Little gnomes somewhere are tabulating exit poll data and so will know the result of the presidential election before Americans finish voting. What are exit polls?
Exit polls are questionnaires that people are asked to fill out after they leave their polling place. These "ballots" are about 30 questions long and ask everything from age and sex to who people voted for and why. Voters fill out the questionnaires themselves and deposit them in boxes, so their answers, like their actual ballots, are secret. Exit polls are conducted across the country by Voter News Service, a consortium of the television networks ABC, CBS, CNN, Fox, and NBC, and the Associated Press. Today they will collect about 70,000 questionnaires from around the country. As the results are tabulated, VNS will be able to project winners of the presidential, congressional, and gubernatorial races. Since 1980, when they were first used to predict a presidential race, they have been overwhelmingly accurate.
In elections where the exit polls are widely in favor of one candidate, VNS is able to call the winner on the basis of that alone. In somewhat closer elections, exit poll data is combined with actual results from sample precincts to project a winner before all the votes are tallied. In races closer than that, VNS adds results from counties to say who won. And if it's really, really, really close, even VNS has to wait for almost all the votes to be counted. This doesn't mean that you will know when VNS knows. Since the 1980s politicians from Western states and others have denounced the practice of declaring winners before all the polls are closed nationally. So the networks promise every four years to keep their news to themselves (except for hints) until everyone finishes voting. During the presidential primaries, Slate published exit poll results before VNS members and subscribers released them but is not doing that today under threat of a lawsuit.
Exit polls were first conducted in 1964 as a minor part of a process that sampled key district voting results to project election outcomes. By the 1970s the surveys had become more extensive but were used by the networks to explain the election results, not to call them. In 1980 early exit poll data revealed a Reagan sweep that had not been reflected in the pre-election surveys. NBC used the information to project the winner at 5 p.m. EST. Jimmy Carter found the exit poll data so convincing that he conceded before the West Coast finished voting.
Explainer thanks Martin Plissner, former executive political director of CBS News and author of The Control Room: How Television Calls the Shots in Presidential Elections.