ROBERT J. SHILLER Published: November 1, 2008

ALAN GREENSPAN, the former Federal Reserve chairman, acknowledged in a Congressional hearing last month that he had made an “error” in assuming that the markets would properly regulate themselves, and added that he had no idea a financial disaster was in the making. What’s more, he said the Fed’s own computer models and economic experts simply “did not forecast” the current financial crisis.

Mr. Greenspan’s comments may have left the impression that no one in the world could have predicted the crisis. Yet it is clear that well before home prices started falling in 2006, lots of people were worried about the housing boom and its...  full article