Ohio State heads into the national title game as a projected 5.9-point favorite over Notre Dame, per the updated SP+ ratings. That's a pretty solid disagreement with the opening ESPN BET line of Ohio State -9.5, though it doesn't take into account Notre Dame's increasing injury issues. (SP+ isn't designed to react to injuries.)
The Fighting Irish have overcome injuries with relative ease all season, but the sportsbooks seem to be reacting to a pair of new offensive line injuries:
ESPN Bet projection: Ohio State 27.5, Notre Dame 18.0 (OSU -9.5, over/under 45.5)
SP+ projection: Ohio State 27.6, Notre Dame 21.7
One way or the other, however, the Buckeyes are the favorite. Following their 28-14 win over Texas in the Cotton Bowl semifinal, they rank first in defensive SP+ (2.8 points ahead of the No. 2) and third in offensive SP+ (up from ninth at the start of the College Football Playoff). Notre Dame has quite a bit to overcome to score its first national title in 36 years.
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.
Following its Mayo Bowl thumping of Virginia Tech, Minnesota moved up 1.1 points to a solid 26th overall, joining a large number of Big Ten teams in improving their ratings in bowl season. The conference went 10-6 in the postseason, 9-5 if you don't include Ohio State's win over Oregon in the Rose Bowl. The league's overall average is dragged down by quite a bit of dead weight, but that average still rose from 7.8 adjusted points per team before the postseason to 8.4 now.
That rise was countered by a corresponding drop in the ACC's average rating. The ACC began the postseason with an average rating of 6.8, 1.4 points ahead of the Big 12 and only 1.0 behind the Big Ten; after an abysmal 2-11 performance in bowls and the CFP, its average rating is 5.5, down 1.3 points and now slightly behind the Big 12's 5.6 in fourth place. Forty-something bowls can only have so much of an impact -- for comparison, there were 336 nonconference games before the bowls -- but the postseason dinged the ACC awfully hard, and justifiably so.