Forecasting for a Swing
By Arnold Kling
Joe Keohane writes about Nouriel Roubini,
For a prophet, he’s wrong an awful lot of the time. In October 2008, he predicted that hundreds of hedge funds were on the verge of failure and that the government would have to close the markets for a week or two in the coming days to cope with the shock. That didn’t happen. In January 2009, he predicted that oil prices would stay below $40 for all of 2009, arguing that car companies should rev up production of gas-guzzling SUVs. By the end of the year, oil was a hair under $80, Hummer was on its way out, and automakers were tripping over themselves to develop electric cars. In March 2009, he predicted the S&P 500 would fall below 600 that year. It closed at over 1,115, up 23.5 percent year over year, the biggest single year gain since 2003.
It would appear that Roubini’s strategy is to make forecasts that differentiate himself from the consensus forecast. This allows him to be spectacularly right sometimes and spectacularly wrong sometimes. As long as he succeeds in getting everyone to remember the right forecasts more clearly than the wrong ones, he becomes a prophet.
In tournament bridge, this strategy is known as “playing for a swing.” You deliberately try to make a bid that you think others holding your cards would not make, in order to create a different result. As you might expect, this strategy loses on average, but when it works you get a really good score. But you should not judge a bridge player who plays for swings just by the times that it works.