New FBI Letter to Congress: Decision Not to Prosecute Hillary Has 'Not Changed'

Emails: Clinton Asked Maid to Handle Classified Info

'His Biggest Fan': Grieving Parents Recall Donald Trump's Touching Letters

"When races get called, it's not just a matter of waiting for the numbers and reporting it to the world," Dana Perino said on I'll Tell You What.

"There is a lot of work that goes into figuring it all out," she said.

Chris Stirewalt gave a tour of the new Fox News Channel studio and "Nerd Tunnel" where all of the breaking election night calls will be made.

Stirewalt said Fox News vice president Bill Sammon will be making the final call, after consulting with the Decision Desk, on when to declare that a candidate has won a state.

The Decision Desk will be using, among other tools, exit polls:

"It's a poll that happens to be a particularly good poll...[partially due to] sample size," Stirewalt said, "A consortium of media outlets' [information] is pulled together to create this awesome sample of voters. The sample gets weighted...and matched up with the real vote."

"We hold that very closely. We have a special obligation [not to] affect the outcome of the election before the polls close."

He said that Fox News wants to "beat everybody all of the time" in making calls, "but it's never worth being wrong."

Bill Hemmer also took Perino and Stirewalt on a tour of the new and improved state-by-state 'BillBoard'.

Watch the full clip above and let us know what you think in the comments.

Pirro: Clinton's Guilt a 'Moot Point' -- 'She Cannot Take the Oval Office'

'You Can't Eat a Jay-Z': Trump Surrogate Says NY Mogul Best for Inner Cities

WATCH: A Look Back at Tucker Carlson's Time on the Curvy Couch