"predicting republiklan winners with only 9% of the votes in like a race 51 to 49%. And then show a dem winning 70 to 30% with almost 70% votes in and don't say anything."
I know you're exaggerating a little, but I get the gist. It's this though. They look at where the votes came from and what's left and the level of certainty they're feeling.
I remember Carville calling Pennsylvania for Biden when he was hundreds of thousands of votes down, just from knowing the outstanding vote was the Philly metro area, and knowing how many votes were still outstanding. It's inexact, more art than science really, but the people who do it for a living are pretty good at it. And Carville was right.
Score one for the Cajun.