Here's How Networks Call The Presidential Race

There are four things to remember this election night while waiting for results.

First, expect big swings in states where there are close races. That’s because historically, and based on polling this year, Democrats are expected to have an advantage in early and mail-in voting.

In a state like Ohio, where those votes are counted first on Election Day, Joe Biden will appear to be ahead of Donald Trump, said Lauren Copeland of Baldwin Wallace University’s polling institute.

“And then Ohio is going to start counting the in-person vote on Election Day and the results are going to start to swing back toward Trump,” Copeland said.

From there, the race in Ohio could come down to ballots mailed by Election Day, received up to ten days after polls close. And those votes are likely to swing the race back toward Biden.

“It could be a long few weeks in Ohio. They don’t certify the vote until three weeks after the election,” Copeland said.

Second, n etworks are going to be careful about making calls in close states.

Typically, about 40 percent of votes are cast early, 60 percent on Election Day. But because of the unique nature of this year’s elections, those numbers are expected to be flipped.

No one knows how long processing and counting the flood of mail in ballots will take, said Phillip Stark, a statistician and elections expert at University of California, Berkeley.

“My hope would be that there’s a very clear majority for one candidate or another as of Election Day and that that majority is kept as the vote-by-mail ballots get tabulated,” Stark said.

His concerns come from President Trump’s unfounded doubts about the security of mail-in ballots and what could happen if the apparent winner of a state on Election Night actually loses that state days or weeks later when results are made official.

A network making a call too early would add to the doubts about those results.

Also, official results are never certified on Election Night.

It’s not some kind of 2020 anomaly. Every state has its own canvassing period – the time allowed by law to count all the votes. In Ohio it’s normally 21 days, but this year counties have 15 days to report results to Ohio’s secretary of state for certification.

Just about every election is called by networks and news outlets the night of the election, though.

This year may be different.

“For one thing the data already shows there is going to be very, very extensive turnout, turnout that exceeds what we’ve seen in the past,” said Larry Rosin, president of Edison Research, a New Jersey-based company that compiles precinct-level results, county results and exit polling on Election Day.

Rosin’s company is part of the National Election Pool and collects the data for ABC, CBS, NBC and CNN, which all make their own calls on Election Night, or after.

This year, like every year, some states will be called by networks as soon as polls close, once the first vote counts come in.

“If we're leaning toward a call off the exit poll, that often will push us over the threshold that we need to determine a state because that sample of precincts will show us the accuracy or lack of accuracy of the exit poll,” Rosin said.

He added that they don’t have models for this year’s record numbers of mail-in votes. So they may have to wait for more of those returns than normal. And there’s litigation already underway that could slice into the number of ballots counted.

Finally, different news outlets use different methods for calling a race.

NPR uses the Associated Press’s race calls; the AP has been calling elections since before the Civil War. Fox News left the National Election Pool after 2016.

Those outlets avoid exit polls altogether, using more than 140,000 survey responses and reported results on Election Night instead. That will likely make their calls a little slower and a little more definitive.