College football updated SP+ rankings after Week 13

As we head into college football's Championship Week, the sport's hierarchy, per SP+, couldn't be clearer. The No. 1 team is more than four points ahead of the No. 2 team, which is nearly three points ahead of No. 3, which is nearly two points ahead of No. 4, which is nearly two and a half points ahead of No. 5. The distance between No. 1 and No. 5 (11.4 points) is the same as the distance between No. 5 and No. 36!

Who's No. 1? You already know: Kirby Smart's Georgia Bulldogs. The Dawgs have been the class of college football in 2021. Whether we had a 12-team playoff or the old BCS, Georgia would be a significant favorite to win its first national title since 1980, but as things stand, they've got three games left to win the ring. And they'll be significant favorites in every game they play, even against Alabama in this week's SEC Championship.

What is SP+? In a single sentence, it's a tempo- and opponent-adjusted measure of college football efficiency. I created the system at Football Outsiders in 2008, and as my experience with both college football and its stats has grown, I have made quite a few tweaks to the system.

It is, as always, important to note that SP+ is intended to be predictive and forward-facing. It is not a résumé ranking that gives credit for big wins or particularly brave scheduling -- no good predictive system is. It is simply a measure of the most sustainable and predictable aspects of football. If you're lucky or unimpressive in a win, your rating will probably fall. If you're strong and unlucky in a loss, it will probably rise. It is a look at how teams should likely perform moving forward.