Off the top of your head, could you say exactly how the NFL passer rating is calculated?
Probably not. I'm sure you could look it up quickly, but it doesn't matter that much anyway. Because as long as we understand what goes into the rating, the exact formula isn't that important. The passer rating aggregates yards per attempt and completion percentage as well as TD and INT percentages into one more-or-less easy to understand number.
For all its faults, the passer rating does go beyond simple volume stats like yards, number of TDs or number of interceptions. This is a good thing. Yet to this day, it remains perhaps the only advanced stat used to evaluate a passer. That is a bad thing.
So today I'm going to look at some stats out there that help paint a more complete picture of the passer performance than the passer rating or the more traditional volume stats are able to, and I'll use the four NFC East quarterbacks as an example.
Note that in the intro above I used the word 'passer' six times and 'quarterback' only once. This is an important distinction. The NFL passer rating was designed to evaluate the passing game only. It does not account for a quarterback's running game, his ability to read defenses, his competence as a signal caller, his decision making and many other aspects of quarterback play. And the same is true for most of the stats we'll be using below: they are focused on the passing game, not the entirety of quarterback play.
Let's start with where the four NFC East QBs currently stand as measured by the traditional Passer Rating:
|2011 Passer Rating, NFC East QBs|
This is about what you would have expected, right? At 97.5, Romo is just two points above his career average, so he's having a normal year, albeit at a very high level. Eli Manning is on track to have a career year and is playing about 15 points above his career average. Both Vick and Grossman are playing within less than one point of their career average. This is who they are.
Vick and Grossman are below Romo and Manning in terms of completion percentage and yards per attempt, but not enough to explain the big difference in their passer ratings. The key difference between the two sets of QBs is in the number of TDs and INTs thrown. Romo and Manning have very similar TD/INT numbers (Romo: 22 TD, 9 INT; Manning: 23 TD, 11 INT) while Vick (11 TD, 11 INT) and Grossman (10 TD, 15 INT) have much less favorable numbers. Plugging in Romo's 22 TDs and 9 INTs (adjusted for differing number of pass attempts) into Vick's and Grossman's numbers would significantly improve Vick's (91.3) and Grossman's (86.3) passer ratings.
Before we proceed, please make a mental ranking of which QB you think is the most accurate with his throws. Got it? Okay.
The traditional way of recording accuracy, the NFL's completion percentage, is actually not a very accurate way to measure a QB's passing accuracy. For example, did you know that a spiked ball officially counts as an incomplete pass? Same thing with a ball that is thrown away into the stands, although that at least makes some sort sense. But counting it as an incomplete pass gives it a negative mark even though it may have been the right decision in order to avoid a sack.
And then there are the dropped balls by wide receivers. It certainly doesn't help Michael Vick's accuracy that he has to throw balls to DeSean Drop'em Jackson.
Pro Football Focus take all of this into account in their Accuracy Percentage. The formula: (Completions + Drops) / (Attempts - Throw Aways - Spikes). Here's how the four QBs rank in accuracy percentage:
|2011 Accuracy Percentage, NFC East QBs|
Now go back to your mental ranking. Is this the picture you expected? It certainly wasn't what I expected. In terms of accuracy, Romo, Manning and Vick are virtually identical. Only Grossman drops off somewhat, and is much better than I expected.
Deep Passing Accuracy
One of the memes about Tony Romo that pop up again and that no amount of data seems able to weed out is that Romo is supposedly unable to throw deep balls. Well, here's yet another set of numbers showing that particular storyline to be complete bunk. Deep passing accuracy measures the accuracy on passes that travel 20 yards downfield through the air.
|2011 Deep Passing Accuracy, NFC East QBs|
Romo and Vick are ranked 4th and 3rd among all NFL QBs. As is to be expected, Aaron Rodgers is running laps around everybody with a 64.6 percentage. But Vick's number does come as a bit of a surprise. Perhaps I have bought too much into the popular storyline that Vick is an "average passer and a great runner", when in fact he is a very accurate passer and a great runner.
Passing under pressure
We all have our pet theories about NFL QBS. About how one guy is particularly accurate, how another guy throws a great deeep pass, or how yet another is particularly good under pressure.
Well, we already saw that for the first two points, we have some surprising results even among the small sample of the four NFC East QBs. The latter point, passing under pressure, is yet another one where the data defies some of the established storylines.
|2011 Situational Passer Rating, NFC East QBs|
Tony Romo is the best NFC East QB when under pressure, with Manning taking up the second spot. Michael Vick, who less than three months ago told Yahoo's Michael Silver, "You can't design a defense to stop me", is particularly susceptible to pressure. Vick threw nine of his eleven interceptions while under pressure. Pressure Vick and he'll fold; give him a clean pocket and you'll be down 21-0 five minutes into the second quarter.
Texas lore holds that the legendary UT football coach Darrell Royal once said, "Three things can happen when you pass the football, and two of them are bad."
Obviously, there is no stat that measures a QBs decision making. However, in today's pass-heavy NFL, the passer who can pass effectively while minimizing his mistakes is going to be the more successful player. In the NFC East this year, despite all the headlines to the contrary, that is Tony Romo. He has the fewest interceptions per pass attempt, remains the most effective under pressure and is right up there in terms of accuracy and deep ball passing skills.
For all intents and purposes, Manning and Romo are playing at almost identical levels this year. The difference between them and Vick/Grossman is that they are making fewer mistakes as passers. And the difference between Romo and Manning is that for Romo, this is normal. For Manning, this year is the exception.
Having said all that - this may come as a shocking revelation to many football fans - it shouldn't come as a surprise to see that Tony Romo leads the team with the best record in the NFC East.