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 160 pass attempts.

History continued to shadow both Brady and Romo with their performances last week, virtually eliminating their quests to overcome major historical hurdles.  Brady's value continues to free fall.  As late as last week, he looked to have a reasonable shot in overtaking Peyton Manning's 2004 season as the best ever of 0.73.  After last week, it's just a dream.

Similarly, Romo will almost certainly not improve on his value from last season.  I've mentioned my system predicted him to decline this year so many times that the details don't need to be repeated.  What I did do was run a hypothetical game next week, and see what kind of game would be needed to eclipse his 2006 value of 0.508.  Assuming he only plays the first half of tomorrow's game, and attempts half his average number of passes per game (17), he would need to throw for 187 yards with no sacks, interceptions or fumbles to do it.  That's an improbable 11 yards per attempt, with no mistakes to counteract it...it's not going to happen.

Interestingly, as Indianapolis is getting healthy, Peyton's value continues to climb, now back up to fourth place.  His game against San Diego was a major setback, but he and the Colts are rolling now.

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                                        0.66
Garrard, Jax                                    0.62
Garcia, TB                                        0.57
Manning, Ind                                   0.54
Favre, GB                                        0.52
Romo, Dal                                       0.49
Hasselbeck, Sea                             0.47
Brees, NO                                       0.47
McNabb, Phi                                    0.45
Schaub, Hou                                   0.45
Anderson, Cle                                 0.44
Cutler, Den                                     0.43
Palmer, Cin                                     0.43
Roethlisberger, Pit                          0.42
Harrington, Atl                                0.41
Warner, Ari                                     0.40
Rivers, SD                                       0.36
Campbell, Was                               0.35
Kitna, Det                                       0.34
Rosenfels, Hou                               0.32
Edwards, Buf                                  0.32
Pennington, NYJ                              0.31
Losman, Buf                                   0.31
Jackson, Min                                   0.31
Culpepper, Oak                               0.30
Huard, KC                                        0.30
Lemon, Mia                                      0.30
Griese, Chi                                      0.28
Boller, Bal                                       0.28
Manning, NYG                                 0.26
Bulger, StL                                      0.26
McNair, Bal                                      0.25
Testaverde, Car                              0.25
Croyle, KC                                       0.25
Grossman, Chi                                0.25
Young, Ten                                     0.24
Clements, NYJ                                0.23
Smith, SF                                        0.18
Frerotte, StL                                  0.12
McCown, Oak                                 0.03
Dilfer, SF                                         0.01