I cross posted this from my other blog – Adventures in Missing the Point. That blog is mostly just for random thoughts and rants, but I wanted this post to get a wider distribution.
In a recent conversations with another football enthusiast, the topic of the passer rating became a subject of great disgust. Most of us, even the most ardent football fans among us, could not tell you how this extremely confusing, mysterious and well-muddled statistic is calculated or WHY a perfect passer rating is 158.3 and not 0 (the perfect ERA for a pitcher in baseball) or 1.000 (for hitters in baseball). So I researched it a little. Here is what I found:
Calculations
The passer rating is calculated by the following formula (I’m not making this up):
[((completion/attemptions*100)-30)/20] + [(yards/attempts – 3)/4] + [# of touchdowns/attempted X 20] + [2.375 – ((interceptions/attempts)*25)]
then, the answer is divided by 6 and then multiplied by 100. If an individual value – inside the square brackets – is less than 0, it is 0 for calculations. If it is greater than 2.375, it is still 2.375.
This may sound bogus and ridiculous, but I assure you this is the way they calculate it.
Tom Brady, Week 1
I will use Brady’s week 1 game against the Jets as an example.
- Completions = 22
- Attempts = 28
- Yards = 297
- TD = 3
- Interceptions = 0
So his passer rating was 146.6 because…
[((22/28*100)-30)/20] + [(297/28 – 3)/4] + [3/28 X 20] + [2.375 – ((0/28)*25)] / 6 * 100
Ben Roethlisberger, Week 15
In order to illustrate how absurd this is, I will now pull out the numbers for Ben Roethlisberger’s “perfect game” a couple of weeks ago on Thursday night. As we have been reminded…repeatedly…Roethlisberger got a perfect passer rating. Here are his stats:
- Completions = 16
- Attempts = 20
- Yards = 261
- TD = 3
- Interceptions = 0
[((16/20*100)-30)/20] + [(261/20 – 3)/4] + [3/20 X 20] + [2.375 – ((0/20)*25)] / 6 * 100
Although statistically, the two were pretty much equal (Brady had 36 more yards but Roethlisberger’s completion percentage was 1.4% higher), Roethlisberger gets a higher score.
Tom Brady’s Perfect Game
Now consider Brady’s “perfect” game from Week 7.
- Completions = 21
- Attempts = 25
- Yards = 354
- TD = 6
- Interceptions = 0
Ahh, Grading on the Curve
Although Brady’s game was FAR superior to Roethlisberger’s in EVERY WAY, they both had “perfect” games. WHY? Because the system is a great example of a sliding scale.
When Don Smith devised the system in 1973, the idea was that the worse you did, your rating declined faster. Of course, Smith assumed 66.667 as the average score and created a system around that score. The problem is that the average rating in 2003 was 78.9, and in 2004 (thanks to Peyton Manning, 
Tom Brady, and a few others) it was 82.8.
In short, the passer rating is entirely meaningless and has no value whatsoever. If two quarterbacks can have games just a few weeks apart where one (Tom Brady) out throws the other (Roethlisberger) by nearly 100 yards and doubles the number of touchdowns, and the two have identical passer ratings…then the ratings system is flawed.
okay…obviously the person who wrote these comments is a Patriots fan. As I am a Steelers fan I will comment by saying only this. As Tom Brady may be a more seasoned quarterback, lets not forget that in both of their separate perfect games, the reason Ben’s is more because he threw accurately without having to complete 22 passes out of 28 attempts. He completed 16 passes out of 20, 2 less missfires than Brady. If this makes sense to you, than great I have made my point, but if not, than you will continue to praise Brady and the Patriots and refer to Ben as somewhat inferior…your choice. GO STEELERS!
That is true that he “misfired” 2 fewer times, however, Brady threw for nearly 100 yards more AND twice as many touchdowns.
My point was not that Brady is a better quarterback but that he had a better game, but the passer rating does not make allowances for that.
Actually, I’m a Buccaneers fan.
I think the author should have devoted a larger part of his article to highlighting how passer rating really have little meaningful correlation to a quarterbacks ability to win you games. It merely shows you how flash the QB’s passing stats are. Case in point if you look at career passer rating of QB’s with at least 1500 attempts, Matt Schaub is number 13 all time, and he’s terrible, a QB disaster who is lucky to cling to 3rd on the depth chart at this point in his career. He as a higher career passer rating than other great passers like Dan Marino and Andrew Luck. Do those stat mean something? Yes, a little but to simply assert that higher passer rating means better QB is a little foolish…
“In short, the passer rating is entirely meaningless and has no value whatsoever.”
I think that line pretty much sums up the lack of correlation between the rating and a QB’s ability to win games.