Wednesday, January 2, 2013
Only fools claim to know the future – by John Kay
At this season it is customary to look back on the achievements of the year that is past and to consider what may unfold in the year to come. Nate Silver, the young statistician who became an unexpected hero of 2012, is relevant to both exercises.
Many experts thought the American election too close to call but Mr Silver, though reviled by the Republicans, insisted that Barack Obama was likely to be comfortably re-elected. His prediction received attention because his forecasts of results four years earlier had proved very accurate. When Mr Silver was again proved right, his publisher cashed in and his book on prediction,
The Signal and the Noise
, became a bestseller.
There is no crystal ball behind Mr Silver’s success: just diligent work, obtaining disaggregated polling data, and assembling them with a sceptical mind that is well-informed about qualitative as well as quantitative factors relevant to the results. However, Mr Silver’s care, and his reliability, put popular pundits to shame. He exemplifies – and in his book reiterates – the distinction between hedgehog and fox made by the political scientist Philip Tetlock (following Isaiah Berlin, following Tolstoy, following Erasmus, following Archilochus). The hedgehog knows one big thing, the fox many little things. The hedgehog attracts public attention, but the fox is better at forecasting.