Better poll sampling would have cast more doubt on the potential for Hillary Clinton to win the 2016 election

Donald Trump's 2016 election victory took many by surprise - most of the polling had suggested a victory for Hillary Clinton. But were the polls wrong? In new research Manfred te Grotenhuis, Subu Subramanian, Rense Nieuwenhuis, Ben Pelzer and Rob Eisinga examine the election polls' accuracy by randomly sampling from each state's observed voters for Clinton or Trump. They find that a relatively small polling bias which saw Republicans underrepresented in a number of key states tipped the polling – and therefore the predicted probability that she would win – in favor of Hillary Clinton.