Points Per Pass Metric, Results Through Week 13

My passing offense metric, updated with last week's results. See below an explanation of the statistical details:  It's the same text I've posted in previous weeks.  The only difference is the minimum cutoff for making the list is 130 pass attempts.

Our man Tony Romo switched places with Favre after last week's game.  They've been mirror images of each other the last few weeks, having nearly (and eerily) identical scores; last week Favre jumped ahead slightly, but after last week's head-to-head matchup, Romo pulled ahead--and would have been even higher were it not for Owens' bizarre endzone lateral to Al Harris for an interception.

While watching Monday night, Brady's mediocre game confirmed what I had suspected all along--that his level of performance is simply not sustainable.  Quite unlike his mythological reputation as the most clutch QB ever, his points per pass metric have been decent, but really nothing exceptional prior to this season, with the exception of 2005.  He has shown steady progress throughout his career, although last year was a setback, but I'm not sure he's all that much better than previous years.  What has changed this year is his receiving corps.  He had better hope that Moss and Stallworth, who have a history of being plagued with injuries, stay healthy throughout the playoffs, otherwise the Patriots could find themselves in the embarrassing situation of going undefeated in the regular season and losing in the playoffs.

Here's the intro I've posted on previous weeks:

I've been using a passing offense metric for many years now to gauge how well a QB is doing.  Inspired by baseball SABRmetrician Bill James, I performed linear regressions of NFL statistics and concluded from a big picture point of view, only two statistics mattered:  Yards gained from scrimmage, and turnovers.  The best fit to matching points scored came when assuming the following coefficients:

Ten yards gained from scrimmage = +1.0 points; and
One turnover lost = -6.0 points.

Simply put, teams that score points rack up yardage and don't commit turnovers.  Note how powerful turnovers are:  A team can, for example, gain 55 yards of offense, but if they turn it over the next play, they actually ended up hurting their team.

With that in mind, I created the points per pass metric, which calculates the effectiveness of quarterbacks.  The above two coefficients are used to determine, on average, how many points a quarterback (and his offensive teammates, since everyone else contributes to his success or failure) creates with each passing attempt.  It takes the simple yards per attempt metric we're all familiar with, adjusts it for sacks, and further adjusts it for turnovers.  One interception equates to minus six points; one fumble equates to minus three points.  I treat fumbles as half a turnover, since there's essentially a 50/50 chance of recovering or losing a fumble.  The results will probably be unsurprising for the most part, but sometimes they can appear odd.  One of the things that may cause these oddities are fumbles.  Most people, when looking over a QB's stat line, don't think about fumbles; they just look at yardage, attempts, touchdowns, interceptions, and maybe sacks.  But fumbles are very important, since they are essentially half a turnover.

Brady, NE                                        0.76
Garrard, Jax                                    0.64
Garcia, TB                                       0.60
Romo, Dal                                       0.56
Favre, GB                                        0.55
Schaub, Hou                                   0.51
Anderson, Cle                                 0.49
Manning, Ind                                   0.48
Hasselbeck, Sea                             0.47
McNabb, Phi                                    0.46
Cutler, Den                                     0.44
Palmer, Cin                                     0.44
Warner, Ari                                     0.43
Brees, NO                                       0.41
Harrington, Atl                                0.41
Edwards, Buf                                  0.37
Roethlisberger, Pit                          0.37
Kitna, Det                                       0.36
Pennington, NYJ                              0.36
Campbell, Was                               0.35
Rivers, SD                                       0.34
Boller, Bal                                       0.33
Jackson, Min                                   0.33
Losman, Buf                                   0.31
Green, Mia                                      0.31
Lemon, Mia                                     0.31
Culpepper, Oak                               0.30
Manning, NYG                                 0.29
Bulger, StL                                      0.29
Testaverde, Car                              0.29
Griese, Chi                                      0.27
Huard, KC                                       0.26
McNair, Bal                                      0.25
Clements, NYJ                                 0.25
Grossman, Chi                                0.25
Young, Ten                                     0.24
Smith, SF                                        0.18
Carr, Car                                         0.16
Frerotte, StL                                   0.10
Dilfer, SF                                         0.03
McCown, Oak                                 0.01