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 90 pass attempts.

After crunching the numbers, sorting them, and giving them one final look-over, I wondered what sort of mistake I made.  Peyton Manning was ranked second last week, and I know he had that atrocious game, but I kept looking further and further down the list and couldn't find him.  After locating him down at the tenth spot, I went back and double-checked my numbers.  There's no math error, folks; Peyton took a serious tumble.  Six picks and a poor yards per pass value can wreck even a legend's passing numbers.

Our main man Romo benefitted by moving up into fourth place; while the other Manning saw his value dip after playing against a clearly improving Dallas defense.

We are facing another QB this week whose value lies in the middle of the pack.  With the Redkins injuries starting to pile up in their secondary, Tony could be in for another big week.

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                                        0.73
Garrard, Jax                                    0.61
Garcia, TB                                        0.60
Romo, Dal                                       0.55
Favre, GB                                        0.55
Anderson, Cle                                 0.51
Hasselbeck, Sea                             0.50
McNabb, Phi                                    0.50
Palmer, Cin                                     0.49
Manning, Ind                                  0.49
Roethlisberger, Pit                          0.48
Harrington, Atl                                0.45
Cutler, Den                                     0.42
Schaub, Hou                                   0.41
Brees, NO                                       0.41
Losman, Buf                                   0.40
Warner, Ari                                     0.40
Kitna, Det                                       0.39
Boller, Bal                                       0.38
Pennington, NYJ                             0.36
Campbell, Was                               0.35
Leinart, Ari                                      0.33
Bulger, StL                                      0.32
Manning, NYG                                 0.31
Green, Mia                                      0.31
Lemon, Mia                                     0.31
Edwards, Buf                                  0.30
Huard, KC                                       0.30
Rivers, SD                                       0.27
Griese, Chi                                      0.27
McNair, Bal                                      0.25
Clements, NYJ                                 0.25
Jackson, Min                                   0.25
Carr, Car                                        0.21
Culpepper, Oak                              0.21
Smith, SF                                        0.18
Young, Ten                                     0.14
Grossman, Chi                                0.08
McCown, Oak                                -0.08