As we all know (or should know, anyway), the NFL passer rating is strictly a measure of passing efficiency; it does not take into consideration a quarterback's rushing statistics. The four statistical categories that comprise the NFL passer rating are completion percentage, yards per attempt, touchdowns per attempt, and interceptions per attempt. The formula was designed in the 1970s to rate an average performance for a quarterback of that era as 66.7 and an excellent performance as 100.0.
The nice thing about this formula is it is an "absolute" measure that allows us to compare quarterback passing performances across eras. The disadvantage is that it the scale is artificially flattened at both ends, such that it's impossible to get higher than a 158.3 or lower than a 0.0, and it doesn't take into consideration a quarterback's rushing attempts or his fumbles. It's a
passer rating, not a
quarterback rating. The other problem is that it fails to account for season-to-season variation in leaguewide performance, so it makes it more difficult to get a feel for how quarterbacks are performing
relative to each other on a year-to-date basis. For example, a passer rating of 110.0 looks great on paper, and if the league average is 85.0, it really is impressive; but if the league average is 105.0 this year, a 110.0 rating doesn't stand out nearly so much.
For these reasons, I thought I would try my hand at designing a more open-ended, relative quarterback rating system that would take passing, rushing, and turnovers into consideration while minimizing the effects of changes in the landscape of the league from season to season.
Below is a table comparing three different preliminary versions of the rating system, so you can get a feel for how they vary in the results they return. I want to get your feedback as to which one you think returns the most useful results and/or your suggestions for ways to improve the formulas further.
Rating a weights the following statistical categories equally: yards per passing attempt, yards per rushing attempt, touchdown:turnover ratio, and completion percentage. The weighting of the rushing category hurts quarterbacks who are statues in the pocket, while the inclusion of completion percentage favors dink-and-dunk quarterbacks.
Rating b weights the following statistical categories equally: yards per play, touchdown:turnover ratio, and completion percentage. Lumping rushing and passing together in a single category like this inherently weights rushing and passing yardage by the number of attempts; this favors immobile quarterbacks at the expense of rushing quarterbacks, since not even the most run-happy quarterback rushes nearly as often as he passes.
Rating c weights the following statistical categories equally: yards per play and touchdown:turnover ratio. The advantage of this method is its simplicity; it measures a quarterback's efficiency at moving the ball down the field and avoiding turnovers. The disadvantage is that it could arguably be considered more of an offensive rating than a quarterback rating, although it really isn't, since it ignores rushes by anyone not the quarterback.
It's worth emphasizing that this is a
relative quarterback rating. It's not based on a body of statistics from prior seasons -- it rates quarterbacks against each other with respect to their relative performances
this year. It gives you the ability to more consistently and objectively define terms like "elite" and "mediocre" from season to season. If you want to define an elite quarterback as one whose performance is in the 95th percentile or above (my personal definition), then it's obvious that there is only one quarterback in the league this year who is playing at an elite level across statistical categories.
Player Rating a Rating b Rating c
Drew Brees 81.05 99.43 104.49
Philip Rivers 51.86 65.77 69.45
Patrick Mahomes 62.02 64.85 68.53
Jared Goff 59.16 65.98 68.06
Ryan Fitzpatrick 61.65 63.52 66.38
Matt Ryan 61.16 65.37 62.97
Mitchell Trubisky 61.32 54.96 56.01
Aaron Rodgers 52.54 50.39 55.95
Russell Wilson 58.92 55.25 55.67
Deshaun Watson 56.45 53.73 55.09
Ben Roethlisberger 51.60 53.65 53.12
Jimmy Garoppolo 47.61 46.52 52.46
Carson Wentz 56.39 58.17 52.33
Jameis Winston 54.08 50.37 50.05
Derek Carr 50.03 55.31 47.27
Tom Brady 43.06 48.72 47.12
Cam Newton 54.44 51.94 46.84
Eli Manning 44.76 50.94 46.74
Andy Dalton 46.58 46.07 46.38
Kirk Cousins 50.89 54.15 45.84
Case Keenum 45.94 46.04 45.57
Ryan Tannehill 50.96 48.28 45.37
Marcus Mariota 53.22 48.98 44.72
Matthew Stafford 46.90 48.63 44.51
Blake Bortles 49.71 42.94 44.47
C.J. Beathard 43.25 41.42 43.58
Baker Mayfield 46.90 42.44 42.94
Dak Prescott 49.39 44.72 42.81
Alex Smith 45.39 44.02 41.76
Andrew Luck 44.55 46.15 41.56
Brock Osweiler 41.37 43.14 41.38
Joe Flacco 37.65 38.57 38.08
Sam Darnold 31.91 30.52 35.57
Tyrod Taylor 37.20 23.52 33.72
Josh Rosen 36.32 29.93 33.45
Josh Allen 33.77 25.63 29.77
Legend:
Standard deviations
Scale from mean Percentile Evaluation
100 +3.0 99.9 Stellar
50 0.0 50.0 Average
0 -3.0 0.1 Shitty
If anyone wants an in-depth description of the mathematics behind the three rating systems, I'll be happy to provide it.
What do you people think? What did I get right? What did I get wrong? What did I miss that I should have included, or what did I include that I should have left out?