Come Tuesday night, millions of Americans will be glued to their TV screens or refreshing their browser windows to see the latest election results, all in anticipation of one last call. (Although we may not know the next president until days later.)

Counting ballots can take some time, but news organizations don’t necessarily have to wait for every vote to be counted before announcing a winner. They are often able to tell who won without the full returns, thanks to the work of teams known colloquially as “decision bureaus”—groups of political scientists, statisticians, investigators, and reporters who use mountains of data, statistical models, and more. -field reporting to understand which candidate is where and how likely a candidate is to win a particular constituency, county or state.

Given the doubt that former President Donald Trump has sown over the past eight years, both in terms of the electoral process and the media, it is worthwhile to understand in detail how the processes of designing and calling election results work. and why news consumers should trust these results. .

“Remember we don’t choose anyone” Anthony Salvantowho as executive director of elections and polling at CBS News oversees the network’s decision office, told Vox. “Voters do that. Election officials are reporting the vote, and what you’re getting from us and the networks is our analysis of what they’ve reported, as well as our first-hand reports from talking to voters.”

How exactly do news organizations figure out who wins?

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

Raw vote counts occur at the precinct, county, and state levels, and these help desks ensure that the vote is in line with their expectations and to make decisions in close contests. These 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 main systems that the news media will rely on for their projections.

The AP and Fox News use a system called AP VoteCastwhich debuted in 2018 and has been used in all national elections since then. In a change from previous practice, VoteCast does not rely on exit polls, but instead uses large-scale online surveys of registered voters who are randomly selected from a probability samplein an attempt to obtain the most accurate information from the most representative sample.

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

(Headquarters of the decision office, a private company that contracts with news organizations including the Economist and The Hill — and Vox.com in 2020 — doesn’t use voter polls and instead relies on a proprietary statistical methodology to project winners.)

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

Sometimes this can lead to one decision office preempting the others, as in 2020 when Fox News chief of staff Arnon Mishkin called Arizona for President Joe Biden far earlier than any other news source, including the AP, or when the Decision Desk called the race well ahead of other pundits.

Generally, though, when it comes time to make a call, “Our decision team will review all the models we run, consult with the networks’ decision teams, and consider any potential data issues to make ensure that the possibility of our call being incorrect. it’s small enough,” Farbman said. “Generally, we will not make a call unless we are 99.5% confident in the call.”

Similarly, the PA does not call elections until “we’re confident there’s no chance the trailing candidate will catch up,” according to David Scott, AP vice president and head of news strategy and operations.

The combination of entries allows the services to understand exactly who won each of the about 5,000 elections taking place this yearfrom the presidential race to local contests and ballot measures. And they can do it quickly, without having to wait for election officials to count each vote. This is true even in a close race (as the presidential race is expected to be), although calling them is a bit trickier.

“If you get a very close race, then you look at where the outstanding vote is, the vote that hasn’t been reported yet, and you look at the kind of places where the outstanding vote is coming from,” CBS News’ Salvanto said. “You look at whether it’s a mail-in vote or an Election Day vote, whether there are differences in the patterns that you’ve seen based on the type of vote.”

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

“We’ll tell you if our models show it’s a toss up or it’s leading one way or the other,” Salvanto said. “We’re going to show you, in real time, where the counted vote is coming in – from which counties, which areas of the state, and where it’s still open, where we know there are registered voters and we know there are still reports to come in, so the viewer can see the whole image as we see it.”

Of course, these methods are not perfect. Very occasionally, news organizations call a race wrong. The most dramatic example was in 2000, when news networks originally named Florida for Al Gore. Mistakes happen—after all, decision-making offices are made up of human beings—but when they do, organizations work to correct them as quickly as possible. Still, mistakes are incredibly rare, so on election day (and the days after) you can be sure to see the real results.