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 econom
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. And, as an encore, there were 15 recessions in 2012. None were foreseen in the spring of 2011 and only two were predicted by September 2011.
Predictions from multinational organisations such as the IMF and the Organisation for Economic Co-operation and Development have remained very similar to the private sector consensus – similarly bad, that is.
We should not blame economics alone for our inability to peer into the future of a complex world. In 2005, Philip Tetlock, a psychologist, published a landmark work with the title Expert Political Judgement. Tetlock found that throughout the 1980s and 1990s, political and geopolitical forecasts had been scarcely better than guesswork. It made little difference whether the forecaster was an academic, journalist or diplomat, a historian or a political scientist. Forecasting is difficult, it turns out. (Supply your own punchline.) As for Tetlock, he is currently conducting a follow-up study to see whether forecasting practices can be saved.
Why are forecasts so poor? The chief explanation is that the economy is complicated and we don’t understand it well enough to make forecasts. We don’t even fully understand recent economic history.
Ben Chu, economics editor of The Independent, recently took a look at the UK recession of the 1990s in the light of two decades of data revisions. From the vantage point of 1995, the economy in late 1992 was slightly smaller than the economy in early 1988. But today’s best guess is that the economy of late 1992 was almost 6 per cent larger than in early 1988. The Office for National Statistics has substantially revised its view.
Not only is it difficult to forecast the future, then – forecasting the past isn’t straightforward either. What chance does any prognosticator have?
A second explanation for forecasting’s fallibility is that there is little incentive to do better. The kind of institutional chief economist whose pronouncement makes it into Consensus Forecasts will stick to the middle of the road. Most countries, most of the time, are not in recession, so a safe strategy is never to forecast one. Of course there are the mavericks who receive media attention for making provocative predictions and are lionised when they are right. Their incentives are different but it is unclear that their overall track record is any better.
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.
Twitter: @TimHarford; Tim Harford’s latest book is ‘The Undercover Economist Strikes Back’
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