College football's post-Week 13 SP+ rankings

We're almost to the finish line. The table is set for next week's conference championship games, from Georgia-Alabama to Liberty-NMSU, and from the standpoint of predictive ratings, things look a lot like they did a week ago. The top four remain the same in this week's SP+ ratings, though Ohio State's rating slipped a bit following Saturday's loss to Michigan. The Buckeyes are now in a dead heat with Oregon and Penn State for the No. 3 spot, and the top two have distanced themselves a bit. And from a predictive standpoint, Washington appears to be leaking some oil as it approaches the Pac-12 championship.

Below are this week's SP+ rankings. 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.

SP+ is indeed 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.

Here are the full rankings: