Supposedly incorrect polling has shaped politics in the U.K. and the U.S. in recent years. The improbable became the real following Donald Trump's election to U.S. President, the U.K.'s vote to leave the European Union last June and the Conservative party's victory in the 2015 General Election.
Pollsters have had to rethink their strategies. In March 2016, an independent review by the British Polling Council with regards to the last General Election revealed that pollsters had made two key errors: they had not contacted a sufficient number of traditional Conservative voters, nor had they appropriately accounted for the fact that younger demographics, though more likely to vote left, were less reliable at turning up on polling day.
Anthony Wells, director of political and social research at polling company YouGov, told CNBC via e-mail that the company had "invested in focusing (its) recruitment of those groups that were underrepresented in 2015: people less interested in politics, with lower levels of education or (who) did not vote in the last election." The accuracy of traditional telephone polling was also questioned. But Andrew Hawkins, chairman of pollster ComRes, argued that the method "will not become obsolete," offering that it was one of the few ways of guaranteeing a "truly random sample."
The Brexit referendum complicated matters. Hawkins said that Brexit was difficult to predict because it "motivated people to be politically active who wouldn't have been so otherwise." He argued that there was little evidence this sentiment would carry through to June's snap election, due, for example, to the U.K.'s first past the post voting system and the election being focused on more than one single issue.