Friday, May 30, 2014

Tim Harford: An astonishing record – of complete failure

Link to article: An astonishing record – of complete failure 
‘In 2008, the consensus from forecasters was that not a single economy would fall into recession in 2009’

In the 2001 issue of the International Journal of Forecasting, an economist from the International Monetary Fund, Prakash Loungani, published a survey of the accuracy of economic forecasts throughout the 1990s. He reached two conclusions. The first was that forecasts are all much the same. There was little to choose between those produced by the IMF and the World Bank, and those from private sector forecasters. The second conclusion was that the predictive record of economists was terrible. Loungani wrote: “The record of failure to predict recessions is virtually unblemished.”

Now Loungani, with a colleague, Hites Ahir, has returned to the topic in the wake of the economic crisis. The record of failure remains impressive. There were 77 countries under consideration, and 49 of them were in recession in 2009. Economists – as reflected in the averages published in a report called Consensus Forecasts – had not called a single one of these recessions by April 2008.

This is extraordinary. Bear in mind that this is not the famous complaint from the Queen that nobody saw the financial crisis coming. The crisis was firmly established when these forecasts were made. The Financial Times had been writing exhaustively about the “credit crunch” since the previous summer. Northern Rock had been nationalised in the UK and Bear Stearns had collapsed in the US. It did not take a genius to see that trouble was on the way for the wider economy.

More astonishing still, when Loungani extends the deadline for forecasting a recession to September 2008, the consensus remained that not a single economy would fall into recession in 2009. Making up for lost time and satisfying the premise of an old joke, by September of 2009, the year in which the recessions actually occurred, the consensus predicted 54 out of 49 of them – that is, five more than there were.
The obvious conclusion is that forecasts should not be taken seriously. There is not a lot of point asking an economist to tell you what will happen to the economy next year – nobody knows. It is still a source of constant wonder to me that the demand for forecasts – in economics and elsewhere – remains undiminished.

John Maynard Keynes famously looked forward to a day when “economists could manage to get themselves thought of as humble, competent people, on a level with dentists”.

It’s a nice piece of self-deprecation, but it’s also an analogy worth exploring. We don’t expect a dentist to be able to forecast the pattern of tooth decay. We expect that she will offer good practical advice on dental health and intervene to fix problems when they occur. We should demand much the same from economists: proven advice about how to keep the economy working well and solutions when the economy malfunctions. And economists should bear in mind that no self-respecting dentist would be caught dead forecasting when your teeth will fall out.