A project for the group- Update and improve the QB rating

[MightyGiants]

I think this might prove to be a good excercise for the group.  The PR has been around for many years.  During that time the game has changed significantly.  I wonder if we put our heads together we good produce a better modern one.  Anyone game?

For reference, here is the current formula

The NFL rates its passers for statistical purposes against a fixed performance standard based on statistical achievements of all qualified pro passers since 1960. The current system replaced one that rated passers in relation to their position in a total group based on various criteria.

The current system, which was adopted in 1973, removes inequities that existed in the former method and, at the same time, provides a means of comparing passing performances from one season to the next.

It is important to remember that the system is used to rate passers, not quarterbacks. Statistics do not reflect leadership, play-calling, and other intangible factors that go into making a successful professional quarterback.

Four categories are used as a basis for compiling a rating:
1. Percentage of completions per attempt
2. Average yards gained per attempt
3. Percentage of touchdown passes per attempt
4. Percentage of interceptions per attempt

The average standard, is 1.000. The bottom is .000. To earn a 2.000 rating, a passer must perform at exceptional levels, i.e., 70 percent in completions, 10 percent in touchdowns, 1.5 percent in interceptions, and 11 yards average gain per pass attempt. The maximum a passer can receive in any category is 2.375.

For example, to gain a 2.375 in completion percentage, a passer would have to complete 77.5 percent of his passes. The NFL record is 70.55 by Ken Anderson (Cincinnati, 1982).

To earn a 2.375 in percentage of touchdowns, a passer would have to achieve a percentage of 11.9. The record is 13.9 by Sid Luckman (Chicago, 1943).

To gain 2.375 in percentage of interceptions, a passer would have to go the entire season without an interception. The 2.375 figure in average yards is 12.50, compared with the NFL record of 11.17 by Tommy O'Connell (Cleveland, 1957).

In order to make the rating more understandable, the point rating is then converted into a scale of 100. In rare cases, where statistical performance has been superior, it is possible for a passer to surpass a 100 rating.

For example, take Steve Young's record-setting season in 1994 when he completed 324 of 461 passes for 3,969 yards, 35 touchdowns, and 10 interceptions.

The four calculations would be:

Percentage of Completions — 324 of 461 is 70.28 percent. Subtract 30 from the completion percentage (40.28) and multiply the result by 0.05. The result is a point rating of 2.014.
Note: If the result is less than zero (Comp. Pct. less than 30.0), award zero points. If the results are greater than 2.375 (Comp. Pct. greater than 77.5), award 2.375.

Average Yards Gained Per Attempt — 3,969 yards divided by 461 attempts is 8.61. Subtract three yards from yards-per-attempt (5.61) and multiply the result by 0.25. The result is 1.403.
Note: If the result is less than zero (yards per attempt less than 3.0), award zero points. If the result is greater than 2.375 (yards per attempt greater than 12.5), award 2.375 points.

Percentage of Touchdown Passes — 35 touchdowns in 461 attempts is 7.59 percent. Multiply the touchdown percentage by 0.2. The result is 1.518.
Note: If the result is greater than 2.375 (touchdown percentage greater than 11.875), award 2.375.

Percentage of Interceptions — 10 interceptions in 461 attempts is 2.17 percent. Multiply the interception percentage by 0.25 (0.542) and subtract the number from 2.375. The result is 1.833.
Note: If the result is less than zero (interception percentage greater than 9.5), award zero points.

The sum of the four steps is (2.014 + 1.403 + 1.518 + 1.833) 6.768. The sum is then divided by six (1.128) and multiplied by 100. In this case, the result is 112.8. This same formula can be used to determine a passer rating for any player who attempts at least one pass.

Here is another good reference

• Tweet

[MightyGiants]

To sort of facilitate things, what things do you feel the current rating system fail to measure?

Of these, which should (or could) be added?

How would you measure that attibute or performance?

How important is it, compared to the existing numbers?

Looking over the numbers the current system weighs all numbers equally.  Is that good?

[vette]

We would need accurate stats to compare quarterbacks but, try to work with this formula:

1) # of completions minus # of incompletion's divided by attempts

2) Add the number of passing conversions multiplied by their weight together. Divided  by the number of completions,                                                                                               total first downs x 1, + passing third downs x 2, + passing fourth downs x 3.

3) touchdown passes, minus interceptions and turnovers by QB

Obviously I don't feel that yards per attempt should factor into the efficiency of a QB's play.
I need to evaluate this better and tweak it here and there, but this is the rough draft.  I need to work on an equation.

 

[MightyGiants]

Ed,

Yards per completion was the way to level the field between QBs playing in a completion percentage friendly West Coast offense and a lower percentage vertical attack.  It also gave more credit to the QB that hit his down field receiver, rather than just dump it off to his RB.    How would you system compensate for that?   

[vette]

Yards per completion are the result of the play called. Usually there are more pass attempts in traffic in a WCO, thus the difficulty factor there. How many WCO's really exist in today's game?

Now compare Tom Brady's stats with Eli Manning. Brady's YPC is 8.31. Manning's is 6.31. Brady passed 49 times more, 578/529. The difference in points toward the rating is 8.33 points. Would you consider the Pats a WCO? Of course not. Is that 8.33 points meaningful in comparing the 2 quarterbacks? I don't believe so. The system rewards in a minimal way, large total yards gained. If one QB threw 10 passes for 30 yards each and 10 passes for 5 yards each, his YPC would be 17.5. Another QB throws 20 passes for 20 yards and his   average is 20.0. Does it tell us anything if we factor in pass rush, how many times they were passing under blitz. Quality of receivers to catch the ball?

In my system, they are being rated on:
1) Net completion %
2) Productivity in difficult situations.
3) Net touchdown passes. How productive was Eli after you take away INT's and Fumbles?

[vette]

One other thing Rich. The current system evaluates on 4 criteria. My system evaluates based on consideration of 8 criteria.