Tuesday, December 2, 2008

More Analysis of Texas-Oklahoma

Some very good comments from the helpful folks at 2p2 have led to a further examination of the Texas-Oklahoma situation.
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responding to:
If two teams have the same schedule, except they play each other for one game, and have the same record, the team that is "better" will be ranked below the worse team, simply because they don't play themselves. Seems kinda silly IMO, although I guess they did have a more "impressive" schedule.

answer:
The power rankings I used for Texas and Oklahoma in creating spreads is less than half a point separate.
Let's actually look at that game.
A #5 team would be +4 on a neutral field against Texas and should win 41.18% of the time.
A #5 team would be +4.5 on a neutral field against Oklahoma and should win 39.59% of the time.

So, your complaint would be about a .0159 difference in the BAW5 ranking. That is pretty big, but does not make up the whole .054 difference.

However, I should state that the difference between the two teams is very, very small. If this were a poll, it would be within the margin of error. For instance, the brute method of rounding projected spreads to every half point and using a smoothed spread to win-pct conversion introduces plenty of small errors.
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responding to:
I'm assuming the biggest difference is Missouri for Texas. What is the difference between Missouri and the next best non-common team Oklahoma played?

answer:
nah... the biggest difference is Texas Tech at home versus Texas Tech on the road

The HFA for these three teams is very large, so it plays a bigger difference than your casual fan would ever expect.
A #5 team with Oklahoma's HFA against Texas Tech would be -5.5 and expected to win 66.86% of the time.
A #5 team playing at Texas Tech would be +5 and only expected to win 35.59% of the time.
The difference is 0.3127, which towers over the 0.054 difference between Texas and Oklahoma.

FWIW, TCU is considered a tougher game than Mizzou at home. Mizzou is about .02 tougher than Cincinnati.
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responding to:
Correct me if I've wrong, but margin of victory is not factored into your output, but it is factored into your input. Thus, isn't Team A punished for pummeling teams because now their opponents have relatively lower Massey Comparison ratings (since most systems use MOV)? When you analyze how a top 5 team would perform against Team A's schedule it will now have a higher expected win total than if Team A had won all its games by a small margin?

Maybe I'm interpreting your system incorrectly. Even if that's not the case, I still think that MOV should play a role in the evaluation of teams. IMO Oklahoma's superior MOV in games against tougher opponents makes up for Texas having a relatively small advantage in BAM5.

answer:
yep, MOV has some role in the input.
I'm taking the massey combined rankings. Massey combined works by taking every poll out there with a legitimate method and weighing them together. For the most part, those polls are just wins and losses. However, a significant portion do incorporate MOV. Some even do drive efficiency or adjusted yards per play. Massey takes all of that and turns it into one combined ranking based on a consensus. A team would be 'punished' in a sense for destroying its opponents. The question is how much is that punishment and how much is it just reflecting that the opponent is weaker.

Oklahoma's case is MOV and my BAW rankings do back that up.
I went through and looked at what the expected point differential would be based on my methodology. Oklahoma would be expected to be up 199 points right now. Texas would be expected to be up 201 points right now. In actuality, I think it's 342 versus 304. Oklahoma is doing a FG better per game than Texas is versus expectations.
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1 comment:

Justin said...
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