Box score stats leave out a lot of crucial information. If we fix that problem by adding in essential data, how would the league’s quarterbacks stack up?
Passer rating (or quarterback rating, as it is sometimes called) is the most commonly used stat to compare quarterbacks against one another. It is an easy tool to use. Just put this guy’s rating alongside that guy’s rating and you can see who the better quarterback is.
However, I think most of the football community does not realize how bare of a statistic passer rating is. It has numerous flaws.
First off, a major part of the passer rating formula is completion percentage, an almost completely meaningless stat. Completing a pass does not mean anything in a vacuum. A completion could go for 99 yards or zero. All that matters is the overall production on a per-play basis. Completing 100% of passes means little if the quarterback averages 4.0 yards per attempt. Completing 50% of passes is perfectly acceptable if the quarterback averages 9.0 yards per attempt.
Would you rather have a 50% shooter who only makes two-pointers or a 40% shooter who only makes threes? Would you rather have a .300 hitter who only hits singles or a .250 hitter who only hits doubles and homers? Completion percentage and stats like it are silly. There is a massive range of impact that a completion can have – they can even be negative – so giving a quarterback credit just for completing a pass without taking into account what they actually got out of it makes little sense.
Give me Patrick Mahomes‘ 20th-ranked completion percentage (66.9%) and sixth-ranked yards per attempt rate (8.17) over Cam Newton‘s sixth-ranked completion percentage (68.8%) and 20th-ranked yards per attempt rate (7.38) all day.
Secondly, passer rating does not include rushing production or sacks, two massive parts of a quarterback’s game. Of the league’s 35 quarterbacks with at least 100 passing attempts this season, rushing attempts and sacks have made up 14.5% of their total plays and 12.2% of the total yardage they have contributed to. That is a huge chunk of production left unaccounted for, especially for run-heavy quarterbacks like Kyler Murray and Lamar Jackson.
The ability to produce first downs is among quite a few other aspects of quarterback play that passer rating does not account for. A two-yard pass can be positive if it moves the chains on fourth-and-2. A 20-yard pass can be relatively meaningless if it comes on third-and-30. These are things that fly under the radar in the box score.
Look, I like passer rating for how easy it is to access and utilize. I refer to it a lot. If you are just looking to quickly make a simple comparison or get a one-number glimpse at a decent approximation of how well someone has produced, it’s useful. But if you want to know the truth, you have to dig deeper.
There are a few great advanced metrics out there that account for all of the things that passer rating does not. Football Outsiders’ DVOA throws in contextual information such as down, distance, field position, score, time, and opponent quality to deduce the true value of every play. ESPN’s QBR is an all-encompassing quarterback metric that accounts for many of the same things as DVOA while also tossing in factors like drops and pressure.
While those metrics are fantastic, I wanted to look solely at the box score and figure out a way to get the absolute most out of the simple, raw data that is available. How would the quarterback leaderboard look if we included every important box score stat that is tracked?
The four factors of passer rating are yards per attempt, completion percentage, passing touchdown percentage, and interception percentage. By mixing in stats such as passing first downs, rushing yards, rushing touchdowns, rushing attempts, rushing first downs, sacks, sack yards, and fumbles, I was able to improve the viability of those four core factors and concoct a much more accurate version of passer rating.
Let’s see where Sam Darnold and Joe Flacco rank when we take everything into account.
Yards per play
I’ll break down each of the four factors in my revised passer rating metric before getting into the final pecking order. We begin with yards per play.
I am a fan of old-fashioned yards per attempt (Y/A), but it leaves out yards from sacks and rushing yards.
Sacks are more of a quarterback stat than an indication of offensive line play since most sacks can be avoided in one way or another. The offensive line is responsible for the total amount of pressure allowed – extremely important – but the sacks themselves tend to be a product of the quarterback’s style. Ryan Fitzpatrick has played behind some bad lines, but his sack rate is usually low since he is a gunslinger who would rather chuck an ill-advised bomb than take a sack. Hence, his turnover propensity. On the other end of the spectrum, you have guys like Carson Wentz and Deshaun Watson who have taken a lot of sacks while attempting to extend plays.
So, sacks are an important part of quarterback play and should be evaluated as such. Quarterbacks deserve blame for taking too many sacks and they also deserve credit for avoiding them.
With yards per play, we throw in rushing yards and sack yards to get a look at the average amount of yards that each quarterback has produced across all of their plays, not just passing attempts.
Here is a look at how the league’s 35 qualified quarterbacks (100+ passing attempts) stack up in terms of yards per play. The results for Darnold and Flacco are telling.
Formula: (passing yards + rushing yards – sack yards) divided by (passing attempts + rushing attempts + sacks)