Accurate NFL Quarterbacks Aren’t Necessarily Great NFL Quarterbacks
Football fans, NFL executives, and the media often tend to laud quarterbacks with a high completion percentage as some of the best in the league. Drew Brees has recieved massive praise for his 2018 season, where he finished completing 74.1% of his passes. Sam Bradford and the Cardinals agreed on a lucrative $20 Million contract before the 2018 season, after he completed 71.6% and 74.4% of his passes in 2016 and 2017, respectively. (It is worth noting that he only played two games in 2017 due to injury, however.)
Most NFL followers would agree that Drew Brees is worth his lucrative contract, but Bradford did little to justify the investment the Cardinals made in him. He was cut before the conclusion of the 2018 season.
So can highly accurate quarterbacks be effective? Sometimes. But the majority of them are just good, not great. To prove this, I’ve conducted an exploratory data analysis. Materials used can be found in this GitHub repository.
Methods
I pulled the passing statistics from the entire 2018 NFL Season from pro-football-reference.com. Once converted into a .csv file, I uploaded the data into python using the pandas package.
After this, it became simple data cleaning. The goal of this cleaning process was to filter out any players with too small of a statistical sample to be included in the dataset. To get a more realistic sample, players with less than 10 starts and non-quarterbacks (multiple running backs and wide receivers threw a pass this season) were dropped from the data. This gave us a sample of 28 starting quarterbacks.
Analysis
The primary approach taken in this data analysis was to see if players who ranked amongst the top of the league in completion percentage were also leaders in other rating and efficiency stats. The top ten NFL passers in this data by completion percentage were as follows:
- Drew Brees — 74.4%
- Kirk Cousins — 70.1%
- Carson Wentz — 69.6%
- Matt Ryan — 69.4%
- Marcus Mariota & Derek Carr— 68.9%
- Deshaun Watson & Phillip Rivers — 68.3%
- Cam Newton — 67.9%
- Dak Prescott — 67.7%
However, only three of these players appeared in the top 10 of ESPN’s Total Quarterback Rating (QBR): Brees, Ryan, and Rivers. QBR is a metric that takes into account everything a quarterback does (passing, rushing, and turnovers mostly) and puts them on a 1–100 scale where 50 is average.
The average QBR of these top ten pass-completers is 63.3, a slightly above average rating. However, when you remove Brees, Ryan, and Rivers, it falls to a more paltry 58.8. What can we draw from this? Accurate quarterbacks are often above average players, but probably should not be considered “elite” unless they are proficient in other efficiency ratings.
Yards per attempt is an efficiency statistic designed to show us how many yards a quarterback is netting his team off of an average passing attempt. Only three quarterbacks appear in the top ten in both yards per attempt and completion percentage. Once again, it is Brees, Ryan, and Rivers.
This tells us that just because a player has a high completion percentage, it does not necessarily mean he is an effective quarterback. Players that are elite in this category are often not elite in other efficiency metrics such as yard per attempt, likely due to throwing a lot of short checkdown passes. These types of plays are effective for gaining small bursts of yardage, but don’t produce the explosive plays that create high-scoring offenses.
Conclusions
This data analysis indicates that most accurate quarterbacks are capable of leading an offense at a slightly above average level. However, a quarterback must be efficient from a yardage standpoint as well to be considered truly “elite”. Drew Brees, Matt Ryan, and Phillip Rivers are all good examples of players that met both criteria in the 2018 season.
Results of this exploratory data analysis also indicate that NFL General Managers should be more hesitant when giving money to a player like Kirk Cousins. Cousins completed his passes at a 70.1% rate this season, but only produced a 60.6 QBR. His fully guaranteed three-year, $84 million contract indicates he is paid similarly to Brees, Ryan, and Rivers, but he isn’t performing to the same level.
