Football 101: QB Rating System

[Hostile]

I also said he would have good games but magically you forgot that. I think we have 15 more games to go.

I didn't forget.

 

[theebs]

http://img40.*************/img40/9974/romoypa.jpg
http://img179.*************/img179/6268/owensbigplaycomparison.jpg

 

[sonnyboy]

A. The calculation for completion %.

1. # completions is divided by # of attempts.
2. This number is then multiplied by 100.
3. Take that number and subtract 30.
4. Divide that number by 20.

This is the number you will plug into the formula later for the Letter A.


B. The calculation for yards per attempt.

1. # of yards is divided by # of attempts.
2. Take that number and subtract 3.
3. The new number is multiplied by .25.

This is the number you will plug into the formula for the Letter B.


C. The calculation for Touchdowns per attempt.

1. # of TD passes is divided by the # of attempts.
2. This number is multiplied by 20.

This is the number you will plug into the formula for Letter C.


D. The calculation for Interceptions per attempt.

1. # of Interceptions is divided by # of attempts.
2. This number is multiplied by 25.
3. The new number is subtracted from 2.375. (Note: do not subtract 2.375 from the number in line 2. Subtract the number in line 2 from 2.375.)

This is the number you will plug into the formula for Letter D.


Now you will use these 4 calculations and make one final number which is the QB rating.

1. Add A + B + C + D.
2. Divide this number by 6.
3. Multiply the new number by 100.

This gives you the QB rating.

I really wish someone credible would come up with a better formula. Some HOF QB. Anybody credible enough to be taken seriously and have his new improved formula adopted by the powers that be.

This formula has few critical flaws as I see it.

1) Completion%. Why is it even included? You already have the most meaningful number, YPA included. It's like you're double counting or rewarding QB's who throw for a higher percentage completion regardless of YPA.
Completion percentage,or A, should just be removed. Then you could double weight YPA, or B.

2) The other problem is with TD Pass%. This part of the equation should be completely reworked. It should included all points scored by the QB's offense. FG's included. Perhaps a double weighting for actual TD passes. But their needs to be some sort of credit factored in for all points the QB lead his team to.

 

[Hostile]

you can save that kinda talk for WG, she is into it.

It didn't work with her either.

 

[adamknite]

I really wish someone credible would come up with a better formula. Some HOF QB. Anybody credible enough to be taken seriously and have his new improved formula adopted by the powers that be.

This formula has few critical flaws as I see it.

1) Completion%. Why is it even included? You already have the most meaningful number, YPA included. It's like you're double counting or rewarding QB's who throw for a higher percentage completion regardless of YPA.
Completion percentage,or A, should just be removed. Then you could double weight YPA, or B.

2) The other problem is with TD Pass%. This part of the equation should be completely reworked. It should included all points scored by the QB's offense. FG's included. Perhaps a double weighting for actual TD passes. But their needs to be some sort of credit factored in for all points the QB lead his team to.

I don't know if you were being sarcastic or not, but Troy Aikman has come up with one I believe (or maybe his is for the whole offense... I can't remember). Of course if you were being sarcastic... you already knew that.

 

[Hostile]

I don't know if you were being sarcastic or not, but Troy Aikman has come up with one I believe. Of course if you were being sarcastic... you already knew that.

I think Aikman's power ratings were far superior to any I have ever seen.

 

[adamknite]

I think Aikman's power ratings were far superior to any I have ever seen.

Yeah, I agree.

http://www.nytimes.com/2005/12/13/sports/football/13sandomir.html

Just for anybody interested.

 

[kmd24]

Hos --

I've got the whole mathematical stuff down, but my question is do you know if there's any basis to why certain numbers/variables are used in the calculation? Why did they pick .25, for example, or this equation at all instead of something more simple?

It was devised in 1973 and is more or less based on the average completion percentage, TD%, INT%, and yards per attempt of that era. The idea was to fit an equation based on aggregate QB data so that the average turned out to be 66.6, which would correspond to a term of 1 for each of the A, B, C, D items Hos listed in the OP. That would be a comp% of 50%, ypa of 7.0, TD% of 5%, and a INT% of 5.5%. That was the average QB in 1973, but would be a horrible QB today.

It's basically a statistical model that tries to rate each category equally and assign a statistic to each category based on where the number falls within the aggregate of all QB's.

It's outdated and imperfect, but it's just a statistic. It doesn't seem that useful for comparing two quarterbacks, and it's pretty useless for comparing QB's between eras. But it's a number, and in sports that makes for great debate.

 

[Eldorado]

I *JUST* finished my calculus homework, and came on here to look at football.

I just looked at math.

And wrote it down.

I hate you.

 

[Hostile]

It was devised in 1973 and is more or less based on the average completion percentage, TD%, INT%, and yards per attempt of that era. The idea was to fit an equation based on aggregate QB data so that the average turned out to be 66.6, which would correspond to a term of 1 for each of the A, B, C, D items Hos listed in the OP. That would be a comp% of 50%, ypa of 7.0, TD% of 5%, and a INT% of 5.5%. That was the average QB in 1973, but would be a horrible QB today.

It's basically a statistical model that tries to rate each category equally and assign a statistic to each category based on where the number falls within the aggregate of all QB's.

It's outdated and imperfect, but it's just a statistic. It doesn't seem that useful for comparing two quarterbacks, and it's pretty useless for comparing QB's between eras. But it's a number, and in sports that makes for great debate.

Oh wow, that was outstanding. Thank you.

 

[sonnyboy]

I don't know if you were being sarcastic or not, but Troy Aikman has come up with one I believe (or maybe his is for the whole offense... I can't remember). Of course if you were being sarcastic... you already knew that.

No I wasn't. Actually forgot about that. But I do think it was for a whole unit, Offense/Defense.

He'd probably agree with some of what I had to say. Especially the idea of rewarding a QB for all offensive points scored considering how many 1 yard TDs Emmitt scored.

 

[Biggems]

Ok Hos....next on the agenda.....college football QB rating....you have 24 hours......

 

[theogt]

..

DUDE!

 

[Jimz31]

NFL.com has Tony's rating at 140.6, as does http://www.primecomputing.com/ when you manually enter in his stats.

That's the site I usually use as well.

 

[Phoenix]

We've all seen the QB ratings to gauge how well a guy has done. It is a complicated system of calculations. I thought I'd take a minute to explain them. Hope it doesn't hurt anyone's head.

First of all there are 4 initial calculations that you need. For the sake of this discussion I am going to call them A, B, C, & D. I am going to put in bold the stats you need in order to calculate the QB rating. Note that # of attempts is used in each Calculation.

No calculation will exceed 2.375. No calculation will be lower than zero. So if you get a number greater than 2.375 once a calculation is done, the number you plug in will actually be 2.375. If you get a number lower than 0 the number will be zero.

A. The calculation for completion %.

1. # completions is divided by # of attempts.
2. This number is then multiplied by 100.
3. Take that number and subtract 30.
4. Divide that number by 20.

This is the number you will plug into the formula later for the Letter A.


B. The calculation for yards per attempt.

1. # of yards is divided by # of attempts.
2. Take that number and subtract 3.
3. The new number is multiplied by .25.

This is the number you will plug into the formula for the Letter B.


C. The calculation for Touchdowns per attempt.

1. # of TD passes is divided by the # of attempts.
2. This number is multiplied by 20.

This is the number you will plug into the formula for Letter C.


D. The calculation for Interceptions per attempt.

1. # of Interceptions is divided by # of attempts.
2. This number is multiplied by 25.
3. The new number is subtracted from 2.375. (Note: do not subtract 2.375 from the number in line 2. Subtract the number in line 2 from 2.375.)

This is the number you will plug into the formula for Letter D.


Now you will use these 4 calculations and make one final number which is the QB rating.

1. Add A + B + C + D.
2. Divide this number by 6.
3. Multiply the new number by 100.

This gives you the QB rating.

This can be done for 1 game, a group of games, an entire season, or a career. You just need to know those stats to calculate the QB rating.


As an example, here is how Tony Romo's QB rating for Sunday is calculated.

# Completions = 16
# of attempts = 27
# of yards = 353
# of TDs = 3
# of INTs = 0

A = (16 / 27 * 100 - 30) / 20
A = 1.463

B = (353 / 27 - 3) * .25
B = 2.519

C = 3 / 27 * 20
C = 2.222

D = 2.375 - (0 / 27 * 25)
D = 2.375

(1.463 + 2.375 + 2.222 +2.375) / 6 * 100 = 140.583


Tony Romo's QB rating for Sunday was 140.583. Different stats services will round it off differently. I carried it out to 3 decimal places because the D calculation already has 3.


Now, if you will excuse me, my head hurts.

I had the QB rating formula memorized about 20 years ago

 

[burmafrd]

A.Completion % X 100/2

B. yds per attempt X 10

C. tds per attempt X 100
______________________+

then subtract

ints per attempt X 100

59.26/2=29.6
13.07X10=130.7
.11X100=11

total for Tony is 171.3

And this cuts down on what completion percentage counts for and ups yds per attempt

 

[fgoodwin]

FWIW: I know this is popularly referred to as a QB rating, but its actually a passer rating. It completely ignores a QB's rushes, rush yardage, fumbles, and sack yardage lost. So it doesn't purport to measure a QB's total performance, just his passing stats.

 

[Hostile]

FWIW: I know this is popularly referred to as a QB rating, but its actually a passer rating. It completely ignores a QB's rushes, rush yardage, fumbles, and sack yardage lost. So it doesn't purport to measure a QB's total performance, just his passing stats.

That is another reason why I like Aikman's system.

 

[theogt]

That is another reason why I like Aikman's system.

I asked this in another thread, but I guess you didn't see it. Which system are you referring to? The offensive efficiency system? I don't think Aikman has a QB rating.

 

[Hostile]

I asked this in another thread, but I guess you didn't see it. Which system are you referring to? The offensive efficiency system? I don't think Aikman has a QB rating.

Aikman had some ways to rank passing attacks in Offense that to me makes sense for QBs.

Adamknite posted a link, but I haven't gone to look yet.

All I know is Aikman's systems for Offense and Defense as a whole made better sense than current rankings. As kmd24 correctly pointed out the benchmark for those ratings are from a different generation and they don't work any longer with the advanced passing Offenses today.