130-team S&P+ rankings: The SEC and Big 12 have been the best conferences

Below are the new S&P+ rankings after college football’s Week 9.

Good predictive ratings are not résumé ratings, and they don’t give you bonus points for wins and losses. They simply compare expected output to actual output and adjust accordingly. That’s how a given team can win but plummet or lose and move up.

Through nine weeks, the S&P+ rankings are performing well, hitting 55 percent against the spread and 53 percent on the over/under point totals for the year.

As you would hope, the absolute error — the average size of miss between projection and reality — has settled into a healthy area as well.

If you’re interested in a decent résumé ranking of sorts, I encourage you to visit this post on strength of schedule. I created a Resume S&P+ ranking and will be updating it on Mondays throughout the rest of the season.

Below, however, are the predictive ratings, the actual S&P+.

(You can find full unit rankings, plus a yearly archive, at Football Outsiders. The offense and defense pages are updated by Monday at the latest.)

The preseason S&P+ projections were pretty accurate overall — of the current teams in the top 15, 14 began the season projected 25th or better. Granted, part of that is impacted by the fact that those projections are still included in S&P+, but in-season data makes up a vast majority of the formula now, and it’s still pretty stable at the top.

Arizona, however, has had what you might call a rather unstable season. To put it lightly. The Wildcats began the season projected 32nd, fell all the way to 109th within two weeks, rebounded to 55th, hit 87th with a thud two weeks ago, and just rebounded 12 spots — their seventh time moving either up or down by double digits — following their out-of-nowhere blowout of Oregon. Considering the season began with division title aspirations, it’s safe to say that this season will have been a disappointment even if UA rebounds to bowl eligibility. But what a ride it’s been regardless.

Only one current top-15 team began the season outside of the top 25: Jeff Tedford’s Fresno State Bulldogs. They began 42nd and stood at 38th after losing a tossup game to Minnesota in Week 2. Since then:

Hawaii was the first team all season to average better than 5.3 yards per play against Fresno State (national average is typically in the 5.7 or 5.8 range). And when a team does move the ball a bit, Tedford and offensive coordinator Kalen DeBoer release the hounds on offense.

Obviously the race for the Group of Five’s New Years Six bowl bid goes through UCF — until the Knights lose, FS probably doesn’t have a chance because of the Minnesota loss — but Fresno has been absolutely ridiculous since the Minnesota game, and it was decent against the Gophers, too.

When Baylor headed to Morgantown for a Thursday night battle with WVU, the Bears had, per S&P+, a 61 percent chance of reaching bowl eligibility. Safe to say, those odds have sunk dramatically, not only because they lost to the Mountaineers, but because they lost badly and damn near fell out of the top 80 in the process.

A quick reminder: as non-conference play ends and conference play begins, the scoring margins tend to get closer on average. As a result, the overall spread of S&P+ ratings — which is distributed along the bell curve for scoring margins — tends to get smaller each week, too. That explains why the top conferences’ averages continue to fall while the bottom conferences’ averages all continue to rise.

Margins aside, though, there were no changes to this week’s conference rankings. The Big 12’s lead over the Big Ten for the No. 2 spot basically vanished, but it remains No. 2 at the moment, quite the plot twist from the previous couple of seasons. Its glorious, grinding conference title race might preclude it from having a national title contender (though OU’s CFP odds are still solid), but despite far-worse-than-normal Kansas State and TCU teams, this is the deepest the conference has been in quite some time, with seven of 10 teams in the top 50. We’ll see if it can hold off the Big Ten, but it’s looking like it will finish third at worst.

When I get the chance (so, maybe in the offseason), I will update previous years of S&P+ rankings to reflect these formula changes, too.

Basically, I’ve added a step to the the rankings process: after the rankings are determined, I go back and project previous games based on those ratings, and I adjust the ratings based on how much the ratings fit (or don’t fit) those results.

The adjustment isn’t enormous, and it diminishes dramatically as the season unfolds.

Testing this process for past seasons improved performance against the spread a little and, more importantly, decreased absolute error (the difference between projections and reality) quite a bit. I wouldn’t have made the move if it didn’t appear to improve performance.