Polling and Prediction in the 2016 Presidential Election

Donald Trump was elected president of the United States on 8 November 2016. Within hours, TV pundits were declaring, “Data is dead.” Is this a case of water everywhere but not a drop to drink? It appears so on the surface. More than 250 nationally representative voter-preference surveys were done after the Republicans selected Trump for president and Mike Pence for vice president and the Democrats selected Hillary Clinton for president and Tim Kaine for vice president. The primaries saw even more highquality random digitaldial and online surveys. Perhaps more than 800,000 citizens were interviewed nationally, with tens of thousands more in key battleground state polls over the year leading up to the election. Trump was widely predicted to lose both the popular and Electoral College vote. Reputable experts gave Trump no greater than a 40 percent chance of victory,1 and some gave Clinton an 85 percent chance.2 Anonymous reports say even Trump campaign leaders thought their candidate would lose. Yet, the morning after the election, Trump had won the Electoral College by a comfortable, if still historically Polling and Prediction in the 2016 Presidential Election