College football's Week 4 SP+ rankings takeaways - ESPN

Last week, I made a pretty big deal out of the fact that the top five college football teams in the country, per SP+, were all within 1.8 points of each other. This week, they're within 1.3.

We've technically got a new No. 1 team — Texas eases into the top spot after a lopsided win over ULM — but congestion remains the story. SP+ is pretty confident that it knows who the five best teams in the country are, and it seems pretty clear on No. 6-11 too. There's interesting stratification among the top tiers, but at this point one thing is certain: It's Ohio State versus the SEC when it comes to the top of the college football hierarchy.

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.

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.)

UConn: up 5.8 adjusted points per game (ranking rose from 116th to 97th)

Virginia: up 4.8 points (from 79th to 62nd)

Cincinnati: up 4.3 points (from 62nd to 50th)

South Alabama: up 4.2 points (from 84th to 71st)

Duke: up 4.2 points (from 52nd to 34th)

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