Bill Connelly, ESPN Staff WriterSep 24, 2023, 06:30 PM
Remember when we entered the 2023 college football season thinking we had a "top four and everyone else" situation? That is no longer the case. Four weeks into the season, we officially have a battle royale for the top spot.
In the final SP+ preseason projections, the top four teams (Georgia, Ohio State, Michigan and Alabama) were pretty well separated from the pack. Only 1.2 points separated No. 1 from No. 4, but 5.3 separated No. 4 from No. 5. Now? We have only 5.9 points separating No. 1 from No. 10. Michigan is your new No. 1 -- it's the fourth time the No. 1 ranking has changed hands in four weeks -- but with the weight of opponent and conference adjustments kicking in far more after four games, the Pac-12 as a whole has made a pretty serious move up the charts. The top three of Michigan, Georgia and Ohio State remains familiar, but three Pac-12 teams and two Big 12 teams are within reach of the No. 1 spot. This season could get very, very interesting in the coming weeks.
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.
Here are the full rankings:
This week's movers
Let's take a look at the teams that saw the biggest change in their overall ratings. (Note: We're looking at ratings, not rankings.)
MOVING UP
Here are the 10 teams that saw their ratings rise the most this week:
Georgia Southern: up 5.4 points (from 91st to 78th)
Jacksonville State: up 4.6 points (from 111th to 95th)
Miami (Ohio): up 4.2 points (from 93rd to 82nd)
Liberty: up 4.2 points (from 70th to 51st)
New Mexico: up 3.2 points (from 129th to 117th)
Georgia State: up 3.2 points (from 79th to 72nd)
UNLV: up 3.2 points (from 99th to 89th)
Louisiana: up 3.0 points (from 74th to 67th)
Air Force: up 3.0 points (from 59th to 42nd)
Washington State: up 2.8 points (from 38th to 28th)
All but one of those teams are from the Group of 5, which is fun -- the Sun Belt is separating itself from the other G5 conferences, and the Mountain West just passed the AAC in terms of conference averages -- but probably isn't what you're looking for here. So here are the top five risers within power conferences:
Washington State: up 2.8 points (from 38th to 28th)
Kansas: up 2.8 points (from 55th to 40th)
Miami: up 2.5 points (from 22nd to 13th)
Duke: up 2.3 points (from 32nd to 24th)
Georgia Tech: up 2.2 points (from 80th to 74th)
Because quite a few other Pac-12 teams also rose this week, Washington State is still looking up at half of its conference in the rankings. But wow, have the Cougars steadily risen this season. Meanwhile, Kansas and Duke are both 4-0 for the first time since 1952, and both are in the SP+ top 40. Considering where both teams were at the end of the 2021 season, that's an absolute miracle; Lance Leipold and Mike Elko deserve all the praise they get. (The Jayhawks and Blue Devils have never both been 5-0, by the way. They'll have to beat Texas and Notre Dame, respectively, to make that happen next week.)
MOVING DOWN
Here are the 10 teams whose ratings fell the most:
Iowa: down 6.7 points (from 28th to 39th)
Notre Dame: down 6.6 points (from fourth to 11th)
Auburn: down 6.5 points (from 23rd to 35th)
Ole Miss: down 5.6 points (from 14th to 22nd)
Baylor: down 5.3 points (from 49th to 66th)
Minnesota: down 5.2 points (from 42nd to 54th)
Mississippi State: down 5.0 points (from 39th to 45th)
Ohio State: down 4.9 points (from first to third)
FIU: down 4.9 points (from 106th to 124th)
LSU: down 4.9 points (from 15th to 21st)
Plenty of power conference representation here, huh? Iowa's pathetic offense, combined with a defense that is clearly good but probably isn't the best in the country, has become an anchor (well, more of an anchor than usual) for the Hawkeyes, and plenty of other Big Ten and SEC teams dropped as well.
Maybe the most interesting thing here is that both Notre Dame and Ohio State dropped quite a bit after Saturday night's gripping rock fight. Both teams were hurt by the increased weight of opponent adjustments, and since both teams' offensive ratings were driven by impressive explosiveness numbers heading into Week 4, a complete lack of explosiveness -- the 17-14 Ohio State win saw just three combined gains of more than 25 yards -- dragged the teams' offensive ratings down more than their defensive ratings rose. A weird quirk, to be sure, but this is the point in the season where weird quirks appear.
Conference rankings
Here are the FBS' 10 conferences, ranked by average SP+:
1. SEC: 12.7 average SP+ rating (33.5 offense, 20.9 defense)
2. Pac-12: 10.0 average (33.4 offense, 23.5 defense)
3. Big 12: 8.7 average (31.1 offense, 22.5 defense)
4. Big Ten: 6.9 average (26.4 offense, 19.5 defense)
5. ACC: 6.4 average (29.8 offense, 23.4 defense)
6. Sun Belt: -5.3 average (24.0 offense, 29.2 defense)
7. Mountain West: -8.2 average (22.1 offense, 30.3 defense)
8. AAC: -8.5 average (23.1 offense, 31.5 defense)
9. Conference USA: -12.4 average (19.1 offense, 31.4 defense)
10. MAC: -14.5 average (17.9 offense, 32.3 defense)
The averages for both the SEC and Big Ten slipped by 2.7 points per team this week, while the Sun Belt (+1.3 per team) and Mountain West (+1.0) both enjoyed solid gains, as did the elite portion of the Pac-12: Washington jumped from eighth to fourth, and Oregon jumped from 11th to sixth.
The SEC still leads the way overall, mainly because its worst teams are far better than that of the other power conferences, but having three of the top six teams and seven of the top 28 is an obvious boon for a Pac-12 Conference that is trying as hard as it can to go out on top.
