College football post-bowl SP+ rankings

Caesars by William Hill lists Alabama as an eight-point favorite over Ohio State in January 11's national title game. SP+, however, sees something a little closer. With bowl season in the books, it gives Nick Saban's Crimson Tide a 4.3-point advantage over Ryan Day's Buckeyes.

This is a tricky game to evaluate. On one hand, Alabama was one of the biggest overachievers of the season in terms of SP+ projections. Even though they rank a clear first overall, the Tide have still overachieved projections by an average of 9.7 points per game. That the line gives them more of a cushion, then, makes sense.

On the other hand, SP+ liked Ohio State far more than the market did before the Buckeyes' dominant performance against Clemson. That it likes them more than the market makes sense, too.

We've got eight more days until we find out which impression is correct.

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.

More than ever, it's 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.