Introducing the PiRate NFL Pass Rating Formula

 

The National Football League has been using the same pass rating formula for multiple decades.  It uses a combination of completion percentage, yards per attempt, touchdowns, and interceptions.  If you want to calculate it on your own, here it is:

 

I.     (Completion Percentage-30.0) * 0.05 +

II.    (Yards per attempt-3.0) * 0.25 +

III.   (20 * touchdowns per pass attempt) +

IV.   2.375 – (25 * interceptions per pass attempt)

 

If any of these four components are greater than 2.375, then cap the value at 2.375

 

Add these four stats together and multiple them by 16.667 to get the passer rating.  Here is an example:

 

In 1963, Y. A. Tittle had these stats for the New York Giants

Completions 221  Attempts 367  Yards 3145  Touchdowns 36  Interceptions 14

 

I.     (60.20 – 30.0) * 0.05 = 1.51  +

II.    (8.57-3.0) * 0.25 = 1.39        +

III.   (20 * .098) = 1.96                +

IV.   2.375 – (25 * .038) = 1.43    +

 

 Subtotal = 6.29     6.29 * 16.667 =

                     104.8

 

Once you know this formula, you can easily plug it into a spreadsheet and figure the ratings.  However, these ratings are a poor way to select the most efficient passer.

 

Let’s take a look at two opposing passers, Smith and Jones.

 

Smith completes 15 of 24 passes for 3 touchdowns with no interceptions.

 

Jones completes 10 of 24 passes for 0 touchdowns and 1 interception.

 

Smith is obviously much better, correct?  No, not correct.  It depends on several other things.  What if Jones has a lousy offensive line or receivers that drop every other pass thrown to them?  What if Smith has all day to pass with Jerry Rice-type receivers?  All these stats show us are just that—their stats.

 

Smith could have completed six passes to backs behind the line of scrimmage with the backs following blocking for long gains.  Jones could have threaded the needle with 30 yard passes to the deep sidelines only to have had them dropped by inept receivers.

 

In essence no pass-rating formula is worth a grain of salt.  Let’s look at two separate plays.  Passer A completes 13-yard pass for a touchdown.  It is a dump pass into the flat to the tailback with the tailback avoiding three defenders as he streaks into the end zone.  This one pass gets the NFL Maximum rating of 158.3.

 

Now, let’s look at Passer B.  His team is backed up at their own 1 yard line. He drops back and fires a bomb 55 yards through the air that comes down perfectly in the hands of his flanker.  The flanker takes off down the sideline and is knocked out just one yard from scoring.  This 98-yard pass gives Passer B a rating of 118.8!  Peyton Manning actually had a better total season rating than this a couple years ago, and even though he ranks among the best ever, he was not worth a 98-yard completion every time he threw the ball!

 

Can this be?  You betcha!  The rating is flawed.  Obviously the brilliantly thrown pass that travelled 55 yards past the line of scrimmage that comes down perfectly in the hands of the intended receiver should be worth a lot more than the dump pass that I could complete given two seconds protection.

 

Here is where the PiRate Pass Rating Formula tries to correct the incorrect values of the NFL Pass Rating Formula.

 

Our formula looks at just two statistics.  The first is interception percentage.  An intercepted pass is worth anywhere from 3 to 7 points for the other team on average.  We realize that all interceptions are not the same.  A poorly thrown pass into the flat at the offense’s 20-yard line hurts much more than a 3rd and 25 pass thrown 40 yards downfield and intercepted by the defense. 

 

The second stat is called “Air Yards Per Attempt,” or AYPA.  It is simply the passing yardage minus the yards after catch.  If Passer A completed a 51-yard pass for a touchdown, but the play consisted of a pass completed to a tailback one yard past the line of scrimmage with the back running for 50 yards, the passer gets credit for an AYPA of 1 yard (51 yard pass – 50 yards after the catch).

 

Here is the PiRate Pass Rating Formula:

[AYPA * 7 – (11 * Interception %) + 105] * 0.8

 Interception percentage is figured as: (Interceptions/Attempts) *100

 Anything over 100 is an excellent rating.  Over 90 means the QB is above average.  80 would be considered average; below 80 means this QB should be looking over his shoulder for a replacement to take his job.

 In our passer rating, we don’t include passing percentage or touchdown passes.  Yards gained are what matters.  Three consecutive completed passes that gain a total of nine yards means 4th & 1.  Two incomplete passes followed by an 11 yard completion means 1st & 10.  Which outcome is better?

 Touchdowns skew the ratings.  If one coach sends in passing plays at the opponents’ one yard line, while another sends his 240-pound power back to plunge over the goal, the quarterbacks will get too much credit in once instance and no credit in the other. 

 Let’s take a look at the PiRate Rating in action.  First, you must be wondering where can you find AYPA?  There is an excellent website that carries this stat, so you don’t have to try to figure out the YAC for each QB.  Go to: www.advancednflstats.com. 

 Here is a look at both ratings side-by-side:

Player	PiRate QB Rating		Player	Official NFL Rating
Aaron Rodgers	108.9	|||	Drew Brees	109.6
Drew Brees	107.5	|||	Brett Favre	107.2
Brett Favre	106.7	|||	Phil Rivers	104.4
Tony Romo	105.6	|||	Aaron Rodgers	103.2
Phil Rivers	104.8	|||	Ben Roethlisberger	100.5
Ben Roethlisberger	97.9	|||	Peyton Manning	99.9
Matt Schaub	97.8	|||	Matt Schaub	98.6
Peyton Manning	97.2	|||	Tony Romo	97.6
Donovan McNabb	96.3	|||	Tom Brady	96.2
David Garrard	96.1	|||	Kurt Warner	93.2
Kyle Orton	94.7	|||	Eli Manning	93.1
Brad Gradkowski	94.4	|||	Donovan McNabb	92.9
Tom Brady	93.8	|||	Joe Flacco	88.9
Kurt Warner	93.4	|||	Kyle Orton	86.8
Eli Manning	92.8	|||	Jason Campbell	86.4
Vince Young	92.1	|||	Carson Palmer	83.6
Joe Flacco	87.7	|||	David Garrard	83.5
Marc Bulger	86.7	|||	Vince Young	82.8
Jason Campbell	85.4	|||	Alex Smith	81.5
Matt Ryan	83.0	|||	Matt Ryan	80.9
Carson Palmer	81.7	|||	Brad Gradkowski	80.6
Chad Henne	80.8	|||	Jay Cutler	76.8
Alex Smith	79.7	|||	Chad Henne	75.2
Brady Quinn	78.4	|||	Matt Hasselbeck	75.1
Matt Hasselbeck	75.7	|||	Trent Edwards	73.8
Matt Cassel	75.7	|||	Marc Bulger	70.7
Kerry Collins	72.1	|||	Matt Cassel	69.9
Trent Edwards	69.9	|||	Ryan Fitzpatrick	69.7
Kyle Boller	69.1	|||	Brady Quinn	67.2
Jay Cutler	67.3	|||	Kerry Collins	65.5
Ryan Fitzpatrick	64.3	|||	Mark Sanchez	63.0
Mark Sanchez	60.9	|||	Kyle Boller	61.2
JaMarcus Russell	56.4	|||	Matt Stafford	61.0
Matt Stafford	54.1	|||	Josh Freeman	59.8
Jake Delhomme	51.5	|||	Jake Delhomme	59.4
Josh Freeman	46.4	|||	JaMarcus Russell	50.0
Derek Anderson	46.3	|||	Derek Anderson	42.1

 

Coming tomorrow: We reveal the initial NFL PiRate, Mean, and Bias ratings for the 2010 season and give our predictions for each division.