Strength of Schedule Revisited

In the previous discussion of schedule strength, I posed a system better than the one I was currently using, which was simply an average of opponents' team ratings. To recap this system:

Strength of Schedule
Rank all teams according to their Team Rating score.
Each opponent ranked in the top 10 is worth 3 points.
Each opponent ranked 11-30 is worth 2 points.
Each opponent ranked 31-70 is worth 1 point.
Each opponent ranked 71-100 is worth 0.5 points.
Each opponent ranked 101-120 is worth 0 points.
Each 1-AA opponent is worth 0 points.

In addition to this, teams get a bonus for playing away games. Specifically, +0.5 for playing an away game at a team in the top 70, and +0.25 for teams 71-100. Teams in the bottom 20 are so bad that playing them at home is not really a factor.

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In past years, I've noticed that sometimes schedule strength is dominated by one or two conferences. Looking over results from previous seasons, it seems clear that, on the conference level, schedule strength comes down to two factors. Average team rating of the conference, and the number of non-conference games played. The first element is blindingly obvious. The better your conference is, the tougher your schedule. The second part might not be so clear. As much as people like to look down on other conferences for their scheduling of cupcakes, when it comes down to it, there's not much variation between the level of inter-league competition (especially within the 6 BCS conferences). The key is the number of non-conference games played. Since any cupcake you schedule is unlikely to be better than the average team in your conference, playing more cupcakes can only reduce your overall schedule strength.

Let's take a look at schedule strength by conference for the 2008 season.

Strength of Schedule (Conference Averages)
	Rating	SoS (Rank)	SoS (Raw)
SEC	0.534	25.42	1.415
Big Ten	0.525	38.36	1.319
Big XII	0.519	36.17	1.329
Big East	0.499	55.13	1.215
Pac-10	0.492	15.40	1.522
ACC	0.487	59.58	1.191
Mtn West	0.485	50.89	1.236
MAC	0.445	98.08	0.941
CUSA	0.444	91.08	0.974
WAC	0.441	83.44	1.096
Sun Belt	0.410	109.75	0.823

Among the 6 BCS conferences, all except the Pac-10 and Big East play 4 non-conference games a season. So the among the ACC, Big Ten, Big XII, and SEC you'd expect that their average schedule strength would be reflected by the average team rating and that's exactly what we saw last season. Now, when the NCAA expanded the schedule to 12 games, the Pac-10 used the extra game to make a proper round-robin conference schedule. So while the other BCS schools were rushing to ink deals with the Towsons and Charleston Southerns of the world, Pac-10 teams added another Pac-10 team. Look at the table. The Pac-10 was, on average, the second worst BCS conference last season, but had the highest average SoS. Conversely, the Big East who play 5 games out of conference had an average SoS worse than the Mountain West!