Greg Mankiw: Why Aspiring Economists Need Math - 經濟

為什麼我們要學數學? Greg Mankiw 這篇文章值得一讀再讀.

http://gregmankiw.blogspot.com/2006/09/why-aspiring-economists-need-math.html

FRIDAY, SEPTEMBER 15, 2006
Why Aspiring Economists Need Math
A student emails me a question about the use of math in economics:

Dear Dr. Mankiw,

Hi, I am an undergraduate student studying economics in Michigan.
I have recently become a big fan of your blog. I found your
"Advice for Students" very helpful to professional economist
-wannabes like me, and especially, those considering graduate
study in economics. Your suggestion on math preparation for
undergrads landed me on one simple question: "Do economists
really use all that math?"

I was wondering if you could tell me how closely math and the
works of professional economists at international organizations,
such as World Bank and IMF, are related?

I look forward to your answer. Thank you in advance!

Best Regards,
[name withheld]

A student who wants to pursue a career in policy-related
economics is advised to go to the best graduate school he or she
can get into. The best graduate schools will expect to see a lot
of math on your undergraduate transcript, so you need to take it.
But will you use a lot of differential equations and real
analysis once you land that dream job in a policy organization?
No, you won't.

That raises the question: Why do we academics want students that
have taken a lot of math? There are several reasons:

1. Every economist needs to have a solid foundation in the basics
of economic theory and econometrics, even if you are not going to
be either a theorist or an econometrician. You cannot get this
solid foundation without understanding the language of mathematics
that these fields use.

2. Occasionally, you will need math in your job. In particular,
even as a policy economist, you need to be able to read the
academic literature to figure out what research ideas have policy
relevance. That literature uses a lot of math, so you will need to
be equipped with mathematical tools to read it intelligently.

3. Math is good training for the mind. It makes you a more
rigorous thinker.

4. Your math courses are one long IQ test. We use math courses
to figure out who is really smart.

5. Economics graduate programs are more oriented to training
students for academic research than for policy jobs. Although
many econ PhDs go on to policy work, all of us teaching in
graduate programs are, by definition, academics. Some academics
take a few years off to experience the policy world, as I did
not long ago, but many academics have no idea what that world
is like. When we enter the classroom, we teach what we know.
(I am not claiming this is optimal, just reality.) So math
plays a larger role in graduate classes than it does in many
jobs that PhD economists hold.

Is it possible that admissions committees for econ PhD programs
are excessively fond of mathematics on student transcripts?
Perhaps. That is something I might argue with my colleagues
about if I were ever put on the admissions committee. But a
student cannot change that. The fact is, if you are thinking
about a PhD program in economics, you are advised to take math
courses until it hurts.

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