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## The SEC and Big XII schedules are weird. The ACC’s slightly less so.

Posted by Doug on October 2, 2008

Yesterday Chase proposed a fairly major modification of the Adjusted Yards Per Attempt statistic that is the basis of his various passer rating formulae. In particular, he is proposing to increase the TD bonus from 10 yards to 17 or 18. I intend to argue in a future post that that number should be 20.

But that has to wait, because I am fascinated by a bizarre and obscure topic that no one else cares about, and I have to tell you all about it....

I'm sure there are bigger schedule-o-philes in the world than me, but I'm generally in tune with how sports schedules operate and what their consequences are. So I'm ashamed to say that the SEC and Big XII have existed in their current two-division, 12-team format for more than a decade now, but I've never sat down and worked out how the interdivisional schedules work in those two conferences.

I did so this week, and was surprised by what I found. The main point of this post is to try to find people who have explanations for why these schedules are structured as they are.

For the sake of definiteness, I'll talk about the 2008 Big XII regular season schedule. With the appropriate mapping of teams to teams, the 2008 SEC schedule is identical. The 2008 ACC schedule is different; I'll talk about that later. I haven't checked earlier years to see if the 2008 system is the standard or if the schedule structure varies.

The Basics

The Big XII is divided into two divisions (called North and South) of six teams each. Each team plays every team in its own division once. Each team plays three of the six teams in the other division. For the purposes of this post, the intradivisional games are uninteresting. What I'm interested in is how to decide which three North teams a given South team will play.

Three natural ways to construct the schedule

1. All members of the Big XII North hold hands and stand in a circle. All members of the South hold hands and stand in a circle just inside the North circle. Align the circles so that a South team is standing directly inside each North team. That's your first opponent. Now leave the North circle stationary and rotate the inner circle 60 degrees. You're now standing next to your second opponent. Rotate again and you've got your third opponent. Done.

2. In each division, form two subdivisions of three teams each. South A plays North A and South B plays North B.

3. In each division, form three subdivisions of two teams each. South A plays North A, South B plays North B, and South C plays North C. Now everyone needs one more game. So each South A team could play a North B team, each South B team could play a North C team, and each South C team could play a North A team.

These three methods popped into my head immediately and, even after some thought, no other method did. So before I looked at the schedule, I figured it had to be one of these three.

It wasn't.

Here's how they do it

They divide the South into three subdivisions and the North into two. In the South, here is what we have:

Big XII South Division A: OU, Texas Tech
Big XII South Division B: Oklahoma State
Big XII South Division C: Texas, Baylor, Texas A&M

In the North, we have:

Big XII North Division A: Kansas, K-State, Nebraska
Big XII North Division B: Mizzou, Iowa State, Colorado

And the schedule is constructed as follows:

Everyone in South A plays everyone in North A
Everyone in South B plays everyone in North B
Everyone in South C plays one team from North A and two teams from North B

This strikes me as much more complicated than the three methods I outlined above, but what I find particularly strange is that it's not symmetric. The North and the South are not interchangeable. I guess there's no reason why they have to be, but don't humans naturally tend toward symmetry in their designs when possible?

The ACC's schedule is symmetric. Before I tell you about it, I'll go on a mini-rant about The New ACC in general: IF I LIVE TO BE A THOUSAND YEARS OLD, I WILL STILL NOT BE ABLE TO FIGURE OUT WHO IS IN WHICH DIVISION IN THE ACC. It drives me crazy. Part of the problem is a certain interchangeability and generic-ness of the teams themselves. But there also doesn't seem to be any geographical or other basis for remembering what's what. The divisions are named the Atlantic and the Coastal. How is that supposed to help me?

The ACC essentially breaks it down into two two-team subdivisions and two one-team subdivisions in each division. I'll call the one-team subdivisions A and D and the two-team subdivisions B and C. With that, A plays A and B, D plays C and D. Then each team in B plays one team from B and one team from C. There may be a better way to visualize that, but it's not equivalent to any of the three methods I outlined at the beginning of the post.

1. Does anyone know anything about the history of these schedule structures? Have they always been like this or do they vary?

2. Assuming they've always been like this, how did they decide on these methods? The Big XII / SEC schedule strikes me as something that was either the result of a whole lot of thought or no thought at all. There may well be a good reason for it and I'm just not seeing it. If so, what's the reason? If not, do you think they just started pairing teams up willy-nilly and this is what they ended up with?

3. Also assuming they've always done this, does anyone know how the teams rotate through the various subdivisions from year to year?

4. My interest in this investigation comes from issues of fairness. Among these methods, which one maximizes the probability of the best team winning the conference? Or does it not make any difference? That question is pretty high on my long-term to-do list right now.

5. I have ruled out the following as explanations for the weirdness of these schedule structures:

5a. The fact that it is necessary to alternate home games. I'm pretty sure the Big XII schedule stays the same for two years at a time, with only the locations alternating. This could be done with any schedule structure.

5b. The fact that certain interdivisional games have to take place every year. I believe Tennessee and Alabama play every year despite being in opposite divisions. Maybe Georgia and Auburn do too. Florida State and Miami? Anyway, I don't see how this explains the structure. Regardless of the structure, a rearrangement of the teams within the structure could ensure that Tennessee and Alabama are always paired up.

5c. The fact that it is desirable (I assume) for every team to play every other team an equal number of times in the long run and/or for the mixture of visiting opponents in every city to be kept "fresh" in some sense. Again, these goals could easily be accomplished by an appropriate year-to-year shuffling of teams, regardless of the schedule structure.