QB Wins Added 1

In this series of posts I'm going to build a better quarterback rating system. The system will be try to isolate the passing stats that the QB alone is primarily accountable for. The stats will be efficiency stats in that they are in terms of attempts. The system will also attempt to exclude redundancy stats.

The official Passer Rating system includes co-dependent factors such as TDs, interceptions, and completion percentage. But an accurate QB will tend to have both a high completion rate and high TDs. The passer rating, therefore, double counts accuracy. Further, a QB's passing TDs may be due to his defense's ability to get the ball turned over to him in his oppenents' territory, or due to an effective running game, as much as due to his own ability. The goal is to isolate what the QB is truly responsible for and filter out what the QB does not control.

The system will include completion percentage, interceptions per attempt, and sack yards per pass attempt. Although interceptions and sacks are not solely attributable to the QB, the stats imply that the QB is overwhelmingly responsible for them. Take the case of McNair in Baltimore. After replacing Kyle Boller, Baltimore went from one of the league's worst sack rates to one of the best. The rest of the offense, including the offensive line, was completely identical.

Each stat in the system will be translated into team wins by the efficiency win model previously established. In the first post we'll rank quarterbacks in terms of their 2006 regulare season completion percentage. We'll compute how many percentage points above or below average each QB was last year. All other factors being equal, every additional point of completion percentage brings an extra 0.18 wins to a team on average. Therefore we can compute how many wins each QB contributed to his team by his completion percentage alone.

(Only QBs with more than 100 attempts are considered.)

Player	Comp Pct	Pct > Avg	Wins Added
David Carr	68.3	8.89	1.60
Tony Romo	65.3	5.89	1.06
Peyton Manning	65.0	5.59	1.01
Chad Pennington	64.5	5.09	0.92
Charlie Frye	64.3	4.89	0.88
Kurt Warner	64.3	4.89	0.88
Drew Brees	64.3	4.89	0.88
Steve McNair	63.0	3.59	0.65
Marc Bulger	62.9	3.49	0.63
J.P. Losman	62.5	3.09	0.56
Jon Kitna	62.4	2.99	0.54
Carson Palmer	62.3	2.89	0.52
Mark Brunell	62.3	2.89	0.52
Tom Brady	61.8	2.39	0.43
Philip Rivers	61.7	2.29	0.41
Jeff Garcia	61.7	2.29	0.41
Brad Johnson	61.5	2.09	0.38
Trent Green	61.1	1.69	0.30
Jake Delhomme	61.0	1.59	0.29
Damon Huard	60.7	1.29	0.23
Daunte Culpepper	60.4	0.99	0.18
Tim Rattay	60.4	0.99	0.18
David Garrard	60.2	0.79	0.14
Ben Roethlisberger	59.7	0.29	0.05
Jay Cutler	59.1	-0.31	-0.06
Byron Leftwich	59.0	-0.41	-0.07
Seneca Wallace	58.2	-1.21	-0.22
Alex Smith	58.1	-1.31	-0.24
Eli Manning	57.7	-1.71	-0.31
Joey Harrington	57.5	-1.91	-0.34
Aaron Brooks	57.3	-2.11	-0.38
Donovan McNabb	57.0	-2.41	-0.43
Matt Leinart	56.8	-2.61	-0.47
Matt Hasselbeck	56.6	-2.81	-0.51
Derek Anderson	56.4	-3.01	-0.54
Brett Favre	56.0	-3.41	-0.61
Jake Plummer	55.2	-4.21	-0.76
Chris Simms	54.7	-4.71	-0.85
Rex Grossman	54.6	-4.81	-0.87
Bruce Gradkowski	54.0	-5.41	-0.97
Andrew Walter	53.3	-6.11	-1.10
Drew Bledsoe	53.3	-6.11	-1.10
Jason Campbell	53.1	-6.31	-1.14
Michael Vick	52.6	-6.81	-1.23
Vince Young	51.5	-7.91	-1.42
Average	59.4

In the next post, I examine interception rate. Then in the third part of this this article, I'll look at sack yardage rate. Finally, I'll sum the wins added for each QB to produce a more valid passer rating system.