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# Better Know a Computer: Massey

Here's a look at how the Massey ratings work.  I should feel wiser from learning something, but instead I feel like my brain has been laid low by an influx of numbers and equations that I will spend at least a week purging from my mind.

Game Outcome Function (No longer used)

Or GOF for short.  The GOF takes the score of every game and calculates the statistical probability that, if the game were played again, the outcome would be the same.  A law of dimishing returns safeguards the system from teams that run up the score and keep the system BCS worthy. From the GOF is calculated what is called...

The Power Rating

This is a purely predictive rating that comes from the GOF formula, but that's not all that goes into the formula.  Next, the Power Rating goes through what is called...

The Bayesian Win-Loss Correction

Though I don't exactly understand how a Bayesian Correction works, trips to Wikipedia were wholly unhelpful, I know that this adds a retrodictive element to the ranking so together the rating system would be called a mixed system, because it factors in both predictive and retrodictive elements.

Postprocessing

Next he factors in Offensive and Defensive Power ratings, which are formed by measuring points scored and allowed taking into account the Offensive and Defensive Power ratings of the opposing teams, Conference ratings, measuring the success of the team's conference against non-conference opponents, and...

Strength of Schedule

Massey calculates schedule strength by taking the rating of each opponent (pre-adjustment for SOS) and compares each one to the team in question's rating.  From this he adds to each opponents rating a probability that the team in question would win (thus an opponent with exactly the same rating would have .5 added to it's rating for the sake of calculating SOS).  After that home field advantage is factored in and the opponents' ratings are averaged out, hence strength of schedule.

And there you have it.

Current Massey Ratings

1.  Michigan
2.  Ohio State
3.  Louisville
4.  Cal
5.  Florida
6.  Auburn
7.  Notre Dame
8.  USC
9.  Rutgers
10. Arkansas
11. Tennessee
12. Wisconsin
13. Boise State
14. LSU
15. Texas
1. WVA
2. Oregon
3. Oregon State
4. Georgia Tech
5. Oklahoma
So we're behind two two-loss SEC teams, an undefeated WAC team, and all the other undefeated and one-loss teams.  Awesome.

Our schedule is ranked 48th

--AR--