The AP has called winners in elections for more than 170 years. Here’s how it’s done

By ROBERT YOON

WASHINGTON (AP) — One question will be asked over and over on election night: Who won?

The Associated Press will answer that question for nearly 5,000 contested races across the United States and up and down the ballot, from president and state ballot measures to a variety of local offices.

The AP has compiled vote results and declared winners in elections for more than 170 years, filling what could otherwise be a critical information void of up to a month between...