NFL Draft: Which Statistics Matter When Evaluating Quarterbacks?

North Carolina v Georgia Tech
North Carolina v Georgia Tech / Kevin C. Cox/GettyImages

With the college football season coming to a close, it’s time for us football junkies to turn our attention to the 2024 NFL Draft. The next few months will be a ton of fun as fans and analysts watch all oof the prospects they can to figure out who the top players in this year’s draft are and who each team should target.

Generally speaking, many analysts evaluate prospects by watching their tape. This is an important part of the evaluation process because this shows you what a player’s strengths and weaknesses are and it gives you insights into how a player produces and whether or not their playstyle translates to the next level.

The tape isn’t the only thing that’s important to look at, though. It should definitely be a part of your evaluation process, but you should also look at a player's production. The more information you have, the better your evaluations will be.

With that being said, let’s take a deep dive into quarterback stats and see which metrics are useful for evaluating quarterback prospects and which ones aren’t.

It’s important to isolate a quarterback’s individual performance

The most important thing you have to do when breaking down a quarterback’s production is to avoid stats that don’t tell you anything about a player’s individual performance. This involves ignoring stats that are noisy and heavily impacted by a quarterback’s scheme and supporting cast.

The biggest example of stats that are noisy is counting stats like passing yards, passing touchdowns, and interceptions. These metrics provide some value, but they are impacted by a quarterback’s surroundings. If a quarterback plays in a bad offense, they likely won’t have a ton of opportunities to throw touchdowns. If they play in a run-heavy offense, they won’t record as many passing yards. Sometimes quarterbacks get unlucky and they have fluky interceptions that aren’t their fault. Unfortunately, this won’t be accounted for in their interception total.

All of this is why counting stats are a very flawed way of evaluating quarterbacks. They’re like a portrait that’s blurry. You can see the whole picture but you can’t see all of the little details and you might miss some blemishes.

Building off of this, it’s important to know if a quarterback’s coaching staff is setting up their offense in a way that manufactures production for the quarterback. Teams can do this by using a lot of play-action or running a lot of screens. These types of plays exist to generate easy offense. If a quarterback is productive and efficient but his team runs a lot of these types of plays, this can be a good reason to pause and consider whether or not his numbers are indicative of how well he is playing.

PFF has some great data for quarterbacks that are based on their tracking of the film. A lot of their stats are subjective and many people have an issue with that. However, their stats provide a lot of information that attempts to isolate a quarterback’s performance. Because of this, their data is extremely valuable. Let’s look at some of their incredibly useful for measuring quarterbacks’ performance.

Accuracy, Accuracy, Accuracy

PFF has a stat called adjusted completion percentage which measures the percentage of a quarterback’s throws that are considered accurate or on-target. This improves upon completion percentage which tells you whether or not a pass was complete, but not if the throw was actually accurate.

Accuracy is an important skill for any quarterback to have. Being able to process a defense is great, but it doesn’t matter if you can’t deliver the ball accurately. Another thing to consider when looking at this stat, though, is how difficult a quarterback’s throws are. 

One way you can adjust for this is by looking at a quarterback’s average depth of target (aDOT). This matters because the more deep throws a quarterback attempts, the lower their accuracy rate will be. On its own, aDOT is more of a team stat than an individual stat, but it provides context when you look at other metrics like adjusted completion percentage.

Sack avoidance is criminally underrated

One of the most important skills a quarterback can have is the ability to manage the pocket. Football nerds have done plenty of research into whether quarterbacks or offensive lines bear the responsibility for sacks and the research is clear that quarterbacks bear more responsibility for their sacks than we previously realized.

When you look at the top quarterbacks in the NFL, a lot of them are great at managing the pocket and avoiding sacks. A stat that measures this skill is pressure-to-sack rate, which measures the percentage of a quarterback’s pressured dropbacks that result in a sack. With this stat, the lower the number, the better.

When quarterback prospects are good at avoiding sacks, this is evidence that they have great football instincts and it can allow them to extend plays even if they aren’t great scramblers. It can also allow them to generate big plays at a higher rate.

Like with adjusted completion percentage, it’s important to consider some context when looking at a quarterback’s pressure-to-sack rate. Stats like aDOT and average time to throw will provide important context because it’s really impressive if a quarterback can avoid sacks while attempting a lot of deep passes and holding the ball for a long time.

Elite quarterbacks are really good under pressure

It’s no surprise that great quarterbacks often perform extremely well when opposing defenses get into the pocket and put pressure on them. Players like Patrick Mahomes and Josh Allen consistently excel in this area.

When evaluating a quarterback’s performance under pressure, it’s important to look at a stat that includes their passing and their rushing. PFF grade is the best way to go because the publicly available data on PFF’s site does not include quarterbacks’ rushing numbers when under pressure. However, PFF’s grading will include this part of a quarterback’s game.

It’s important to know that PFF grade is a metric that PFF creates by watching and grading every single play. It’s extremely subjective and it doesn’t give you many details about a quarterback’s performance, but it does a good job of measuring how good a quarterback has been under pressure. Adjusted completion percentage and pressure-to-sack rate are also important to consider when evaluating a quarterback’s ability to handle pressure.

Passing is king, but rushing is closer than you realize

Over the last couple of years, it has become increasingly apparent that rushing production is more important for quarterbacks than we previously realized. It is still more important for a quarterback to be able to throw the ball at a high level, but recently we’ve seen quarterbacks who aren’t great passers lead efficient offenses primarily because they were good rushers.

During the 2022 NFL season, Jacoby Brissett and Marcus Mariota led above-league-average offenses with the Browns and Falcons respectively, but neither were very productive passers. The reason why their efficiency metrics were above league average is because they were both productive rushers, ranking top fifteen among quarterbacks in rushing yards per game. A quarterback doesn't have to be a great passer to generate efficient offense. They can do it with their legs!

Let's take a look at some of the top quarterbacks in the league, like Patrick Mahomes, Josh Allen, and Lamar Jackson. All of these guys are some of the best passers in the league. Yes, that includes Lamar you haters. Anyway, these guys sling the football better than most quarterbacks on the planet, but what separates them from other great passers is their ability to make plays on the run.

Interestingly, all three of these quarterbacks were imperfect in college. They had major question marks, and Allen specifically had an extremely underwhelming statistical profile. Do you know what all three players had in common, though? They had amazing physical tools and could run. All three quarterbacks averaged over 35 rushing yards per game throughout their collegiate careers, with Jackson averaging a ridiculous 126.1 rushing yards per game.

The best quarterbacks in the NFL have some level of rushing ability even if they don't run the ball themselves. They often scramble a decent amount and extend plays outside of structure. This doesn't mean that all rushing quarterbacks are good, it just means that quarterbacks who can scramble can provide value even if their passing ability is not up to par. Trust me, you should care about a quarterback prospect's production as a runner.