Nate Silver fared terribly in Thursday’s UK election: In his pre-election forecast, he gave 278 seats to Conservatives and 267 to Labour. Shortly after midnight, he was forecasting 272 seats for Conservatives and 271 for Labour. But when the sun rose in London on Friday, Conservatives had an expected 329 seats, against Labour’s 233.
The fault, Silver claimed, was with the polling: “It’s becoming increasingly clear that pre-election polls underestimated how well Conservatives would do and overestimated Labour’s result,” the statistician guru wrote in the wee hours of the morning. (He also overestimated the Liberal Democrats’ result by roughly 20 seats).
But the problem went beyond the UK. “The World May Have A Polling Problem,” Silver asserted. “In fact, it’s become harder to find an election in which the polls did all that well.” Silver went on to cite four examples where the polls had failed to provide an accurate forecast of the election outcome: the Scottish independence referendum, the 2014 U.S. midterms, the Israeli legislative elections, and even the 2012 U.S. presidential election, where “Obama beat the final polling averages by about 3 points nationwide.”