SP+ had a pretty good lay of the land in Week 5, going 56% against the spread and missing games by an average of only 12.1 points per game. Those are strong numbers, but we still saw plenty of unexpected results: Georgia struggled far more against Missouri than projected (same with Penn State vs. Northwestern), Oklahoma laid an egg against TCU, Minnesota fell to Purdue after posting four weeks of absolute dominance, and Utah destroyed Oregon State, among other games.
The result? No changes among the top four teams but plenty of surprises thereafter. We headed into this season not really knowing who the fourth-best team was after a strong top three, and while Michigan has given SP+ an answer in that regard, the No. 5 spot remains completely up for grabs.
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. 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.
This week's movers
We're going to try something a little bit different this week. Instead of noting the teams that moved up or down the most from a rankings standpoint -- congrats to JMU, Troy and Appalachian State for leading the way in that regard, and condolences to WKU, Air Force and SDSU for doing the opposite -- we're going to look at the teams whose ratings rose or fell the most.
Moving up
Here are the 10 teams whose ratings rose the most this week:
James Madison: up 9.1 adjusted points per game (which moved it from 68th to 34th in the rankings)
Georgia State: up 6.4 points (95th to 84th)
FIU: up 5.3 points (131st to 129th)
Troy: up 5.0 points (84th to 66th)
Appalachian State: up 4.8 points (53rd to 40th)
TCU: up 4.6 points (32nd to 21st)
Northwestern: up 3.9 points (99th to 88th)
Purdue: up 3.9 points (36th to 25th)
South Carolina: up 3.8 points (56th to 46th)
Arkansas State: up 3.8 points (104th to 94th)
There's a conference adjustment piece to the SP+ rankings that begins to kick in after about five games. Because the Sun Belt has overachieved projections by a good amount, this adjustment basically lifted all SBC teams a bit. Combine that with the fact that preseason projections get dropped by a solid amount after four games, and you see that James Madison, which just passed that four-game threshold, absolutely leaped up the table this week. The Dukes have been fantastic.
Moving down
WKU: down 5.0 points (49th to 75th in rankings)
Air Force: down 4.6 points (54th to 76th)
SDSU: down 4.1 points (88th to 103rd)
Fresno State: down 3.4 points (69th to 82nd)
MTSU: down 3.1 points (87th to 98th)
Army: down 3.0 points (77th to 86th)
Virginia Tech: down 2.6 points (79th to 87th)
UNLV: down 2.5 points (90th to 100th)
Central Michigan: down 2.5 points (89th to 99th)
Oklahoma: down 2.3 points (fifth to sixth)
Since college football is zero-sum, if something is rising, something else has to fall. The Mountain West has dramatically underachieved projections thus far, and the conference adjustment piece was therefore awfully unkind.
Really, I wanted to do this "ratings instead of rankings" thing to highlight Oklahoma. Following TCU's blowout of the Sooners in Fort Worth, the Horned Frogs' rating rose by 4.6 points, and OU's fell by 2.3, making it one of the most impactful games of the week in terms of overall change. But because the Sooners were pretty far ahead of the pack in fifth place heading into this week, that pretty steep drop only sent them from fifth to sixth.
OU has underachieved dramatically in the past two weeks, but the combination of preseason projections (which drop again by a good amount after six games) and strong performances over the first three weeks continue to prop the Sooners up a bit more than they perhaps deserve. Needless to say, they'll fall more if they continue to play like they have of late.
(Meanwhile, Texas will play Oklahoma next week in the Red River Rivalry, with its own rating having leaped to fifth overall thanks to three resounding wins, an ultracompetitive loss to the No. 1 overall team and a loss to Texas Tech that SP+ viewed as one of the least-likely losses of the season. It might look weird, but the Horns have been phenomenal on paper.)
Conference rankings
1. SEC: 14.9 average SP+ (34.9 average offensive SP+, 20.2 average defensive SP+)
2. Big 12: 13.8 average (35.6 offense, 21.8 defense)
3. Big Ten: 11.5 average (31.0 offense, 19.5 defense)
4. Pac-12: 6.6 average (31.9 offense, 25.4 defense)
5. ACC: 4.4 average (30.3 offense, 25.8 defense)
6. AAC: 2.5 average (28.7 offense, 26.2 defense)
7. Sun Belt: -0.4 average (26.7 offense, 27.0 defense)
8. Conference USA: -9.1 average (25.2 offense, 34.3 defense)
9. Mountain West: -11.9 average (19.1 offense, 31.0 defense)
10. MAC: -12.1 average (23.1 offense, 35.1 defense)
There were no changes in the overall hierarchy, but the Sun Belt's average rose by 2.9 points per team, while the MWC's dropped by 1.8. In terms of divisions, the Sun Belt East (2.6 average) now grades out better than the ACC Coastal (1.2). (Overall, the ACC's average is closer to the Sun Belt's than the Big Ten's.) Meanwhile, the dreadful MAC East (-15.4 average) is the only division worse than the MWC Mountain (-11.4) and MWC West (-12.5).
