The ignorance of macroeconomists

Brad DeLong and Paul Krugman offer some explanations for the fact that so many prominent macroeconomists are ignorant of macroeconomics. DeLong blames Milton Friedman for oversimplifying macroeconomics in an attempt to "hide how close to the Keynesians his own monetarist-libertarian model of the business cycle was." Krugman says Friedman isn't to blame: today's "freshwater" macroeconomists are "two intellectual generations of intellectual retrogression beyond that."

I think one problem is the economics profession's obsession with mathematics. It's not that math isn't useful, mind you. Mathematical model-building tightens an argument, ensures that it is internally consistent. I understand an economic argument much better after wading through the fifty equations an author uses to describe it than I do, say, reading the General Theory, which is almost entirely verbal. But a mathematical model is only worth plowing through if it has some relevance to real economic phenomena. Our graduate programs make little or no effort to ensure that the students they admit or the Ph.Ds they produce have any knowledge of the real world. Look at the advice American Economic Association gives to undergraduates aspiring to pursue a Ph.D in economics:

Students from a wide variety of backgrounds earn graduate degrees in economics. This includes economics and non-economics majors, those with and without prior graduate training, and those with and without prior economics employment experience... One criterion admissions committees use to gauge applicant qualifications is the GRE exam. Research by Stock, Finegan, and Siegfried... reveals that the average GRE quantitative score was 772 (out of a possible 800), and the average GRE verbal score was 562 (out of a possible 800) for the entering Ph.D. class of 2002. Among students in tier 1 schools*, the averages were 785 and 575; among students in tier 2 schools, the averages were 782 and 547; among students in tier 3 schools, the averages were 765 and 573, respectively.

785 math and 575 verbal! No wonder so many economics articles are unreadable!

The AEA suggests that students who want to get into a good graduate program had better take advanced calculus, advanced linear algebra, differential equations, stochastic processes, topology, real and complex analysis, and advanced probability theory. In other words, you're more likely to get into a graduate school as a math major than as an economics major! Again, I love math and the more math the better as far as I'm concerned. But it would be nice if graduate schools put some weight on knowledge of economics, history, political science, or some other aspect of the real world in addition to math. Is it not possible that someone who did not score 785 on his GRE (but has some facility with mathematics) yet has read Smith, Keynes, Marx, Hayek and Friedman, might be a better candidate for a Ph.D program than someone who has studied nothing but mathematics? Graduate schools have long since stopped requiring students to study the history of thought (or history or any other real-world discipline outside economics). If they also recruit solely on the basis of math preparation, why are we surprised when they turn out a generation of economists who know nothing of the economy?