What did the worst financial crisis in 75 years teach academic economists
and policymakers?
#1: Humility is in
order.
The Great
Moderation [the economically tranquil period from 1987 to 2007] convinced too
many of us that the large-economy crisis - a financial crisis, a banking
crisis - was a thing of the past. It wasn’t going to happen again, except
maybe in emerging markets. History was marching on.
My generation,
which was born after World War II, lived with the notion that the world was
getting to be a better and better place. We knew how to do things better, not
only in economics but in other fields as well. What we have learned is that¹s
not true. History repeats itself. We should have known.
#2: The financial
system matters — a lot.
It’s not the first
time that we¹re confronted with [former U.S. Defense Secretary Donald] Rumsfeld
called “unknown unknowns,” things that happened that we hadn’t thought about.
There is another example in macro-economics:
The oil shocks of
the 1970s during which we were students and we hadn’t thought about it. It took
a few years, more than a few years, for economists to understand what was going
on. After a few years, we concluded that we could think of the oil shock as yet
another macroeconomic shock. We did not need to understand the plumbing. We
didn’t need to understand the details of the oil market. When there’s an
increase in the price of energy or materials, we can just integrate it into our
macro models - the implications of energy prices on inflation and so on.
This is different.
What we have learned about the financial system is that the problem is in the
plumbing and that we have to understand the plumbing. Before I came to the
Fund, I thought of the financial system as a set of arbitrage equations.
Basically the Federal Reserve would chose one interest rate, and then the
expectations hypothesis would give all the rates everywhere else with premia
which might vary, but not very much. It was really easy. I thought of people on
Wall Street as basically doing this for me so I didn¹t have to think about it.
What we have
learned is that that’s not the case. In the financial system, a myriad of
distortions or small shocks build on each other. When there are enough small
shocks, enough distortions, things can go very bad. This has fundamental
implications for macro-economics. We do macro on the assumption that we can
look at aggregates in some way and then just have them interact in simple
models. I still think that¹s the way to go, but this shows the limits of that
approach. When it comes to the financial system, it¹s very clear that the
details of the plumbing matter.
















