Methodology – Page 10 – artdiamondblog.com

Economics Should Be in “Broad-Exploration Mode”

(p. 85) What does concern me about my discipline, . . . , is that its current core–by which I mainly mean the so-called dynamic stochastic general equilibrium approach–has become so mesmerized with its own internal logic that it has begun to confuse the precision it has achieved about its own world with the precision that it has about the real one. This is dangerous for both methodological and policy reasons. On the methodology front, macroeconomic research has been in “fine-tuning” mode within the local-maximum of the dynamic stochastic general equilibrium world, when we should be in “broad-exploration” mode. We are too far (p. 86) from absolute truth to be so specialized and to make the kind of confident quantitative claims that often emerge from the core. On the policy front, this confused precision creates the illusion that a minor adjustment in the standard policy framework will prevent future crises, and by doing so it leaves us overly exposed to the new and unexpected.
. . .
(p. 100) Going back to our macroeconomic models, we need to spend much more effort in understanding the topology of interactions in real economies. The financial sector and its recent struggles have made this need vividly clear, but this issue is certainly not exclusive to this sector.
The challenges are big, but macroeconomists can no longer continue playing internal games. The alternative of leaving all the important stuff to the “policy”-types (p. 101) and informal commentators cannot be the right approach. I do not have the answer. But I suspect that whatever the solution ultimately is, we will accelerate our convergence to it, and reduce the damage we do along the transition, if we focus on reducing the extent of our pretense-of-knowledge syndrome.

Source:
Caballero, Ricardo J. “Macroeconomics after the Crisis: Time to Deal with the Pretense-of-Knowledge Syndrome.” Journal of Economic Perspectives 24, no. 4 (Fall 2010): 85-102.
(Note: ellipses added.)

Solow Testifies on Irrelevance of DSGE Macro Models

In Nobel-prize-winner Robert Solow’s congressional testimony, quoted below, “DSGE” is an abbreviation for “dynamic stochastic general equilibrium.”

(p. 221) Solow argues: “It may be unusual for the Committee to focus on so abstract a question, but it is certainly natural and urgent. Here we are, still near the bottom of a deep and prolonged recession, with the immediate future uncertain, desperately short of jobs, and the approach to macroeconomics that dominates serious thinking, certainly in our elite universities and in many central banks and other influential policy circles, seems to have absolutely nothing to say about the problem. Not only does it (p. 222) offer no guidance or insight, it really seems to have nothing useful to say. . . . Especially when it comes to matters as important as macroeconomics, a mainstream economist like me insists that every proposition must pass the smell test: does this really make sense? I do not think that the currently popular DSGE models pass the smell test.”

Source:
Taylor, Timothy. “Recommendations for Further Reading.” Journal of Economic Perspectives 24, no. 4 (Fall 2010): 219-26.
(Note: ellipsis in original.)

Debating Grammar: “Think Different” or “Think Differently”

(p. 329) They debated the grammatical issue: If “different” was supposed to modify the verb “think,” it should be an adverb, as in “think dif-(p. 330)ferently.” But Jobs insisted that he wanted “different” to be used as a noun, as in “think victory” or “think beauty.” Also, it echoed colloquial use, as in “think big.” Jobs later explained, “We discussed whether it was correct before we ran it. It’s grammatical, if you think about what we’re trying to say. It’s not think the same, it’s think different. Think a little different, think a lot different, think different. ‘Think differently’ wouldn’t hit the meaning for me.”

Source:
Isaacson, Walter. Steve Jobs. New York: Simon & Schuster, 2011.

Internet Posting May Be Replacing Peer Reviewed Publishing

The article quoted below provides additional signs that institutions of knowledge production and dissemination may be changing in important ways. (Wikipedia is another, even bigger, sign.)

(p. 635) Over the past decade, there has been a decline in the fraction of papers in top economics journals written by economists from the highest-ranked economics departments. This paper documents this fact and uses additional data on publications and citations to assess various potential explanations. Several observations are consistent with the hypothesis that the Internet improves the ability of high-profile authors to disseminate their research without going through the traditional peer-review process.

Source:
Ellison, Glenn. “Is Peer Review in Decline?” Economic Inquiry 49, no. 3 (July 2011): 635-57.

“It Isn’t What You Know that Counts–It Is How Efficiently You Can Refresh”

Source of book image: online version of the WSJ review quoted and cited below.

(p. A17) Knowledge, then, is less a canon than a consensus in a state of constant disruption. Part of the disruption has to do with error and its correction, but another part with simple newness–outright discoveries or new modes of classification and analysis, often enabled by technology.
. . .
In some cases, the facts themselves are variable. . . .
. . .
More commonly, however, changes in scientific facts reflect the way that science is done. Mr. Arbesman describes the “Decline Effect”–the tendency of an original scientific publication to present results that seem far more compelling than those of later studies. Such a tendency has been documented in the medical literature over the past decade by John Ioannidis, a researcher at Stanford, in areas as diverse as HIV therapy, angioplasty and stroke treatment. The cause of the decline may well be a potent combination of random chance (generating an excessively impressive result) and publication bias (leading positive results to get preferentially published).
If shaky claims enter the realm of science too quickly, firmer ones often meet resistance. As Mr. Arbesman notes, scientists struggle to let go of long-held beliefs, something that Daniel Kahneman has described as “theory-induced blindness.” Had the Austrian medical community in the 1840s accepted the controversial conclusions of Dr. Ignaz Semmelweis that physicians were responsible for the spread of childbed fever–and heeded his hand-washing recommendations–a devastating outbreak of the disease might have been averted.
Science, Mr. Arbesman observes, is a “terribly human endeavor.” Knowledge grows but carries with it uncertainty and error; today’s scientific doctrine may become tomorrow’s cautionary tale. What is to be done? The right response, according to Mr. Arbesman, is to embrace change rather than fight it. “Far better than learning facts is learning how to adapt to changing facts,” he says. “Stop memorizing things . . . memories can be outsourced to the cloud.” In other words: In a world of information flux, it isn’t what you know that counts–it is how efficiently you can refresh.

For the full review, see:
DAVID A. SHAYWITZ. “BOOKSHELF; The Scientific Blind Spot.” The Wall Street Journal (Mon., November 19, 2012): A17.
(Note: ellipses added, except for the one internal to the last paragraph, which was in the original.)
(Note: the online version of the article was dated November 18, 2012.)

The book under review, is:
Arbesman, Samuel. The Half-Life of Facts: Why Everything We Know Has an Expiration Date. New York: Current, 2012.

Progress of Economic Science on Central Banking

The passage below is a comment by former head of the Fed, Paul Volcker.

(p. 25) . . . I recently commented to some of my economist friends that I’m not aware of any large contribution that economic science has made to central banking in the last 50 years or so.

Our ability to forecast is still very limited. The old issues of the relative role of fiscal and monetary policies are still debated. Markets are certainly more complex, and some of the old approaches toward monetary control seem less relevant. Recent events have certainly illustrated limitations in our understanding of the economy.
The advent of floating exchange rates, which partly reflects a shift in academic thinking, has certainly been important, but the underlying problems of policy seem familiar.

Stern, Gary H., interviewer. “Paul A.Volcker in Conversation with Gary H. Stern.” The Region (September 2009): 18-29.
(Note: ellipsis added.)

Econometrician Leamer Argues for Methodological Pluralism

(p. 44) Ignorance is a formidable foe, and to have hope of even modest victories, we economists need to use every resource and every weapon we can muster, including thought experiments (theory), and the analysis of data from nonexperiments, accidental experiments, and designed experiments. We should be celebrating the small genuine victories of the economists who use their tools most effectively, and we should dial back our adoration of those who can carry the biggest and brightest and least-understood weapons. We would benefit from some serious humility, and from burning our “Mission Accomplished” banners. It’s never gonna happen.

Source:
Leamer, Edward E. “Tantalus on the Road to Asymptopia.” Journal of Economic Perspectives 24, no. 2 (Spring 2010): 31-46.

Econometric “Priests” Sell Their New “Gimmicks” as the “Latest Euphoria Drug”

The American Economic Association’s Journal of Economic Perspectives published a symposium focused on the thought-provoking views of the distinguished econometrician Edward Leamer.
I quote below some of Leamer’s comments in his own contribution to the symposium.

(p. 31) We economists trudge relentlessly toward Asymptopia, where data are unlimited and estimates are consistent, where the laws of large numbers apply perfectly and where the full intricacies of the economy are completely revealed. But it’s a frustrating journey, since, no matter how far we travel, Asymptopia remains infinitely far
away. Worst of all, when we feel pumped up with our progress, a tectonic shift can occur, like the Panic of 2008, making it seem as though our long journey has left us disappointingly close to the State of Complete Ignorance whence we began.

The pointlessness of much of our daily activity makes us receptive when the Priests of our tribe ring the bells and announce a shortened path to Asymptopia. (Remember the Cowles Foundation offering asymptotic properties of simultaneous equations estimates and structural parameters?) We may listen, but we don’t hear, when the Priests warn that the new direction is only for those with Faith, those with complete belief in the Assumptions of the Path. It often takes years down the Path, but sooner or later, someone articulates the concerns that gnaw away in each of (p. 32) us and asks if the Assumptions are valid. (T. C. Liu (1960) and Christopher Sims (1980) were the ones who proclaimed that the Cowles Emperor had no clothes.) Small seeds of doubt in each of us inevitably turn to despair and we abandon that direction and seek another.
Two of the latest products-to-end-all-suffering are nonparametric estimation and consistent standard errors, which promise results without assumptions, as if we were already in Asymptopia where data are so plentiful that no assumptions are needed. But like procedures that rely explicitly on assumptions, these new methods work well in the circumstances in which explicit or hidden assumptions hold tolerably well and poorly otherwise. By disguising the assumptions on which nonparametric methods and consistent standard errors rely, the purveyors of these methods have made it impossible to have an intelligible conversation about the circumstances in which their gimmicks do not work well and ought not to be used. As for me, I prefer to carry parameters on my journey so I know where I am and where I am going, not travel stoned on the latest euphoria drug.
This is a story of Tantalus, grasping for knowledge that remains always beyond reach. In Greek mythology Tantalus was favored among all mortals by being asked to dine with the gods. But he misbehaved–some say by trying to take divine food back to the mortals, some say by inviting the gods to a dinner for which Tantalus boiled his son and served him as the main dish. Whatever the etiquette faux pas, Tantalus was punished by being immersed up to his neck in water. When he bowed his head to drink, the water drained away, and when he stretched up to eat the fruit hanging above him, wind would blow it out of reach. It would be much healthier for all of us if we could accept our fate, recognize that perfect knowledge will be forever beyond our reach and find happiness with what we have. If we stopped grasping for the apple of Asymptopia, we would discover that our pool of Tantalus is full of small but enjoyable insights and wisdom.

For the full article, see:
Leamer, Edward E. “Tantalus on the Road to Asymptopia.” Journal of Economic Perspectives 24, no. 2 (Spring 2010): 31-46.

Coase: “Firms Never Calculate Marginal Costs”

Source of YouTube video:
http://www.youtube.com/watch?feature=player_embedded&v=ZAq06n79QIs#!

(p. 257) You can watch a 99 year-old Ronald Coase speaking in December 2009 for 25 minutes on the subjects of “Markets, Firms and Property Rights.” “One of the things that people don’t understand is that markets are creations. . . . In fact, it’s very difficult to imagine that firms act in the way that is described in the textbooks, where you maximize profits by equating marginal costs and marginal revenues. One of the reasons one can feel doubtful about this particular way of looking at things is that firms never calculate marginal costs . . . I think we ought to study directly how firms operate and develop our theory accordingly.” From the conference “Markets, Firms and Property Rights: A Celebration of the Research of Ronald Coase,” held at the University of Chicago Law School by the Information Economy Project at George Mason University School of Law. The webpage also includes video of seven panels of prominent speakers, along with PDF files of a dozen or so papers given at the conference. Available at 〈http://iep.gmu.edu/CoaseConference.php〉.

Source:
Taylor, Timothy. “Recommendations for Further Reading.” Journal of Economic Perspectives 24, no. 3 (Summer 2010): 251-58.
(Note: ellipses in original.)

Reality Is Not Always “Elegant”

Source of book image: http://images.betterworldbooks.com/067/Ordinary-Geniuses-Segre-Gino-9780670022762.jpg

(p. C9) In the summer of 1953, while visiting Berkeley, Gamow was shown a copy of the article in Nature where Watson and Crick spelled out some of the genetic implications of their discovery that DNA is structured as a double helix. He immediately realized what was missing. Each helix is a linear sequence of four molecules known as bases. The sequence contains all the information that guides the manufacture of the proteins from which living things are made. Proteins are assembled from 20 different amino acids. What is the code that takes you from the string of bases to the amino acids? Gamow seems to have been the first to look at the problem in quite this way.

But he made a physicist’s mistake: He thought that the code would be “elegant”–that each amino acid would be specified by only one string of bases. (These strings were dubbed “codons.”) He produced a wonderfully clever code in which each codon consisted of three bases. That was the only part that was right. In the actual code sometimes three different codons correspond to the same amino acid, while some codons do not code for an amino acid at all. These irregularities are the results of evolutionary stops and starts, and no amount of cleverness could predict them.

For the full review, see:
JEREMY BERNSTEIN. “The Inelegant Universe.” The Wall Street Journal (Sat., August 13, 2011): C9.

The book under review is:
Segrè, Gino. Ordinary Geniuses: Max Delbruck, George Gamow, and the Origins of Genomics and Big Bang Cosmology. New York: Viking, 2011.