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.
More on the CFP:
• Connelly's semifinal takeaways (E+)
• What's next for eliminated teams? (E+)
• First look at title game