John Cassidy Interviews Richard Thaler
Introduction (Via The New Yorker)
Thaler, one of the founders of behavioral economics, was out of town when I visited Chicago. I subsequently caught up with him on the phone, and I began by asking him what remained of the efficient-markets hypothesis, which he has long questioned.
Thaler: Well, I always stress that there are two components to the theory. One, the market price is always right. Two, there is no free lunch: you can’t beat the market without taking on more risk. The no-free-lunch component is still sturdy, and it was in no way shaken by recent events: in fact, it may have been strengthened. Some people thought that they could make a lot of money without taking more risk, and actually they couldn’t. So either you can’t beat the market, or beating the market is very difficult—everybody agrees with that. My own view is that you can [beat the market] but it is difficult.
The question of whether asset prices get things right is where there is a lot of dispute. Gene [Fama] doesn’t like to talk about that much, but it’s crucial from a policy point of view. We had two enormous bubbles in the last decade, with massive consequences for the allocation of resources.
When I spoke to Fama, he said he didn’t know what a bubble is—he doesn’t even like the term.
I think we know what a bubble is. It’s not that we can predict bubbles—if we could we would be rich. But we can certainly have a bubble warning system. You can look at things like price-to-earnings ratios, and price-to-rent ratios. These were telling stories, and the story they seemed to be telling was true.