How does the Associated Press call an election?

Many of you probably remember being parked in front of your TV as the votes rolled in on Nov. 7, 2000. It was election night. George W. Bush vs. Al Gore.

Despite losing the popular vote by over half a million votes, Bush narrowly edged out Gore by a mere 5 electoral votes in a presidential race that remains the closest electoral college margin of victory in the 21st century. The Supreme Court ultimately decided the winner in that race after legal challenges.

How do some media organizations call an election before it’s officially decided? Some have their own election analysts. Others, including NPR, rely on reporting from the Associated Press for breaking news from all around the country. Especially on election night. 

As the votes roll in, the AP is regarded as the definitive source for when a state gets called in favor of one candidate or the other. It’s how we find out who our next president is going to be. 

How exactly does the process work?