Global TMW:
Log In  |  Register          Free Newsletter Subscription
Subscribe

Taking the Measure   



Recent Posts

Recent Comments

Most Commented On

Archives

Blog

Link This | Email this | Blog This | Comments (10)


Should we leave the economy to economists?

October 2, 2008

Should we leave the economy to politicians, financiers, and economists, or might physical scientists have something to contribute to the topic?

In a New York Times column titled “This Economy Does Not Compute,” Mark Buchanan, a theoretical physicist, questions the wisdom of the former group, writing, “A few weeks ago, it seemed the financial crisis wouldn’t spin completely out of control. The government knew what it was doing—at least the economic experts were saying so—and the Treasury had taken a stand against saving failing firms, letting Lehman Brothers file for bankruptcy.” Unfortunately, he adds, the Lehman collapse was quickly followed by “the rescue of the insurance giant A.I.G., the arranged sale of failing banks, and we’ll soon see, in one form or another, the biggest taxpayer bailout of Wall Street in history. It seems clear that no one really knows what is coming next.”

Says Buchanan, author of The Social Atom: Why the Rich Get Richer, Cheaters Get Caught and Your Neighbor Usually Looks Like You, part of the problem is that “economists still try to understand markets by using ideas from traditional economics, especially so-called equilibrium theory. This theory views markets as reflecting a balance of forces and says that market values change only in response to new information.” The problem with that theory, he contends, is that “a classic economic study found that of the 50 largest single-day price movements since World War II, most happened on days when there was no significant news, and that news in general seemed to account for only about a third of the overall variance in stock returns." And a more recent study found that news plays a minor role in stock price jumps. The authors (physicist Jean-Philippe Bouchaud and colleagues) report, “We find that neither idiosyncratic news nor market wide news can explain the frequency and amplitude of price jumps. We find that the volatility patterns around jumps and around news are quite different: jumps are followed by increased volatility, whereas news tend on average to be followed by lower volatility levels.”

The reason for the dissociation of price and information, Buchanan explains, is that markets have internal dynamics: “They’re self-propelling systems driven in large part by what investors believe other investors believe…and traders speak for good reason of the market’s optimism or pessimism.”

To account for such factors, he recommends the use of “agent based” computer models that can simulate market dynamics from the bottom up. The idea, he says, is to populate virtual markets with artificially intelligent agents who represent individuals, banks, hedge funds, regulators, and other players and to study the market behavior that emerges from the actions of the interacting agents.

He cites one such model being developed by a Yale economist, John Geanakoplos, and two physicists, Doyne Farmer and Stefan Thurner, which looks at how of credit levels can influence stability. What they have found, he says (while cautioning that the work remains speculative), is something that is not obvious: “…instability doesn’t grow in the market gradually, but arrives suddenly. Beyond a certain threshold the virtual market abruptly loses its stability in a ‘phase transition’ akin to the way ice abruptly melts into liquid water. Beyond this point, collective financial meltdown becomes effectively certain.”

Buchanan also cites work by the German economist Frank Westerhoff on the idea that levying very small taxes on foreign-exchange transactions might help reduce market volatility. Buchanan writes, “A tax of 0.1 percent of the transaction volume, for example, would deter rapid-fire speculation, while preserving currency exchange linked more directly to productive economic purposes.” The tax, it seems, would serve a negative-feedback function.

He also cites the computer-modeling work of Charles Macal and colleagues at Argonne National Laboratory in simulating the Illinois electricity market and potential effects of deregulation. The simulations, he writes, “were instrumental in exposing several loopholes in early market designs that companies could have exploited to manipulate prices.”

Unfortunately, he writes, economists are slow to adopt computer modeling, with one saying the use of computational models amounts to cheating. Buchanan adds, “This seems decidedly peculiar given that every other branch of science from physics to molecular biology has embraced computational modeling as an invaluable tool for gaining insight into complex systems of many interacting parts, where the links between causes and effect can be tortuously convoluted.”

Indeed. I’d prefer that there be some computational evidence that my share of the $700 billion Wall Street bailout Congress is considering will actually do some good.


For more on this topic see "Computational Economics: 'Dark Liquidity'” on nerdlist.net, which cross-references two recent and related New Scientist articles: "Why economic theory is out of whack" (by Mark Buchanan) and "Algorithms battle to trade stocks in the dark."


Posted by Rick Nelson on October 2, 2008 | Comments (10)


Email
Learn RSS


October 2, 2008
In response to: Should we leave the economy to economists?
Ralph commented:

So socialism has found a new form in trying to impose centralized order on decentralized specialists in a chaotic process: economic micromanagement via computer modeling! It will probably work about as well as computer modeling predicting man's impact on global warming.




October 2, 2008
In response to: Should we leave the economy to economists?
Ralph commented:

So socialism has found a new form in trying to impose centralized order on decentralized specialists in a chaotic process: economic micromanagement via computer modeling! It will probably work about as well as computer modeling predicting man's impact on global warming.




October 2, 2008
In response to: Should we leave the economy to economists?
Goshawk commented:

There are two alternatives. Don't bail out the poorly managed financial groups or take the bailout and give it as a stimulus to the over 18 voting (citizen) population. Recession or runaway inflaction versus more business as usual with the bailout?
I would be eager to hear any alternatives.




October 2, 2008
In response to: Should we leave the economy to economists?
Policebox commented:

Interestingly enough, this isn't the first time a physicist has shaken economic theory. Back in the mid 80's a physicist got noticed because he was proposing an economic model of a steady state economy. He pointed out that the models currently used were dependent on growth for sustainability. Consequently economists wanted growing populations and resource usage, but that was contrary to the reality of limited resources such as land, food, and energy. He pointed out that growth was not sustainable, so we have to devise an economic model that allows for ongoing investment without growth related returns. I wish I could remember his name.




October 2, 2008
In response to: Should we leave the economy to economists?
Goshawk commented:

I apologize for the spelling above.




October 2, 2008
In response to: Should we leave the economy to economists?
Goshawk commented:

Herman Daly if memory serves, Policebox.




October 3, 2008
In response to: Should we leave the economy to economists?
CATHERINE FRENCH commented:

Scientific fraud even for Global Warming scientists -- I have worked with a lot of scientists for quite some time, including GW scientists. So people think that all Scientists (global warming included) are pure, untainted, and never have any hidden problems, issues, or agendas?




October 3, 2008
In response to: Should we leave the economy to economists?
NoOracleHere commented:

This article reminds me of some work that W. Brian Arthur did around 1994-97 where he examined mechanisms of positive feedback at work in the economy. Positive feedback occurs when something feeds on itself. A common example of positive feedback is compounded interest. You earn interest on the interest, and the earnings feed on themselves. Another example is a bomb.

Whereas previous economists mostly studied negative feedback mechanisms that make the overall system stable and predictable




October 3, 2008
In response to: Should we leave the economy to economists?
NoOracleHere commented:

I’ll try again. This article reminds me of some work that W. Brian Arthur did around 1994-97 where he examined mechanisms of positive feedback at work in the economy. Positive feedback occurs when something feeds on itself. A common example of positive feedback is compounded interest. You earn interest on the interest, and the earnings feed on themselves. Another example is a bomb.

Whereas previous economists mostly studied negative feedback mechanisms that make the overall system stable and predictable; systems that tend toward equilibrium. Positive feedback mechanisms are those that make a system chaotic and unpredictable. I suppose economists may be forgiven if they assume that given a positive feedback and a negative feedback in the same economy, that they would/should somehow cancel. But the reality is that when you add a positive feedback to a negative feedback, you get a system that contains both a positive feedback and a negative feedback. This system might be called complex. Brian Arthur’s work was essentially a study of complexity at work in our economy.

I believe more economists today are ready to acknowledge the complex, even chaotic nature of the markets and even the economy as a whole. But I don’t think they know what to make of it. If you study a chaotic system you might just return to the starting point and say something like, “Yes, it’s chaotic, now we know why, and isn’t it a shame”. But the study of chaotic systems can also expose properties analogous to “temperature”, or the degree of chaos, and the things that affect the chaotic system.

I think economists need to study and to make policy makers aware that the policies we have adopted over the last 25 years have contributed to the degree to which positive feedback mechanisms have ruled the economy. These are policies that encourage speculation and leverage. Our policies have been opposite of anything that would cool a speculative economy – deficit spending, stimulus packages, bank deregulation, etc. We have passed tax cuts that reward speculation – cutting capital gains and dividends taxes. We are suffering a credit crisis right now that is a crisis of leverage (investing other people’s money). The bailout plan needs to be examined under the light of what it means to a chaotic economy that tends to feed on itself. It also needs to be examined against the backdrop of a rescue for the proprietors of leverage when the government itself is heavily leveraged in the government debt. If our addiction to foreign oil is frightening, our addiction to foreign debt is absolutely terrifying. This is also a system that has fed on itself, and we are now going to draw on that (gov’t debt) to finance the bailout. There’s a lot of stored energy there and I fear we are trading one Pandora’s box for another.

If this article is saying “Economists WAKE UP”, then I say amen.





December 21, 2008
In response to: Should we leave the economy to economists?
RogAlb commented:

Economists shouldn't be trusted with anything, but nor should anyone who proposes a rational solution to an irrational problem. Economists are bound by their rationalist, hedonistic calculating assumptions. Break out of that paradigm and things could get interesting. Thorstein Veblen (died 1929) pointed to some interesting alternatives in his books, particularly, The Place of Science in Modern Civilization or in his article critiquing Marginal Utility Theory. There's lots of interesting theory out there, but what matters is politics. Power. Not economic theory.





POST A COMMENT
Display Name or Registered Users Login Here.
Please restrict submissions to less than 7,000 characters (including any HTML formatting).

Change Image
Before submitting this form, please type the characters displayed above.
Note the letters are NOT case sensitive.

Advertisement



Advertisements






©2009 Reed Business Information, a division of Reed Elsevier Inc. All rights reserved.
Use of this Web site is subject to its Terms of Use | Privacy Policy
Please visit these other Reed Business sites