Early voting in Detroit. Photo / Nick Hagen, The New York Times
Exit polls don’t have a very good track record, and they can contribute to misleading narratives on election night.
As you wait for votes to be counted and results to trickle in, you might be curious about whether the exit polls you sometimes see cited on TV or social media
can provide a preview of what’s to come.
Exit polls are surveys conducted as voters leave their polling places. The most widely cited are by Edison Research, for the National Election Pool, a coalition of broadcast news organisations. Unfortunately, exit polls don’t have a very good track record, and they can contribute to misleading narratives on election night.
As more polls close, more interviews are added to an exit poll’s sample, so the results evolve throughout the night. And while exit polls are eventually weighted to match the final vote outcome, that obviously can’t happen until after the election is over. So, on election night, the sample is weighted to reflect the known electorate, but that, too, changes as more votes are tallied. As a result, exit polls, especially early ones, sometimes seem to show trends that don’t turn out to be true after all the votes have been counted.
