The Return of History
By DAVID BROOKS
Published: March 26, 2010
After the crash, economics will have to acknowledge its methodological failures and come to resemble an art rather than a science.
How Did Economists Get It So Wrong?
By PAUL KRUGMAN
Published: September 6, 2009
The Great Recession was the result not only of lax regulation in Washington and reckless risk-taking on Wall Street but also of faulty theorizing in academia.
How did Paul Krugman get it so Wrong?
John H. Cochrane
This article is a response to Paul Krugman’s New York Times Magazine article, ‘How Did Economists Get It So Wrong?’ Krugman’s attack on modern economics – and many adhominem attacks on modern economists – display a deep and highly politicised ignorance of what economics and ﬁnance is really all about, and a striking emptiness of useful ideas.
The future of economics.
How should economics change? Krugman argues for three incompatible changes.
First, he argues for a future of economics that “recognizes flaws and frictions,” and incorporates alternative assumptions about behavior, especially towards risk-taking. To which I say, “Hello, Paul, where have you been for the last 30 years?” Macroeconomists have not spent 30 years admiring the eternal verities of Kydland and Prescott’s 1982 paper. Pretty much all we have been doing for 30 years is introducing flaws, frictions and new behaviors, especially new models of attitudes to risk, and comparing the resulting models, quantitatively, to data. The long literature on financial crises and banking which Krugman does not mention has also been doing exactly the same.
Second, Krugman argues that “a more or less Keynesian view is the only plausible game in town,” and “Keynesian economics remains the best framework we have for making sense of recessions and depressions.” One thing is pretty clear by now, that when economics incorporates flaws and frictions, the result will not be to rehabilitate an 80-year-old book. As Paul bemoans, the “new Keynesians” who did just what he asks, putting Keynes inspired price-stickiness into logically coherent models, ended up with something that looked a lot more like monetarism. (Actually, though this is the consensus, my own work finds that new-Keynesian economics ended up with something much different and more radical than monetarism.) A science that moves forward almost never ends up back where it started. Einstein revises Newton, but does not send you back to Aristotle. At best you can play the fun game of hunting for inspirational quotes, but that doesn’t mean that you could have known the same thing by just reading Keynes once more.
Third, and most surprising, is Krugman’s Luddite attack on mathematics; “economists as a group, mistook beauty, clad in impressive-looking mathematics, for truth.” Models are “gussied up with fancy equations.” I’m old enough to remember when Krugman was young, working out the interactions of game theory and increasing returns in international trade for which he won the Nobel Prize, and the old guard tut-tutted “nice recreational mathematics, but not real-world at all.” He once wrote eloquently about how only math keeps your ideas straight in economics. How quickly time passes.
Again, what is the alternative? Does Krugman really think we can make progress on his – and my – agenda for economic and financial research — understanding frictions, imperfect markets, complex human behavior, institutional rigidities – by reverting to a literary style of exposition, and abandoning the attempt to compare theories quantitatively against data? Against the worldwide tide of quantification in all fields of human endeavor (read “Moneyball”) is there any real hope that this will work in economics?
No, the problem is that we don’t have enough math. Math in economics serves to keep the logic straight, to make sure that the “then” really does follow the “if,” which it so frequently does not if you just write prose. The challenge is how hard it is to write down explicit artificial economies with these ingredients, actually solve them, in order to see what makes them tick. Frictions are just bloody hard with the mathematical tools we have now.