Some thoughts on/analysis of SEC strength of schedule numbers (long)

I've been thinking a lot about strength of schedule in this new era of college football (between the 12-team playoff and expanded conferences). There has been a lot of conversation around tRant about whether we should schedule big-name OOC opponents, and rightfully so (IMO) given how the past few years have gone.

One thing I haven't seen discussed a ton is how the strength of schedule within SEC play affects things. It makes sense. We consider the SEC to be the toughest conference in the country, and theoretically there are no "easy" SEC schedules. And historically, the schedule has been fairly static anyway with the old division system.

This year, though, there is a dramatic amount of variation among the strength of SEC schedules. What really made me start thinking about this was the fact that Texas went 7-1 in SEC play and will be #2 in the country going into the SECCG, despite not beating a single team currently ranked in the AP top 25. I wanted to pull some data together to see whether there was a correlation for SEC teams between success and strength of schedule.

The first thing I looked at was FPI. ESPN defines their FPI SOS rank as:

quote:

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Rank among all FBS teams of games already played schedule strength, from perspective of an average Top 25 team.

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Here are the SEC FPI SOS rankings, from strongest to weakest:



I don't know about y'all, but that's pretty striking to me. UGA has obviously performed well in spite of a brutal schedule but it looks like there's a pretty clear trend outside of that.

The next thing I wanted to see was whether I could actually plot win% against SOS. This gets rather tricky, because ESPN doesn't actually release the raw ratings for FPI SOS. They only release the rankings, as far as I can tell. Plotting anything against rankings can get dicey because for example there might be a much larger SOS difference from #1 to #4 than from #28 to #31.

I decided to build an SEC-only SOS metric based on Bill Connelly's SP+. For one thing, I generally like SP+ more than FPI anyway. And I was able to find quite a bit of information online that helped me replicate Connelly's win probability calculations, so I feel pretty confident about the numbers. By limiting it to SEC record and SEC-only SOS, we can look at how the "uncontrollable" part - SEC scheduling - might affect playoff hopes.

Here's what I came up with for strength of schedule:



This SOS metric is built up from the perspective of an average SEC team. The number represents the percentage of games an average SEC team would expect to lose. Higher number = harder schedule. Lower number = easier schedule.

Now let's look at that plotted against SEC record:



Again that is pretty striking to me. UGA seems to be overperforming and Auburn underperforming, but outside of that it looks like a pretty clear correlation.

If you're asking "what's the point?" I would say this: To me, it seems like we might be reaching a place in CFB where the real battle is getting the easiest possible schedule within a respectable conference. I didn't look at this in the context of CFP rankings yet (partially because that's harder and partially because the updated CFP rankings aren't out yet) but Oregon's FPI SOS ranking is #60. Notre Dame #57. Miami #55. SMU #75.

Looking at last week's CFP rankings, the toughest non-SEC SOS (according to FPI) in the entire top 25 was Ohio State at #26.. and they lost. Meanwhile Texas had the lowest SOS in the SEC and still managed to play a harder schedule than anyone else in the CFP top 10 sans Georgia. It just seems crazy to me, now that these conference schedules are all over the place post-expansion.

I don't know if anyone but me finds this stuff interesting, but thought I'd share anyhow.

(Edit: Fixed an error on one of the graphs.)
(Another edit: There’s an error in Tennessee’s SEC record in the table with FPI SOS rankings. Should be 6-2. I’ll fix it later.)