Oliver Blanchard in the WSJ blog:
#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.