Baugh about to complete a pass, probably.

Let’s take completion percentage. The passer rating formula measures completion percentage by taking a passer’s completion percentage, subtracting 30%, and multiplying the result by five. This made sense when the average completion percentage was around 50%; in that case, 50% minus 30% equals 20%, and multiplying that by 5 gives a result of 1.00.

To adjust for era, we replace “30%” in that formula with “league average minus 20%.” So in 2018, the league average completion percentage was 64.9%, which means we would use 44.9% for this formula. Drew Brees completed 74.4% of his passes; if we subtract the baseline from his result, we get 29.5%. Multiply that result by 5, and Brees gets a completion percentage score of 1.48 for 2018.

If we do this for every quarterback in every season of his career, and then weight each season by his number of pass attempts, we can get career grades. This is one way to come up with career completion percentages adjusted for era.

The overwhelming champion in this regard is Sammy Baugh, who led the NFL in completion percentage 8 times during the decade of the ’40s. As recently as 1975, Baugh was still 4th all-time in career completion percentage, and less than 1% off of the leader. Baugh has a rating of 1.58, which means on average he was better at completing passes relative to his era than Brees was in 2018.

The top passers in measuring completion percentage this way are Baugh followed by a who’s who of the completion percentage kings: Len Dawson, Otto Graham, Steve Young, Joe Montana, Sid Luckman, and Drew Brees.

The bottom 5? Rex Grossman, Jay Schroeder, Doug Williams, Mike Pagel, and the man at the very bottom of the list is… Derek Anderson.

The table below shows the 189 passers with 1,500 career pass attempts. Here’s how to read the table below: Baugh has the best adjusted completion percentage, and he threw 2,995 career attempts. He played from 1937 to 1952, and has an era-adjusted passer rating of 92, which ranks 3rd. He has a completion percentage grade of 1.58. The final column? That shows Baugh’s completion percentage grade relative to the other 3 variables in the passer rating formula (Y/A, TD%, and INT%). So Baugh is +0.27 better in completion percentage than the other 3 metrics, on average.

In some ways, it’s that last column that is most interesting to me. Completion percentage is significantly overstated in the passer rating formula, so if a player is much higher in completion percentage than in their average of the other three metrics, it’s very likely that passer rating overstates their true value. So let’s break the groups into those whose passer ratings are inflated by strong completion percentages and those whose ratings are deflated by weak completion percentages.

Boosted By High Completion Percentages

Frank Tripucka is your leader here, followed by Sammy Baugh, Ken Stabler, Chad Pennington, Troy Aikman, Brian Griese, Bart Starr, Drew Brees, Tim Couch, and John Brodie. It’s an interesting group of players: Tripucka and Couch still have below-average passer ratings (66.7 is average) despite strong completion percentages, while Griese, Brodie, and Aikman were basically average other than their stellar completion percentages. Meanwhile, Stabler and Pennington were efficient passers who happened to be best at completion percentage, and that goes triple for guys like Baugh, Brees, and Starr. Pennington was a very good quarterback, but his 29th-place ranking in passer rating is more a function of how the formula tips the scales in favor of high completion percentage.

Harmed By Low Completion Percentages

Doug Williams is the biggest outlier here, and he had a very low sack rate which helps to explain his low completion percentage. Other players who were much better in Y/A, TD%, and INT% than completion percentage include Jay Schroeder, Michael Vick, Derek Anderson, Frank Ryan, Daryle Lamonica, Colin Kaepernick, Aaron Brooks, Don Meredith, Mike Pagel, and Terry Bradshaw.

Vick is another interesting choice. Did you know that from 2001 to 2013 he led all players in yards per completion but he ranked 46th out of 50 passers in completion percentage? Vick also replaced a lot of easy, 5-yard completions with 5-yard scrambles (or longer), which artificially deflated his completion percentage. Some of that probably applies to Colin Kaepernick, too, and his case is even more interesting because of his remarkably low interception rate juxtaposed against his low completion percentage. Lamonica and Ryan were two HOF caliber passers who are underrated when you examine completion percentage: how much differently would we view their careers if they had slightly lower Y/C averages and higher completion percentages?

What stands out to you?

Do you know the answer? I’ll give you a couple of moments to think about it. First, a graph showing the 200 players with the most pass attempts in NFL history (all have at least 1,325 attempts). On the X-Axis is completion percentage; on the Y-Axis is Yards per Completion. There are no era adjustments here, which can also make it kind of fun: over time, completion percentages have skyrocketed, while the average yardage gained per completion has decreased. As a result, a player with a very high yards per completion percentage almost certainly played long ago, and therefore has a low completion percentage (and vice versa). Take a look:

In this graph, I have put nine of the data points in red. Those points are the Pareto Efficient quarterbacks: there is not even one passer in NFL history who has both a better completion percentage and a better yards/completion average than those players.  Who are they?

Let’s start from the top. Ed Brown played for the Bears in the ’50s and the Steelers in the ’60s. He led the NFL in yards per completion in ’56 and also ’63, and had other sky-high yards per completion seasons (like 1960) where he failed to have enough pass attempts to qualify for the crown.  Brown retired in 1965 as the career leader in yards per completion at 16.4; he remains the career leader, and it’s never going to change.  Steve Beuerlein (12.7 yards per completion) has the highest career Y/C average among players who were active in the 21st century; Cam Newton (12.5) and Jameis Winston (12.4) are highest among active players, but nobody is ever going to knock Brown out of the record books.  As a result of being the career leader in yards per completion, he will be Pareto Efficient regardless of his completion percentage.  That said, he had a pretty bad completion percentage even for his era: his first three years in the NFL he had a great completion percentage teaming with Harlon Hill, but for the rest of his career his completion percentage was pretty ugly.

After Brown we get a stretch of Hall of Fame passers. Another Bears quarterback, Sid Luckman, is second all-time in yards per completion at 16.2, and his 51.8% completion percentage was better than Brown’s 47.8%.  Third on the all-time Y/C list at 16.1 is Browns great Otto Graham (AAFL stats included), and he (55.8%) had a better completion percentage than Luckman.

We have to drop about 30 spots on the yards/completion list to get to another quarterback with a better completion percentage than Graham. That man was Packers legend Bart Starr, who completed 57.4% of his passes and averaged 13.7 yards per completion.

Next up is Chargers icon Dan Fouts, who averaged an even 13 yards per completion but at a 58.8% clip.  Fouts is remembered as a quantity guy and a deep thrower, and he currently sits 62nd on the career completion percentage list. But when he retired in 1987, he ranked 7th on the career completion percentage leaderboard, including behind two guys who entered the league in 1983.

Now, do you remember the trivia question at the top of the post? Next on the Pareto Efficiency list is our first entrant with a completion percentage north of sixty. He completed 60.6% of his passes and still averaged 12.6 yards per completion.  Even at the 1,000 attempt mark, he is the only player in NFL history to complete at least 60% of his passes and average 12.5 yards per completion. That man is Trent Green, who spent the bulk of his career with the Chiefs.  In Kansas City, Green completed 61.9% of his passes and averaged 12.48 yards per completion; outside of KC, he completed 56.7% of his passes and averaged 12.85 yards per completion, with his time with the Rams being his most productive.  Green may not have been as good as his numbers indicated, but he does stand out in this list of Hall of Famers.

Up next is another all-time great in Steve Young – he averaged 12.42 yards per completion, but where Young really stands out is his 64.3% completion rate. Twenty years ago, Young was the clear king of this stat, but he has now dropped to 9th on the list.

After Young is Kurt Warner, who is third on the career completion percentage list at 65.5%.  Despite that, Warner has a still impressive 12.1 yards per completion average; he, of course, like Green, played on talent rich teams which boosts his career rate stats.  But with a 7.95 yards/attempt average, Warner ranks fifth (behind Graham (8.98), Luckman (8.42), Van Brocklin (8.16), and Young (7.98)) on the career Y/A list.

Finally, the last name on the list is the bookend to Ed Brown: by virtue of being the career leader in completion percentage, Drew Brees has to be Pareto Efficient.  Brees has a very low (by historical standards) 11.3 yards per completion average, which makes him a true counter to Brown.

And that’s it: those are the 9 men in NFL history who have such a good completion percentage and/or yards/completion average, that no player in history was better at them in both categories.