College football's post-Week 5 SP+ rankings

It seems like it's a pretty good year to have a bigger College Football Playoff, as SP+ sure can't decide who the best team is.

For the third straight week, the No. 1 spot in the SP+ rankings changed: Ohio State retakes the lead after previously top-ranked Texas struggled more than expected against Mississippi State. And with Georgia slipping once again after Saturday night's devastating loss to Alabama, Tennessee eases into the top five as well.

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.

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 after playing an FBS opponent this week:

Navy: up 6.7 adjusted points per game (from 83rd to 68th in SP+)
UConn: up 6.1 points (97th to 81st)
James Madison: up 5.1 points (57th to 33rd)
Army: up 4.7 points (78th to 70th)
UMass: up 4.3 points (126th to 122nd)
Wyoming: up 4.2 points (124th to 119th)
UNLV: up 3.9 points (65th to 54th)
Charlotte: up 3.5 points (127th to 125th)
Arizona : up 3.4 points (52nd to 35th)

Colorado: up 3.2 points (66th to 60th)

This list has a heavy Group of 5 presence, but there are quite a few noteworthy teams. Both Army and Navy not only remained unbeaten this week, but did so with style, beating Temple and UAB by a combined 51 points. James Madison, meanwhile, throttled poor Ball State to jump to 33rd, the current highest ranking for a G5 team, and SP+ took a big step toward believing in UNLV. Despite this week's off-the-field drama, the Rebels destroyed Fresno State in what was supposed to be a pretty tight, competitive game.

Oh yeah, and break up the UConn Huskies! After a poor Week 1 performance dropped Jim Mora's squad to 132nd overall, UConn has overachieved dramatically against projections each week since and now ranks ahead of four power conference teams.

Moving down

Here are the 10 teams whose ratings fell the most:

Georgia: down 4.6 points (fifth to seventh)
Fresno State: down 4.5 points (67th to 80th)
Oklahoma State: down 4.5 points (25th to 39th)
Ole Miss: down 4.2 points (no rankings change)
Ball State: down 3.7 points (123rd to 131st)
Buffalo: down 3.7 points (98th to 112th)
South Alabama: down 3.6 points ( 71st to 82nd)
Utah: down 3.3 points (13th to 25th)
Miami: down 3.3 points (seventh to 11th)
USF: down 2.7 points (90th to 98th)

Even with its rousing second-half comeback, Georgia's performance against Alabama was disappointing, especially on defense. The Dawgs' defensive SP+ rating increased (meaning: it regressed) by 4.7 points after Bama's 547-yard, 41-point performance -- which also bumped the Crimson Tide to No. 1 in offensive SP+ -- and dropped them to seventh overall. And they still have three more games against teams ranked above them. That includes Ole Miss, whose rating also fell following an upset loss to Kentucky. Honestly, I expected a bit more of a fall for the Rebels.

Conference rankings

Here are the FBS' 10 conferences, ranked by average SP+:

1. SEC: 16.7 average adjusted PPG (36.2 offense, 19.7 defense)
2. Big Ten: 10.0 average (28.6 offense, 18.7 defense)
3. ACC: 8.0 average (31.4 offense, 23.6 defense)
4. Big 12: 7.5 average (32.1 offense, 24.7 defense)
5. Sun Belt: -6.9 average (25.7 offense, 32.5 defense)
6. AAC: -7.6 average (24.5 offense, 32.1 defense)
7. Mountain West: -7.8 average (23.8 offense, 31.5 defense)
8. MAC: -13.8 average (17.0 offense, 30.7 defense)
9. Conference USA: -14.0 average (19.8 offense, 33.6 defense)

We had some movement at the G5 level: The AAC inched ahead of the MWC, thanks primarily to the work of Army and Navy. (Tulane, North Texas and FAU also rose a solid amount this week.) Meanwhile, the MAC's average rating fell more than anyone's this week, in part because both Buffalo and Ball State plummeted; the conference now houses the second-, third- and fourth-worst teams in this week's ratings.

SP+ projects the College Football Playoff

Here's what the new 12-team CFP would look like based on updated SP+ projections (and how the results would shake out if every favorite won, which never actually happens).

First round

12 James Madison at 5 Alabama (Bama by 21.7)
11 Notre Dame at 6 Penn State (PSU by 7.0)
10 Missouri at 7 Tennessee (Vols by 6.6)
9 Ole Miss at 8 Oregon (Ducks by 0.2)

Quarterfinals

1 Texas vs. 8 Oregon (Texas by 4.6)
4 Iowa State vs. 5 Alabama (Bama by 14.5)
3 Miami vs. 6 Penn State (PSU by 4.7)
2 Ohio State vs. 7 Tennessee (Buckeyes by 4.1)

Semifinals

1 Texas vs. 5 Alabama (Texas by 0.1)
2 Ohio State vs. 6 Penn State (Buckeyes by 4.9)

Final

1 Texas vs. 2 Ohio State (Buckeyes by 1.5)

If you were to offer me nine one-score finishes in an 11-game playoff right now, I would happily accept it. I'd probably pay money for it, actually.