innovations like, say, unemployment insurance).

Leading fresh water macroeconomists include Robert Lucas, Ed Prescott Thomas Sargent, Lars Hansen, John Cochrane, Larry Jones, Robert Barro (mostly), and Kevin Murphy (usually). Leading salt water economists include Paul Samuelson, Edmund Malinvaud, Jacques Dreze, Joseph Stiglitz, Robert Solow, Paul Krugman, Andrei Shliefer, Olivier Blanchard, George Akerlof, Robert Hall, Ben Bernankle, N. Gregory Mankiw, Christina Romer, David Romer and, and Lawrence Summers. Brad DeLong is also a salt water economist and he is very very smart, but last I knew, he was a little too far out there to be really a member of the economists club. I can’t classify Paul Romer.

Notably all of the above have made important contributions to fields other than macroeconomics.

In the US there is a strong correlation between Fresh and Salt and Right and Left. The correlation is not perfect: I understand that Hansen and Sargent are politically left of center. Hall is far right politically, Mankiw is right of center. and I must admit that I have no clue about Bernanke (who I have never actually, you know, seen in the flesh).

An important discrimminant is opinions of John Maynard Keynes. Fresh water macroeconomists generally seem to think that he was not a competent economist. Salt water macroeconomists claim (often implausibly) to be in some way his intellectual followers. Barro for example clearly doesn’t remember what is written in “The General Theory of Employment Interest and Money.” Mankiw, in contrast, advised the students in his macro class (including me) to read it again and again searching for insights.

Interestingly, the fresh water macroeconomists are certain that salt water macro is discredited along the lines of the Ptolomaic model or the Phlogiston hypothesis. For a while they called their models “Modern Business Cycle Theory” stating that all incompatible models were obsolete. In the current debate many have considered it sufficient to say that arguments for the stimulus are nonsense (e.g. Cochrane). The surprisingly low quality of contributions to the debate from the vicinity of Great Lakes has a lot to do with the fact that Fresh Water macroeconomists haven’t thought about fiscal stimulus in decades and sincerely believe that it is an obviously invalid proposal so obvious arguments against it might be valid.

Even more interesting, Fresh water macroeconomists do not claim that their models have not been refuted by the data. Rather they note that all models are, by definition, false. They do test hypotheses from time to time, but don’t explain what the point is. As far as I can understand, they claim that a model *can* be both false and useful and, therefore, their models *are* useful.

I understand that in the 70s and, maybe, the early 80s there was a heated debate between Fresh Water and Salt water macroecnomists. Now, it seems to me that there is a truce of sorts where each school of thought ignores the other – that macroeconomists have specialized not in the questions that they ask but in the answers.

I think that this is a very bad situation. Anyone can see that, when top macroeconomists are asked for policy advice, some support each of the different proposals which are under consideration.

Frankly, this truce seems to me to be unilateral. Many salt water economists claim (in public) to respect the contribution of fresh water economists. I know of no fresh water economist who has expressed anything but contempt for the contributions of salt water economists to the stimulus debate and I haven’t heard one word of praise of a Salt Water economist from a Fresh water macroeconomist other than Arrow, Samuelson or Solow. I added the phrase “in public” because I clearly remember one of the salt water economists on my list refer to the fresh water economists as “the crazies”.

update: The truce is over. There have been continual cease fire offensives violations, but the shrill blitzkreig is here.

As far as I can tell, fresh water economists have some respect for some thinkers other than fresh water economists. I think they have rather a favorable view of mathematicians and Physicists. I think it would be useful of mathematicians and physicists to look into fresh water macro and express an opinion. On the other hand, in principle they have great respect for general equilibrium theory, but they don’t listen to general equilibrium theorists at all. Top general equilibrium theorists are all at least left of center politically, the closest David Cass could come to naming an exception is Ed Prescott who, he said, uses general equilibrium theory and studies examples (snort).

Finally I have a view of how people can devote so much effort to working out the implications of assumptions which almost no ordinary people would find other than nonsensical if they understood them. Fresh water economics uses difficult mathematical tools. Students in fresh water graduate programs have to learn a huge amount of math very fast. It is not possible to do so if one doesn't set aside all doubt as to the validity of the approach. Once the huge investment has been made it is psychologically difficult to decide that it was wasted. Hence the school gets new disciples by forcing students to follow extremely difficult courses. Last I hear very few graduate students at U Minnesota came from the USA. Undergrads over there know what the program is like. If my information is not out of date, innocents from abroad are the new blood of fresh water economics."

Me:

Don the libertarian Democrat says:

Today, 2:40:56 PM

“I believe that there is a difference between Economics and Political Economy. Many FW theorists don't seem to agree with this, while SW ones do. My personal favorite is Alan Blinder. Political Economy necessitates that one cannot rely on math or models. They are of limited use. Some of the FW models are of some use, but they do not decribe laws of nature. At best, they are correlative reasoning dressed up with equations. They describe possible movements among different stats or facts. In our situation, there are good arguments for both trying government spending and tax cuts. While a large stimulus would be nice, we are somewhat constrained by debt. I would probably also use more QE. Wilkinson seems to believe that certainty or agreement is necessary for Economics to be useful. He is wrong. It is useful to Political Economy, which, while not leading to certainty, does lend itself to better and worse arguments.Finally, about science. There is often a lot more disagreement on theories than people believe.

it commits one of the most basic fallacies in economics — interpreting an accounting identity as a behavioral relationship.

From Paul Krugman:

"A Dark Age of macroeconomics (wonkish)

Brad DeLong is upset about the stuff coming out of Chicago these days — and understandably so. First Eugene Fama, now John Cochrane, have made the claim that debt-financed government spending necessarily crowds out an equal amount of private spending, even if the economy is depressed — and they claim this not as an empirical result, not as the prediction of some model, but as the ineluctable implication of an accounting identity.

There has been a tendency, on the part of other economists, to try to provide cover — to claim that Fama and Cochrane said something more sophisticated than they did. But if you read the original essays, there’s no ambiguity — it’s pure Say’s Law, pure “Treasury view”, in each case. Here’s Fama:

The problem is simple: bailouts and stimulus plans are funded by issuing more government debt. (The money must come from somewhere!) The added debt absorbs savings that would otherwise go to private investment. In the end, despite the existence of idle resources, bailouts and stimulus plans do not add to current resources in use. They just move resources from one use to another.

And here’s Cochrane:

First, if money is not going to be printed, it has to come from somewhere. If the government borrows a dollar from you, that is a dollar that you do not spend, or that you do not lend to a company to spend on new investment. Every dollar of increased government spending must correspond to one less dollar of private spending. Jobs created by stimulus spending are offset by jobs lost from the decline in private spending. We can build roads instead of factories, but fiscal stimulus can’t help us to build more of both.1 This is just accounting, and does not need a complex argument about “crowding out.”

Second, investment is “spending” every bit as much as consumption. Fiscal stimulus advocates want money spent on consumption, not saved. They evaluate past stimulus programs by whether people who got stimulus money spent it on consumption goods rather save it. But the economy overall does not care if you buy a car, or if you lend money to a company that buys a forklift.

There’s no ambiguity in either case: both Fama and Cochrane are asserting that desired savings are automatically converted into investment spending, and that any government borrowing must come at the expense of investment — period.

What’s so mind-boggling about this is that it commits one of the most basic fallacies in economics — interpreting an accounting identity as a behavioral relationship. Yes, savings have to equal investment, but that’s not something that mystically takes place, it’s because any discrepancy between desired savings and desired investment causes something to happen that brings the two in line.

It’s like the fact that the capital account and the current account of the balance of payment have to sum to zero: that’s true, but it does not mean that an increase in capital inflows magically translates into a trade deficit, without anything else changing (what John Williamson used to call the doctrine of immaculate transfer). A capital inflow produces a trade deficit by causing the exchange rate to appreciate, the price level to rise, or some other change in the real economy that affects trade flows.

Similarly, after a change in desired savings or investment something happens to make the accounting identity hold. And if interest rates are fixed, what happens is that GDP changes to make S and I equal.

That’s actually the point of one of the ways multiplier analysis is often presented to freshmen. Here’s the diagram:

A case of mistaken identity

In this picture savings plus taxes equal investment plus government spending, the accounting identity that both Fama and Cochrane think vitiates fiscal policy — but it doesn’t. An increase in G doesn’t reduce I one for one, it increases GDP, which leads to higher S and T.

Now, you don’t have to accept this model as a picture of how the world works. But you do have to accept that it shows the fallacy of arguing that the savings-investment identity proves anything about the effectiveness of fiscal policy.

So how is it possible that distinguished professors believe otherwise?

The answer, I think, is that we’re living in a Dark Age of macroeconomics. Remember, what defined the Dark Ages wasn’t the fact that they were primitive — the Bronze Age was primitive, too. What made the Dark Ages dark was the fact that so much knowledge had been lost, that so much known to the Greeks and Romans had been forgotten by the barbarian kingdoms that followed.

And that’s what seems to have happened to macroeconomics in much of the economics profession. The knowledge that S=I doesn’t imply the Treasury view — the general understanding that macroeconomics is more than supply and demand plus the quantity equation — somehow got lost in much of the profession. I’m tempted to go on and say something about being overrun by barbarians in the grip of an obscurantist faith, but I guess I won’t. Oh wait, I guess I just did."

Here's my reply:

I think that many of these deniers actually believe that a stimulus by government spending can influence behavior, but they’re worried that accepting that fact will commit them to a stimulus by government spending. Although their use of equations seems simplistic and mechanistic, so does picking an amount for the stimulus as you do. You make it sound as if we’re changing the oil. As well, I feel that infrastructure spending should be efficient and necessary. Just picking a number makes it sound like we’ll spend a lot of money foolishly.

I agree that a stimulus can effect behavior as we wish. I believe it because my political economy is a lot like Shiller’s. I read that he advocates a massive stimulus. And here’s my problem. I’m with Shiller on the stimulus. In order to work well, it needs to be very large. However, I’m also with Buiter, in believing that this spending carries serious risk for us going forward. Consequently, I end up with a plan much like the administration’s.

I also don’t consider social safety net spending a stimulus. It’s what we should do in order to help our citizens get through this crisis. By calling it a stimulus, I’m not sure if these government spending critics are saying that we shouldn’t spend on the social safety net, or simply that they don’t think that infrastructure spending works as a stimulus. As I said, I do, when it’s very large.

— Don the libertarian Democrat

They thought that budget deficits would stimulate growth under all circumstances, not just those of a deflationary depression.

From Mark Thoma:

"Does Stimulus Stimulate?"

Bruce Bartlett:

Does Stimulus Stimulate?, by Bruce Bartlett, Forbes.com: ...The [Great Depression] didn't really end until both monetary and fiscal policy became expansive with the onset of World War II. At that point, no one worried any more about budget deficits, and the Fed pegged interest rates to ensure that they stayed low, increasing the money supply as necessary to achieve this goal.

It was then and only then that the Great Depression truly ended. As a consequence, economists concluded that an expansive monetary and fiscal policy, which had been advocated by economist John Maynard Keynes throughout the 1930s, was the key to getting out of a depression.

Keynes was right, but many of his followers weren't. They thought that budget deficits would stimulate growth under all circumstances, not just those of a deflationary depression( I AGREE WITH BARTLETT HERE, AS I'VE POSTED. BARRO DOESN'T SEEM TO GET THE NATURE OF A CALLING RUN, ALTHOUGH HE SAYS HE DOES. ). When this medicine was applied inappropriately, as it was in the 1960s and 1970s, the result was inflation.( NOT HERE. NOT YET. )

Economists then concluded that it was a mistake to pursue countercyclical fiscal policy, and the idea of "fine-tuning" became a derogatory term. ...

In the 1980s and 1990s, economists came around to the view that only monetary policy could act quickly enough to reverse or moderate a recession. ... [But...] As we have seen, the Fed could not prevent the greatest financial downturn the world has seen since 1929. This has revived the idea that fiscal policy must be the engine that pulls us out.

Somewhat surprisingly, there has been rather heated opposition to the very principle of fiscal stimulus... We have now had several tests of the Keynesian idea--most recently with last year's $300 tax rebate... According to a new paper by University of Michigan economists Matthew Shapiro and Joel Slemrod, only a third of the money was spent, thus providing very little "bang for the buck."( TRUE )

The failure of rebates has shifted the focus to public works and other direct spending measures as a means of stimulating aggregate spending. A study by Obama administration economists Christina Romer and Jared Bernstein predicts that the stimulus plan being debated in Congress will raise the gross domestic product by $1.57 for every $1 spent.

Such a multiplier effect has been heavily criticized by a number of top economists, including John Taylor of Stanford, Gary Becker and Eugene Fama of the University of Chicago and Greg Mankiw and Robert Barro of Harvard.( I LIKE ALL OF THESE PEOPLE ) The gist of their argument is that the government cannot expand the economy through deficit spending because it has to borrow the funds in the first place, thus displacing other economic activities( THIS IS WRONG ). In the end, the government has simply moved around economic activity without increasing it in the aggregate.( WRONG )

Other reputable economists have criticized this position as being no different from the pre-Keynesian view that helped make the Great Depression so long and deep. Paul Krugman of Princeton, Brad DeLong of the University of California at Berkeley and Mark Thoma of the University of Oregon have been outspoken in their belief that theory and experience show that government spending can expand the economy under conditions such as we are experiencing today( I AGREE WITH THEM IN THIS CASE. ).

I think the critics of an activist fiscal policy are forgetting the essential role of monetary policy as it relates to fiscal policy. As Keynes was very clear about, the whole point of fiscal stimulus is to mobilize monetary policy and inject liquidity into the economy. This is necessary when nominal interest rates get very low, as they are now, because Fed policy becomes impotent. Keynes called this a liquidity trap, and I think there is strong evidence that we are in one right now.( ZIRP )

The problem is that fiscal stimulus needs to be injected right now to counter the liquidity trap. If that were the case, I think we might well get a very high multiplier effect this year( I AGREE ). But if much of the stimulus doesn't come online until next year, when we are likely to be past the worst of the slowdown, then crowding out will greatly diminish the effectiveness of the stimulus, just as the critics argue. ... Thus the argument really boils down to a question of timing. ...( I AGREE COMPLETELY )

For this reason, I think there is a better case for stimulating the economy through tax policy than has been made. Congress can change incentives instantly by, for example, saying that new investments in machinery and equipment made after today would qualify for a 10% Investment Tax Credit...( MY IDEA )

Stimulus based on private investment also has the added virtue of establishing a foundation for future growth, whereas consumption spending( OFTEN ) does not. As economist Hal Varian of the University of California at Berkeley recently put it, "Private investment is what makes possible future increases in production and consumption. Investment tax credits or other subsidies for private sector investment are not as politically appealing as tax cuts for consumers or increases in government expenditure. But if private investment doesn't increase, where will the extra consumption come from in the future?"

I don't agree with all of this, e.g. the "government is always the problem" emphasis in the analysis, and casting the debate as a tradeoff between private investment and private consumption rather than between private sector activity (consumption or investment) and public investment overstates the case for private sector solutions. [These arguments from yesterday apply as well.]

I've never objected to tax cuts being part of the package -- I have also argued that the desire for an immediate impact may necessitate some tax cut components in order to maximize the prospects for a faster recovery. And as tax cuts go, there are far worse choices than an investment tax credit( GOOD. THEN JOIN US. ). But just as there's a limit to the number of public sector projects that are shovel ready, there's also a limit to the number of private sector projects that are ready to go (though the planning stage does involve some spending, just not as much as when the public or private sector investment projects are going full throttle)( YES ). There's also a question about how strong the reaction will be to a tax credit when the economic outlook is so gloomy( TRUE. IT MIGHT ONLY MARGINALLY HELP. BUT WE NEED TO TRY. ), a question that doesn't arise when government is making the investments. So, sure, let's get as much out of the private sector as we can, but we shouldn't rely solely upon the private sector response to a tax credit to turn things around( AGREED ). It's very unlikely to be enough on its own, and it may not provide much help at all, Thus, even with tax credits, the public sector response - government spending in particular - still needs to be aggressive."

I agree. Infrastructure investment also sends a positive message. Oh my God. I actually resorted to talking about how people might behave in the real world. A real benefit of the stimulus in Infrastructure ( I said $100 Billion ) would be emotional. I will spend more money if I FEEL LIKE IT. Crowding out, a purely mechanistic explanation, is a fairly useful model, no more, under normal circumstances. Using math to describe correlations between various economic factors doesn't make you a scientist. All that the math does, or any correlative reasoning, is give you some useful guides to understanding how people might react in various circumstances. Crowding out is NOT a law of nature. Adam Smith understood philosophy, politics, economics, history, etc. What education do many of these economists receive? They have a philosophy of math that is hilarious. Of course, so do many mathematicians and philosophers, so let's not go there.

Let me repeat my plan:
1) $100 Billion on infrastructure, to be built only when benefits exceed the costs.
2) Sales tax cut $200 Billion
3) Investment incentives $100 Billion
4) Social safety net spending is not included in my stimulus. It is simply money that needs to be spent as part of the social contract.