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 intended to be predictive and forward-facing. That is important to remember. 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.

The SP+ rankings generally perform well against the spread -- 52 to 54 percent success over a full season, which is excellent for a system projecting every game and not specifically adjusting for injury.

At this point in the year, the ratings are made up almost entirely of preseason projections, which you can find here. It's impossible to glean too much from just one week, but there were some standout performances, namely that of Wisconsin, which leaped from 14th to fifth by completely humiliating USF.