Monday, June 13, 2011

The Sickness Beneath the Slump – By Robert Shiller





A half-century ago, there was a lively discussion among economists about the dynamics of price expectations. For example, Alain C. Enthoven, then of the Massachusetts Institute of Technology, and Kenneth J. Arrow of Stanford wrote in 1956 that expectations that extrapolate past price increases can produce economic instability. But that thinking was largely cast aside in the 1960s, when my profession embraced the theory that efficient markets formed by people holding rational expectations could explain virtually all economic activity.

As a result, economists in recent decades have not developed expectations theory much further. That needs to be corrected in coming years. In the meantime, this failing helps explain why the current crisis was generally unpredicted, and why its future course is so poorly understood.