Since the financial crisis started, economists have been lambasted for failing to predict it. But foretelling the future is always tricky, as any climate scientist will tell you. Foretelling the future of the economy is especially tricky because the very act of publishing forecasts will, if they are believed, affect the future path of the economy. At least the weather doesn’t respond to weather forecasts.

Suppose that in early 2007 economists had predicted that 2008 was going to be the year of financial collapse. Assuming that they were believed, people would have become a lot more cautious, and wary investors would have started to sell assets to ensure that they got out in time. In the blink of an eye, sellers would have been rushing into the market, asset prices would have plummeted and 2007 would have been the year of the financial collapse, not 2008. The economists would have