I recently put together a regression model to determine the factors that most drive the number of points a football team scores in any given game. It's a work in progress, but the factors I looked at were:
- Yards per attempt (Y/A)
- Interception %
- Yards/Rush
- Average Y/A yielded by opponent
- Average points yielded by opponent
Of the variables above, Y/A was, by the far, the strongest - followed by interception percentage. The other three were pretty close in importance.
You'll notice that a quarterback has a direct impact on 2 of the 5. With that in mind, I decided to create a quarterback rating system that looks primarily at the factors of Y/A and Int %. Further, because a quarterback's performance is obviously affected by their opponent, I added an element that accounts for the quality of the opponent's defense.
The formula for the rating, which I'm going to call the Opposition Adjusted Quarterback Rating (OA Quarterback Rating) until I can think of a cooler or funnier name.
The formula was basically:
- Y/A minus the opponent's average Y/A yielded (times a factor of 2.8 - as determined by the regression model) PLUS
- Int % minus the opponent's average Int % yielded (times a factor of -54 - again, as determined by the model)
A few notes. Because the season is only two weeks old, the "Opposition Stats" - the stats that were used for Y/A and Int % yielded - were from all of 2008 and the first two weeks of 2009. So, there is a margin of error there.
Also, when calculating the "Opposition Stats", the metrics from the game against the current quarterback was not counted. (I.e., if Jay Cutler is playing the Raiders, the "Opposition Stats" are from all of the games in 2008 and 2009 ecept for the one being played against the Raiders).
By the way, this is all a work in progress. As I get more information I will layer it in.
Below are the OA Quarterback Ratings for 2009 through week 2. See the 2008 rankings here.
You're killin' my boy, Brett! Who needs yards per attempt? :)
ReplyDeleteI love Brett - I just call them how I see them. Thanks for reading. By the way, I plotted my rating against points scored and it does pretty well. Maybe I should patent it.
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