Lars Syll on Krugman as An Apologetic Defender of Esoteric Mathematization

By Lars P. Syll

Paul Krugman had a post up on his blog a while ago where he argued that “Keynesian” macroeconomics more than anything else “made economics the model-oriented field it has become.” In Krugman’s eyes, Keynes was a “pretty klutzy modeler,” and it was only thanks to Samuelson’s famous 45-degree diagram and Hicks’s IS-LM that things got into place. Although admitting that economists have a tendency to use ”excessive math” and “equate hard math with quality” he still vehemently defends — and always have — the mathematization of economics.

See rest here.

Economists do it with models, again

Updating my blog on Nate Silver's FiveThirtyEight.com model forecasts, I left the story in the aftermath of the RNC when it looked like any Romney bounce was below the expectations built into the model. Prior blog linked here.

The model is now responding to inputs from the DNC period, and is showing substantial gains in President Obama's probability of winning in the Electoral College. His probability as of today's (9/8/12) model update is 79.8%, up 2.5 percentage points since the end of the DNC, up 3.5 percentage points since the beginning of the DNC, up 8.2 percentage points since the end of the RNC, and up 10.5 percentage points since the beginning of the RNC. So the model has been consistently increasing the probability of an Obama win for the last 13 days. This is also a model high since it began in June. The early specific poll returns indicate that the Obama bounce is at or exceeding model expectations.

At an 80.0% probability of winning, Obama's win should be categorized as likely on the scale election forecasters appear to use.

I write these words, of course, with pleasure given my political bias. But also with fascination at the extent to which Nate Silver has gone to build a model which responds to the most important inputs to the eventual election outcome. Econometricians, good ones, rock!

This is a clumsy way to show the model output, but the site does not permit a link to just the graphs afaik. And I wanted to visually document the clear uptrend in Obama's winning probability as of this date.

Early Sunday update: Nate Silver has found faith in his model (it's OK Nate, you have the best model I am aware of): link here.

Election anti-bounce - economists do it with models

A very brief observation on economists, models, and the US presidential race.

Nate Silver, an economist (who successfully escaped the University of Chicago after completing his BA there), and a person who got hooked on econometrics, has the best electoral race forecasting model I am aware of.

During the 2008 race, he forecast the outcome within 0.1%.

His current model (as of 9/1/12) has President Obama's probability of winning at 72.0%. That is an increase of 2.7 percentage points during this last week of the Republican national convention. The Republican anti-bounce? Maybe they needed more of Dirty Harry, er, Clint Eastwood?

More importantly, this lead has been fairly consistent, perhaps slowly widening, since June. Those who call the race close are paying too much attention to the national horse-race polls. There, Obama's current projected lead is 1.8%, which is fairly close. But at this point has little bearing on the forecast outcome.

For the more wonkish of you out there, check out Nate's blog FiveThirtyEight.com here. Essentially, Nate's model is a (Bayesian?) weighted average of poll results and economic indicators. His results last time were impressive. It's the best political forecasting model I am aware of.

Update 9/3/12. Happy Labor Day! Some have suggested, including an anonymous comment here, that I am being too optimistic in interpreting the Silver models' outputs. No, I am interpreting the models' output. If they are trending toward Obama, that is what the model is saying.

So it is incumbent that if the model goes negative, I also report that output. Silver's Now-cast went negative early today, indicating a 3.1 percentage point decline from the intra-RNC peak to 71.0%. Note that level is 0.3 percentage points lower than the model indicated at the beginning of the RNC, so interpretation is sensitive to choice of starting points. Some, including Silver wearing his hyper-conservative hat, say this is evidence of a Romney RNC bounce.

OTOH, the paired Nov. 6 Forecast model, which has an adjustment for relative convention bounce as well as an adjustment for relative economic indicators, indicates a further widening in the probability of an Obama win, to 74.5%, a model high.

So the convention period was, in terms of these two models, a toss-up, or as Silver says a split-decision. No one knows which model is more accurate at this point in time; I simply point out that Silver built the Nov. 6 Forecast model to specifically adjust for relative convention performance. (Don't go too wobbly, Nate Silver). What is clear right now is that Romney has underperformed recent convention performances.

On to Charlotte to continue the saga.

Eclecticism, Complexity and Hypocrisy in Economics



In some of my posts there is an open critique of what I referred to the best in the mainstream, people like Krugman and Brad DeLong (and even Larry Summers), that have been in favor of fiscal stimulus, QE, and against tax cuts for the rich.  The critique is not about the soundness of their policy advice or even about their political views, which are liberal in the American sense of the word.  My trouble is the same that Joan Robinson had with the neoclassical synthesis, that is, that their policy propositions do not follow (logically) from their economic models.

Some people may think that this is just splitting hairs, an irrelevant exercise in taxonomy, to determine who is or is not heterodox. And that would certainly be a complete waste of time and energy. But the problem is that this inconsistency between reasonable policy advice and coherent economic theory is at the heart of the problems with the mainstream, and not just the crazy ones that believe in extreme versions of market efficiency (see for example Lucas’ Milliman Lecture; as I suggested these views could be referred to as the Intelligent Design version of economics. Krugman calls it the Dark Ages of macroeconomics).

As I argued somewhere else (subscription required, or preliminary version free here), there is a symbiotic relation between the best in the mainstream (what David Colander refers to as the cutting edge), that sound reasonable and provide rational policy advise particularly in times of crises, and the hardcore fundamentalists that stick to neoclassical/marginalist principles (despite logical problems). The problem is not a trade off between relevance and coherence in general, as Mark Blaug tried to argue with respect to Sraffians (his point being that Sraffians are rigorous and cannot be relevant for that reason; see the reply by Kurz and Salvadori here).  The trade off is a particular problem for the mainstream (that's why Blaug's argument is preposterous).

Rigorous arguments are NOT detrimental for empirical relevance, and they are essential for coherent policy advice. Part of the problem with the current state of the economics profession, what Alessandro Roncaglia has called the cultural roots of the crisis, is that the reasonable so-called New Keynesians, like Larry Summers and Ben Bernanke, were for deregulation and did not see (or didn’t want to see) the crisis coming. There is no intention to revise the foundations of economic analysis.

The whole argument of the best in the mainstream (and even some heterodox economists) is that conventional models are too simplistic and we need more sophisticated models.  In this view, the problem is the complexity of the real world.  Also, the mainstream is not monolithic, and there are several strands, some better some worse, with a high degree of eclecticism. I find the argument disingenuous, at best.  Sure the real world is complex, but the increase in the number of complex models have served since the 1970s as a way of introducing more realistic and often more relevant policy results while maintaining the respectability of the mainstream defense of the sanctity of market efficiency.  Some of these models are not even compatible among them, and, it is true that the mainstream is fragmented or eclectic.  In this sense, I borrowed the use of the term organized hypocrisy to describe, not the behavior of individual economists per se, but of the profession as a whole.

Organized hypocrisy implies that the mainstream can still maintain that markets are efficient, and that General Equilibrium models are a coherent proof of that (which allows the Tea Party version of the profession to go around and preach Real Business Cycles and Supply Side Trickle Down Voodoo Economics), while at the same time say that there are more sophisticated models, with imperfections, and alternative patterns of behavior, that explain reality.  Hence, whether Krugman and other cutting edge authors understand it or not, they have a role within the mainstream which actually serves to perpetuate their hold on the profession.  They are there to make the mainstream sound reasonable without the need to rethink the foundations of the subject.  Eclecticism is not a good feature of the mainstream, it reflects their lack of coherence and the inability to provide a theory that is both realistic and logically sound.

PS: Eclecticism should not be confused with pluralism. One is the result of incoherence, the other of tolerance with different approaches to economics.  For example, institutionalists take a different starting point than Sraffians, but say relevant and coherent things that add to understanding of the real world.  A pluralistic approach that encompasses some of the contributions of both schools is, therefore, quite reasonable.  The same could be said about other heterodox schools.

It's the model stupid!

Brad DeLong, that together with Krugman has been a force for sanity within the mainstream, arguing for more fiscal expansion, shows why we need heterodox economists.  He says in a recent post:

This is a bad time to be an economist. If you were fresh from the womb and had no past opinions to defend, if you had never said anything notable before, it might be a fine time to be an economist. If you are one of those soap-opera characters who has complete amnesia and no memory of anything that they ever said or did or any intellectual position they took before January 1, 2010, it might be a fine time to be an economist. But for the rest of us--we who are now looking back at our opinions and analytic judgments and statements and pronouncements of the past 15 years and thinking: "how could I ever have been so stupid; how could I have missed so much?"--it is a bad time to be economist?

Four years ago we economists were writing learned papers about the "Great Moderation": about how it looked as though the governing institutions of the world economy had finally learned how to control and moderate if not completely eliminate the business cycle--the epileptic seizures of the economy that leave us with pointlessly high unemployment, pointlessly idle capacity, and pointlessly rusting away machines in spite of there being no fundamental cause for machines to be idle, factories closed, and workers unemployed.

Funny, I know of several economists that suggested that an economy based on debt-led consumption, on the basis of asset bubbles, was not sustainable and that a crisis was coming.  It would be tedious to cite all, and I'm lazy and don't want to find links to their papers, but a limited list of names (do a google search) would include Dean Baker, Jane D'Arista, Jerry Epstein, Jamie Galbraith, Wynne Godley, Thomas Palley, Bob Pollin and Lance Taylor (before hand I'm sorry for any significant omissions).  I knew enough to be sure that it was not sustainable.

But I'm glad that the best in the mainstream admit that it was stupid not to see it coming. I would suggest to him that part of the problem of the inability of the mainstream to see it coming is their theoretical framework.  The consensus macroeconomic model, based on an IS curve, a monetary policy rule, and a Phillips Curve with a natural rate of unemployment, in particular because it assumes that the economy automatically returns to the natural rate, is a flawed basis for understanding the real world.