Before the networks call the winners in a primary, they don't have much to talk about beside exit polls. (Neither, frankly, do we.) The exit polls are notoriously unreliable, especially because the networks update their numbers as new waves of data come in. (This helps them adapt their calculations as they learn more information about turnout, votes by region, etc.) But in a state like North Carolina, where nearly 500,000 people have already voted early, are exit polls faulty because they don't survey early voters?
No—not even a little bit. The name "exit poll" is misleading in states that have early voting because the pollsters don't just survey voters as they're exiting the polls. The same outfit conducts exit polls for all of the networks, and that outfit has already interviewed 400 people by telephone in North Carolina. Given past results and current projections, they're expecting early voters to make up 30 percent of all voters. So if turnout is around 1.33 million, which makes early voters 30 percent of the electorate, the exit polls will accurately incorporate early voters. If turnout tops 1.33 million, which some observers say it may, then they'll have to adjust their model.
Either way, the bases are covered. That's one reason fewer to distrust the exit polls. Many more to go.