QB Score QBS – Comparative QB Ratings

This article will focus on how QB Score is calculated and why it is different.  The two current popular methods of rating QB play have been Passer Rating and QBR.  Passer Rating is the 4 part, draconian formula that almost no one on the planet could quote correctly, and fewer still could perform all the calculations off-hand needed to produce the rating.  If you are interested, I included the formula at the bottom of the article.

QBR involves dividing up Expected Points based on QB play.  The cool thing about QBR, in theory, is that the QBR rating is the % chance the QB/Team has of winning the game(all other things held equal/constant).    To even begin calculating QBR you need to be able to calculate Expected Points for the offense.  If you would like to read what ESPN has to say about their own QBR formula, you can do here: ESPN QBR Explanation.

The thing Passer Rating and QBR have in common is that the rating is independent of other QB play.  Both are calculated in regard to the statistics the QB produced.  Nothing in the calculation of the Passer ratings or QBR is comparative to other QB play or stats.  Only the final rating itself is comparable, but even then it is not dependent on any other QB’s rating or play.  This is where QB Score differs.

Why QB Score?

QB Score, QBS, is derived from comparing the stats of all quarterbacks to each other and then scoring each QB in 14 categories.  To do the scoring, QBS uses Standard Deviation units.  Essentially the better a QB is compared to all his fellow QBs in that metric, the higher the score he receives for that metric.

The argument for using QBS is pretty clear:

1. It is the most intuitive of the QB rating scales with an average of virtual zero and the smallest range.
2. QBS is the easiest QB rating metric to calculate
3. QBS is the only comparative QB rating system that takes into account the QB’s performance compared to their peers.
4. Quantifying the QBS score to a descriptive adjective on the QB play is simple due the inherent ranges in its scoring system.

QB Score Metrics

Here is the process for calculating QBS.  All NFL QBs are scored in 14 statistics:

• Completion %
• Passing Yards / Game
• Intended Air Yards / Pass Attempt
• Completed Air Yards / Game
• Completed Air Yards / Pass Attempt
• Intended Air Yards/ Pass Attempt – Completed Air Yards / Pass Attempt (Inverse)
• On Target %
• Touchdown %
• Interception % (Inverse)
• 1st Down Success %
• Sack % (Inverse)
• Pressure %
• Rushing yardage / game
• Scrambling yardage / game

You’ll notice that 3 statistics have (Inverse) next to them.  This simply means when calculating, a lower value is better.  It is better to have a low INT% and Sack% so the stat/score is inverted.  At the bottom of every metric you can see the average and the size of 1 unit SD range.

Upon the release of the first version of QBS, there was suggestion that it was not rewarding more mobile quarterbacks for their play extending, and play creating talents.  Essentially that QB Score was too focused on the actual throwing of the football as opposed to scoring the position of quarterback.  A good way to think of it is that QBS would measure and rate all of Tom Brady, but only 3/4 of Lamar Jackson.

This is a fair criticism and something that needed to be tweaked if QBS was going to rate quarterbacks, and not just the ability of quarterbacks to throw the ball.   However, it had to be limited.  Even in seasons when Lamar Jackson ran for 1000 yards, he was still passing for about 3000 yards and these are the most exteme cases of rushing yds vs passing yds for quarterbacks.  A fair estimate is probably more like 500 yards rushing per 3000 yards passing is the sign of a mobile qb. As a ratio this means about 1/7 (500/3500) of the QB’s production is rushing, 6/7(3000/3500) is passing.  1/7 translates into roughly 14.3%, and for extremely mobile quarterback it could range as high as 25%(Jackson in 2019 & 2020).

Thus the ability to rush and avoid pressure should count for about 15%-20% of a quarterbacks value.  There are now 2 out of 14 metrics strictly dedicated to a quarterbacks rushing ability, or 1/7.  Considering the Pressure % metric is intended to reward quarterbacks under pressure, it is also recognizing the value of a mobile quarterback.  Thus we come to that 15%-20% area.  Ideally, QB Score would be flexible and robust enough to identify the best all around quarterback of that year whether the QB was a statuesque Tom Brady, or a Tasmanian Devil like Lamar Jackson.

New Metrics in QB Score

Pressure %

The Pressure % metric has been added to balance out how much time each quarterback has had to produce their statistics.  QBs who are facing a high % of pressure will score higher, and quarterbacks facing minimal pressure will score lowest.

The logic for including this revolves around protection scheme and line play.  If a qb faces pressure a smaller % of the time, they should, all other things held equal, produce better statistics.  They are not being rushed, or running for the lives as much.  They are sitting in a clean pocket, scanning the field, and can step into throws.

Likewise, a quarterback that is under pressure a high % of the time is most likely having to make quicker reads, scramble, and work from dirtier pockets.  Again, all other things being equal, a qb facing a high % of pressure will typically produce worse stats than a qb facing a low % of pressure.

A modern mobile quarterback is going to be helped by this metric as they will be more capable of producing positive stats after being flushed.  They simply deal with pressure better than a statuesque type quarterback.

If a team wants to Max Protect a quarterback to mimizize pressure %, that is fine, but the quarterback will be expected to produce better stats when Max Protected then when not Max Protected.  Simply put, if a qb is not performing better with extra blockers, it would be better to send the blockers out as receivers.   Their value as extra protection is zero.

Rushing Yardage / Game

This one is as straightforward as it gets.  Quarterbacks who rush the ball effectively will score high in this metric.  Kirk Cousins will not.  This stat measured the yardage gained on quarterback runs.

This metric has nothing to do with throwing the football, but has something to do with playing modern QB in the NFL.  The only small issue with this metric is the large rushing yardage range between the best of the running QBs and the Pocket Passers.  But using StDev units, the damage of a single metric with an unusual range is always limited.

Scrambling Yardage / Game

This metric rewards the quarterback who can do damage once a play breaks down.  PFR tracks scrambles and avg scramble yardage so a little multiplication give us the total scramble yardage for each quarterback.

This metric also works against the pure pocket passer, but surely a QB who can make a play out of nothing should be rewarded.  This metric can work to the advantage of QBs who never have planned runs, but become dangerous if let out of the pocket.

Intended Air Yards – The Gunslinger Metric

Every metric you see above you may have seen before or know already with the exception of two: the metrics involving Intended Air Yards.  First, Intended Air Yards is simply the measure of how far the QB threw the ball on all attempts, whether complete, or incomplete.

For example, a QB attempts a 10 yard pass but it is incomplete.  Intended Air Yards is 10, but Completed Air Yards is zero.  If the pass was complete and the receiver ran for 6 yards after the catch: Intended Air Yards is 10, Completed Air Yards is 10, YAC is 6, and Passing Yards are 16.

I am calling this the Gunslinger metric, and here is why it is included.  Ideally you would love to have a QB willing, and able, to push the ball downfield.  So let’s reward the ones who do in QBS.  All other metrics being equal, we would love it if our QB threw for 9 intended air yards every attempt as opposed to 6, because all other things being equal(including completion %), we would move down the field faster.

But all other things are not equal…Completion % decreases as intended air yards increase(its harder to complete a longer pass than a shorter one in most cases).  The ball literally takes longer to travel 9 yards as opposed to 6 yards giving defense more time to react.  Most importantly, most NFL defenses are set up to minimize long pass completions in exchange for shorter ones.  So a gunslinger QB who is always trying to go deep needs to be kept in check in QBS by making sure they are not just flinging it willy nilly downfield.

The way this is done is with the second metric, (Intended Air Yards / PA – Completed Air Yards / PA), a metric I made up.  I call this metric, The Take What The Defense Is Giving You Metric.  This is how it works…By taking IAY/PA and subtracting CAY/PA we are seeing if the QB is trying to go deep too often.  Essentially, NOT taking what the defense gives them.

Basically the more of a gunslinger the QB is(high value in column S and high points in column T), the more likely they are to have a high value in column AC(difference between intended and completed) and a low score in AD.  Remember this is an INVERSE metric, lower is better for identifying who is taking the yards available and who is pressing to throw long too often.  Thus the more aggressive a QB is, the more likely they are to be unsuccessful doing so.

The best quarterbacks will push the limit to how far downfield they can without jeopardizing ball security.  Quarterback with low intended air yards will tend to score higher in IAY/PA – CAY/PA because they are taking less chances.

Analyzing The First QBS Metric – Completion %

Let’s look at Completion % as an example of how the QB Score for that metric is calculated:

1. We take the Average of all the data in the Completion % column.  This is 64.73%
2. We take the standard deviation of the data in the column.  The StDev is 5.00%
3. We use the Average and the StDev value to create the SD points awarded for the statistic

The unit of measure is Standard deviation units (StDev).  Very simply, StDev units measure how unusually good or bad a statistic is compared to the range it is in.  In mathematics:

• 68.26% of the data should fit within +/- 1 StDev unit
• 95.44% of a data range should fit within +/- 2 StDev units,
• 99.72 % within +/- 3 StDev units.

Remember the old Bell Curve that your teacher would use to adjust test scores?  The Bell Curve is simply a graphically representation of normal probability distribution.  That is a lot of mathematical jargon that boils down to the Bell Curve is showing Standard Deviation in picture form.  The greek letter sigma σ is the mathematical symbol for STDev Units.

Anything outside 2 SD above or below average is typically an Outlier.  These are scores/stats that are significantly better or worse than expected.  99% of all data should fit within 3 SD of average, so any SD value over 3.00 is an extreme outlier.

For example, Anthony Richardson’s Pass On Target % is 55.6% which scores an astronomically low -3.82 SD units.  This is somewhere between extremely improbable and slightly impossible.

SD Meaning
3SD+ Above Average = WOW
2 SD Above Average = Great
1SD Above Average = Good
Average = Average
1SD Below Average = Bad
2SD Below Average = Terrible
3SD Below Average or worse = WTF

Testing Completion % QBS Metric

Completion %  AVG – 64.73%  SD 5.00%
3 SD+ Above Average = 79.73% or more
2 SD Above Average = 74.73%
1SD Above Average = 69.73%
NFL Completion % Average = 64.73%
1SD Below Average = 59.73%
2SD Below Average = 54.73%
3SD+ Below Average = 49.73% and below

So let’s test this right off the bat.  How many completion % rates fall outside the +/- 2 SD range of 54.73% – 74.73%?

The answer is one, the aforementioned Anthony Richardson at 44.36%, a mind boggling -4.08 SD units off average.  Tagovailoa leads at 72.44%(+1.54 SD units), and Russell Wilson is next to last at 58.82%(-1.18 SD units).  Thus Richardson is a almost 15% points lower than the next to last quarterback in completion percentage.

Quarterback Types

QB Score has two components Pass Score and Rush Score; the sum is QB Score. Breaking out pass & rush scores really help identify and classify QBs into a handful of types.

Lamar Jackson is having a season that fits no type.  He is #1 in Pass Score(10.79), and #1 in Rush Score(4.92).  He leads pass score and rush score by almost 2 full points over the QB in 2nd position in each category, and he leads the overall score by nearly 6 points.

The amount of points he leads Purdy by(5.90), is more points than all but 4 Quarterback have in total: Only Purdy, Burrow, Darnold, & Murray have a QB score of more than 5.90 points.  While the range chart below quantifies him as a Pocket Passer, he should be listed as a Hybrid Runner.

Pocket Passer – Will have high Pass Score and negative or average Rush score. Purdy, Cousins, Goff are all this type.

Hybrid Passer – Will have mid range Pass and Rush Scores but pass will be relatively higher. Prescott, Stroud, Love would be this type of QB.

Hybrid Rusher – Will have a higher Rush score than pass score, though pass score will still be well above average. Hurts & Murray are the prototype for this group.

Pure Hybrid – This is a quarterback with both high pass and rush scores. Josh Allen and Patrick Mahomes(in a normal season for him) would be this type of unqualified hybrid.

Cagey Veterans – These guys usually have above average pass scores and fairly negative rush scores as age starts to limit their mobility. Stafford, Carr, Flacco, Mayfield, Geno Smith all fall into this category.

Run Around & Chuck It – These quarterbacks will have negative pass scores and positive rush scores. Fields, Richardson,  Watson, Caleb Williams all are in this group.

Walking Timebombs – This last group are the quarterbacks with both negative pass and rush scores, many with quite negative efforts in both categories. Minshew, Dalton, Winston reside here.

The Case for QB Score – QBS

For scoring, all we have to do is take the actual StDev value.  Do that for all 14 metrics, add them all up, and you get QB Score, or QBS.  The major difference being that, in QBS each QB is scored in each metric based on their performance AGAINST ALL OTHER QUARTERBACKS in that metric.  While it does matter what the quarterback did in the game on Sunday, it is also dependent on what all other QBs did on Sunday as well.

The second thing that makes QBS easier to understand and calculate, is that the average QBS score is literally 0.00 through 10 weeks.  That is pretty easy to remember compared to avg Passer Rating of 89.64 and an average 53.95 for QBR.  A quarterback with a positive QBS is performing above average, one with a negative QBS is performing below average.  Again pretty simple to use.

The third thing that makes QBS the better QB metric is that it has the smallest range of values.  The current range for QB is -12.09 to 15.70  Through Week 10, the current range for Passer Rating is 57.2 – 123.2, and the range for QBR is 22.4 to 76.8.  With QBS, using StDev of the QB Scores themselves, we can easily assign grades or performance buckets to the range.

The avg QB Score is 0.00, and the StDev is 5.90.

QB Score Interpretation

11.81+ = Exceptional
5.91 – 11.80 = Good to Excellent
0.00 – 5.90 = Slightly above average to Good
0.00 – -5.90 = Slightly below average to Bad
-5.91 – 11.80 = Bad to Horrible
-11.81 or lower = WTF?!

QB Score is a lot easier and clearer than either Passer Rating or QBR when it comes to figuring out what the number translates into with regards to summarizing the QB’s performance.  The chart below will help crystalize it.

QB Score vs Passer Rating vs QBR

The chart shows QB Score, Passer Rating, & QBR scores and ranks for every quarterback.  It is sorted by QB Score.

We can see each QB rating system has its quirks:

• QB Score seems to be overvaluing Sam Darnold & Geno Smith
• Passer Rating would appear to be overvaluing Jared Goff & Baker Mayfield
• QBR seems to be overvaluing Patrick Mahomes(if this is possible) & Trevor Lawrence

Some of this is going to be due to using only a half a season stats, which will be more volatile week to week.  Some is due to the components the rating system is using in the algorithm.  But it is probably fair to say that none of the three rating systems are bulletproof.

QB Score – QBS – for 2023

QB Score – QBS – for 2022

QB Score – QBS – for 2021

As with all the ratings and analysis, feel free to chime in via the post on Reddit/r/nfl, Practicalist on Reddit, or by sending an email.  Until next week, enjoy the football and best of luck to your team.

Passer Ratings Formula

The four separate calculations can be expressed in the following equations:

where

ATT = Number of passing attempts

CMP = Number of completions

YDS = Passing yards

TD = Touchdown passes

INT = Interceptions

If the result of any calculation is greater than 2.375, it is set to 2.375. If the result is a negative number, it is set to zero.

Then, the above calculations are used to complete the passer rating: