College football SP+ rankings after Week 8: How the Big Ten's return shakes things up

Finally, the best team in the country has played a game.

Based on its preseason projections, Ohio State has continued to rank first in SP+ for two months, and the Buckeyes certainly looked the part in an easy win over Nebraska on Saturday. The rest of the Big Ten slate, however, packed some surprises. Michigan, Wisconsin and Northwestern all looked fantastic -- Northwestern was super-fast and explosive! Northwestern! -- while Maryland, Michigan State and others were ... not great.

Combine that with some surprising Mountain West debut performances, and you've got a lot of movement in this week's ratings. Even if No. 1 remained the same.

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. That is important to remember. 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 numbers.

This week's movers

The typical Week 8 doesn't usually feature a ton of movement in the rankings. Of course, the typical Week 8 doesn't include 24 teams making their season debuts.

Moving up

Ten teams moved up at least 10 spots in this week's rankings. Eight of them played their first game on Saturday.

  • San Jose State, up 27 spots from 106th to 79th

  • San Diego State, up 26 spots from 75th to 49th

  • Hawaii, up 26 spots from 98th to 72nd

  • Rutgers, up 26 spots from 109th to 83rd

  • Northwestern, up 24 spots from 54th to 30th

  • Nevada, up 19 spots from 107th to 88th

  • Boise State, up 15 spots from 35th to 20th

  • Purdue, up 12 spots from 48th to 36th

  • Liberty, up 12 spots from 55th to 43rd

  • UAB, up 10 spots from 50th to 40th

A jump this large can mean something sustainable. BYU, for instance, jumped from 53rd to 30th after one game, then kept right on rising into the top 10. Marshall jumped from 86th to 54th, and Liberty jumped from 110th to 91st, and both have continued to creep upward.

On the other hand, Georgia Tech made an immediate jump from 52nd to 38th and has since cratered back to 64th. Teams like Boston College and West Virginia made immediate jumps and have since been running in place. We'll see which of the above teams are able to sustain their first-week gains.

Moving down

If some teams are moving up, some must be moving down. Twelve teams dropped at least 10 spots in this week's rankings, but surprisingly, only five of them made their debuts in Week 8.

  • Air Force, down 21 spots from 59th to 80th

  • Minnesota, down 17 spots from 16th to 33rd

  • Kentucky, down 17 spots from 36th to 53rd

  • Maryland, down 15 spots from 84th to 99th

  • South Carolina, down 14 spots from 53rd to 67th

  • Georgia Southern, down 14 spots from 81st to 94th

  • Tennessee, down 13 spots from 37th to 50th

  • Florida State, down 13 spots from 64th to 77th

  • Wyoming, down 12 spots from 90th to 102nd

  • Nebraska, down 11 spots from 31st to 42nd

  • NC State, down 10 spots from 61st to 71st

  • Utah State, down 10 spots from 104th to 114th

In two games, Air Force has now overachieved projections by 35 points against Navy and underachieved them by 19 points against San Jose State. It appears playing one game per month isn't great for your consistency levels. Meanwhile, since leading Georgia at halftime, Tennessee has been outscored 109-24 in its last 10 quarters of play. Not great.

Why does SP+ hate Kansas State?

Kansas State dropped to 74th back in September following its first-game upset loss to Arkansas State. The Wildcats have since won four Big 12 games in a row but have crept up to only 66th overall. What gives? A few things, it seems.

First, the Arkansas State loss was really bad. My postgame win expectancy figure -- which takes the key predictive stats from a given game, tosses them into the air and says "Based on these stats, you could have expected to win this game X% of the time" -- was only 8% for KSU. This wasn't a random, unlucky upset (like what Penn State, with its 95% postgame win expectancy, suffered against Indiana this week); it was a "you were lucky to lose by only four" upset. That Arkansas State has lost three of its four other FBS games and fallen to 82nd in SP+ is an anchor that will continue to drag the Wildcats down.

The corresponding upset of Oklahoma didn't prove a huge rebound. KSU upset the top-10-at-the-time Sooners, 38-35, in its first game post-ASU. (What a strange season this has already been.) But OU held a major success rate/efficiency advantage, and SP+ saw turnovers luck as a major force in the victory -- KSU recovered two of the game's three fumbles, and while each team defensed five passes (INTs plus breakups), the Wildcats finished with three INTs to OU's zero, an unlikely combination. Postgame win expectancy for KSU in that one: only 36%.

KSU then beat mediocre-at-best teams by margins that suggest above-average-at-best quality -- 76% win expectancy against No. 86 Texas Tech, 53% over No. 51 TCU -- and only got so much credit this week for manhandling dreadful, 119th-ranked Kansas. Accordingly, the Wildcats have risen only a bit.

This is not newfound territory for KSU fans. A nascent version of SP+ was incredibly unimpressed with the 2011 Wildcats team that seemed to win every game by three points while getting outgained by 200 yards (only a slight exaggeration) before coming around on Bill Snyder's 2012 and 2013 teams. Chris Klieman has worked a bit of Snyder-like magic in his brief KSU tenure, going 5-2 in one-score games in Big 12 play (and strangely only 1-2 in nonconference). But each of their last five opponents is better than TCU, Texas Tech or Kansas. They'll probably have to improve a decent amount on paper to keep their Big 12 lead.