On election night, The Associated Press made the call that Democratic presidential candidate Joe Biden had won Virginia’s 13 electoral votes at 7:36 p.m. ET—a call other news outlets didn’t make until hours later. CNN, for example, called the state for Biden at 11:55 p.m. How did each station make such an important decision at drastically different times?

It comes down to strategy and technique, says Dan Kennedy, journalism professor at Northeastern.

“Each news organization came to its decision while trying to be as responsible as possible,” Kennedy says.

News outlets fill in their election maps by relying on election officials and volunteers to report the ballot count from each county in every state across the U.S., Kennedy says. They can also make educated predictions about which way certain states will go, based on exit polling and spot-checking certain counties where people reliably vote Republican or Democrat.

“What you’re looking for on election night are anomalies,” Kennedy says. “The question every outlet is asking is ‘Are the returns in line with what we expected, or is there some kind of anomaly that might indicate something new is going on?’”

This year’s election is also complex for news outlets because of a record number of early, mail-in, and absentee votes from people likely trying to avoid crowded polling stations during the COVID-19 pandemic.

In some states, including the crucial battleground states of Michigan, Wisconsin, and Pennsylvania, local rules prevented election officials from counting mail-in ballots until on or just before Election Day. This led to dramatic swings in results throughout the night as batches of votes were returned, and uncertainty Wednesday morning as those ballots were still being counted.

When the AP called Virginia, only about 10 percent of the votes had been returned, and it appeared that President Donald Trump, the Republican candidate, was solidly in the lead.

The Associated Press likely “spot checked” a representative sample of early returns, Kennedy says—and, with the knowledge that Democrats had won the state by considerable margins in the last three presidential elections, forecasted that the rest of the votes would play out similarly. They did.

On the other hand, journalists at CNN were diligent about not calling any state until the recorded vote total indicated it would tip one way or another, Kennedy says. CNN’s election map showed Virginia solidly for Trump even as the AP called it a Biden victory, because many of the early votes were for Trump. It wasn’t until more votes had been returned and the balance shifted toward Biden that CNN made its call.

In both cases, Kennedy says, journalists were making calculations about the surest way to ensure accuracy over the entire span of the night—something that was particularly important in this election, as Trump continued to make baseless claims of fraud.

“It’s a heavy weight of responsibility in terms of calling a race,” Kennedy says, “that’s not something any news organization wants to get wrong.”

For media inquiries, please contact Shannon Nargi at s.nargi@northeastern.edu or 617-373-5718.