Week 11 of the college football season gave us a master class in randomness. The two biggest games of the week (LSU over Alabama and Minnesota over Penn State) were each decided, in part, by red zone turnovers -- Bama lost a completely unforced fumble inside the 10 and lost by five, and PSU threw three red zone interceptions and also lost by five. Were there other factors involved in these results? Of course. But reversing just a couple of particularly funky plays could have completely changed how we view four different national title contenders.
A good predictive system is designed to filter out as much noise as possible and avoid overreaction, and I like to think SP+ qualifies as a good predictive system (it is currently at 55% against the spread for the season, which is one good indicator). How did it react to these games?
LSU significantly closed the gap on Bama. Last week, the Crimson Tide were second in SP+ with a rating of 34.1 adjusted points per game, 4.5 ahead of the third-place Tigers. This week, their rankings haven't changed, but the gap has: LSU picked up 3.6 points and is only 0.9 points behind. What this means is, if the two teams were to play a rematch this coming week -- which I heartily encourage, by the way; that game in Tuscaloosa was so much fun to watch -- the Tide would be about a 3.5-point favorite in Tuscaloosa (I apply a 2.5-point home field advantage), and the Tigers would be about a 1.5-point favorite in Baton Rouge. Vegas might shade slightly more in LSU's direction, but based on what my eyeballs saw on Saturday, this seems about right to me.
The gap between PSU and Minnesota grew slightly. Last week, PSU's SP+ rating was 26.1 adjusted points per game, seventh in FBS, and Minnesota's was 21.5 (10th). PSU outgained the Gophers by 58 yards and created two more scoring opportunities (first downs inside the opponent's 40). That creates a win more often than not, but the randomness of turnovers made the difference. This week: PSU's rating is basically the same (26.0), while Minnesota's fell by a point (20.5). The Nittany Lions are still seventh, and the Gophers, packed into a crowded space in the ratings (No. 11 and 17 are separated by only 2.8 points), are 13th.
SP+ watched these two amazing games and changed one of four teams' rankings. Stats are nothing if not anti-social.
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.