Come Tuesday evening, millions of Americans will be glued to their TV screens or refreshing their browser windows to see the latest election results, all awaiting a final race call. (Although we may not know the next president until days later.)

Counting ballots can take a while, but news organizations don’t necessarily have to wait until every ballot cast is counted before announcing a winner. They are often able to declare who won without the full returns, thanks to the work of teams colloquially known as “decision desks” – groups of political scientists, statisticians, pollsters and reporters who compile mountains of data, statistical models, etc. -on-the-ground reporting to understand which candidate is where, and how likely a candidate is to win a particular district, province or state.

Given the doubt that former President Donald Trump has sown over the past eight years, both about the electoral process and about the media, it is worth understanding in detail how the processes of projecting and declaring election results work, and why news consumers rely on have to trust those results. .

“Remember, we’re not electing anyone,” Anthony Salvanto, who oversees the network’s decision desk as CBS News’ executive director of elections and polls, told Vox. “That’s what the voters do. Election officials report on the vote, and what you get from us and the networks is our analysis of what they reported, as well as our firsthand reports from conversations with voters.

How exactly do news organizations find out who wins?

To figure out who won an election, news organizations like Fox News, CNN, Associated Press (AP), and others use a combination of data from election officials, statistical models, and polls and voter surveys.

The raw vote counts come in at the precinct, county, and state levels, and these auxiliary decision offices both ensure that the vote is in line with their expectations and make decisions in close contests. Those expectations are shaped by statistical models based on history and other voter information, such as geographic location, gender, age and more.

This year there are two major systems that the news media will rely on for their projections.

The AP and Fox News use a system called AP VoteCast, which debuted in 2018 and has been used in every national election since. Unlike past practice, VoteCast does not rely on exit polls, but instead uses large-scale online surveys of registered voters chosen at random from a probability-based sample, in an effort to obtain the most accurate information of the most representative sample.

Another method is used by the National Election Pool (NEP), which provides data to ABC News, CBS News, CNN and NBC News. The NEP relies on Edison Research to conduct three types of surveys: Election Day exit polls, in-person early voting exit polls, and likely voter polls to collect data on those likely to vote by mail, Rob Farbman, executive vice president at Edison Research, told Vox. (AP and Fox News used to be part of this group, but left after the 2016 election.)

(Decision Desk HQ, a private company that contracts with news organizations like The Economist and The Hill — and Vox.com in 2020 — does not use voter surveys, relying instead on a proprietary statistical methodology to project winners.)

Each outlet and agency creates its own criteria for interpreting these results.

Sometimes that can lead to one decision office getting ahead of the other, as in 2020 when Fox News’ decision office head Arnon Mishkin called Arizona for President Joe Biden much earlier than any other news source, including the AP, or when the headquarters from the Decision Desk called the race well ahead of other experts.

But when it comes time to make a call, our decision team will examine all the models we use, consult with the networks’ decision teams, and consider any data issues to ensure that the possibility of our call being incorrect is sufficiently remote ,” said Farbman. “In general, we will not call until we have 99.5 percent confidence in the call.”

Similarly, the AP won’t call an election until “we are confident that there is no chance the trailing candidate can catch up,” said David Scott, the AP’s vice president and chief of news strategy and operations.

The combination of inputs allows the services to accurately understand who won each of the approximately 5,000 elections taking place this year, from the presidential race to local elections and ballot measures. And they can do it quickly, without having to wait for election officials to count every vote. That’s true even in the event of a tight race (as expected in the presidential race), although it’s a little more complicated to pinpoint it.

“When you get a really close race, you look at where the outstanding votes are, the votes that haven’t been reported yet, and you look at the kinds of places where the excellent votes are coming from,” Salvanto says. , from CBS News, said. “You look at whether it’s a mail-in ballot or an Election Day ballot, whether there are any differences in the patterns you’ve seen by voting type.”

Along the way, news organizations keep viewers informed as polls close and votes come in, showing the public that the data used to make calls is accurate.

“We’ll tell you if our models show it’s a toss-up or if it leads one way or another,” Salvanto said. “We will show you in real time where the counted votes are coming in – from which counties, which parts of the state, and where it is still outstanding, where we know there are registered voters, and we know there are still reports to come, so that the viewer can see the whole picture, as we see it.”

Of course, these methods are not perfect. Very occasionally, news organizations call a race incorrectly. The most dramatic example was in 2000, when news networks initially called Florida for Al Gore. Mistakes can happen – decision agencies are human beings, after all – but when they do, organizations try to correct them as quickly as possible. Still, mistakes are incredibly rare, so on Election Day (and the days after) you can trust that you’re seeing the real results.