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 thing 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.
With that in mind, and also bearing in mind that it's only been one game, here's how the quarterbacks fared over the weekend, who had at least ten attempts:
Romo, Dal, 1.10
Brady, NE, 1.06
P Manning, Ind, 0.97
Cutler, Den, 0.87
Hasselbeck, Sea, 0.78
Delhomme, Car, 0.74
Roethlisberger, Pit, 0.66
Garcia, TB 0.63
Gerrard, Jac 0.63
Schaub, Hou, 0.61
E Manning, NYG, 0.59
Palmer, Cin, 0.55
Pennington, NYJ, 0.55
Green, Mia, 0.52
Jackson, Min, 0.45
Kitna, Det, 0.43
Campbell, Was, 0.39
Bulger, StL, 0.38
McNabb, Phi, 0.35
Anderson, Cle, 0.28
Rivers, SD 0.23
Smith, SF, 0.21
Favre, GB, 0.17
McCown, Oak, 0.17
Harrington, Atl, 0.13
Grossman, Chi, 0.12
McNair, Bal, 0.11
Brees, NO, 0.09
Huard, KC, 0.08
Clements, NYJ, 0.00
Leinart, Ari -0.07
Losman, Buf, -0.08
Young, Ten, -0.09
Frye, Cle, -0.38
Boller, Bal, -0.68
For comparison purposes, the average league over the last ten years using this metric runs a little under 0.40. The best single season of the last 15 years or so was Peyton Manning in 2004, when he created 0.73 points per pass.
As time allows, I intend to update the results each week.