Evaluating CFB QB's: 2021 QB Composite Scores
Efficiency, accuracy, tape based evaluations.... all together into one!
Evaluating the QB position in football is an arduous process that we are trying to improve each and every day. In the modern game of football, if you don’t have the right QB, your ceiling as a football team can be very limited. Before the season, I took a look at some QB metrics that you could use in your own personal evaluations of QB’s. Today, we are going to look at some of those metrics and create a QB composite score of the most meaningful variables.
The inspiration behind this QB Composite score comes from Tej Seth, a highly skilled intern at PFF. He has kept a composite score of QBs for the NFL this season, with the metrics used in the tweet below:
Our QB Composite score will have a similar make up as the one Tej has put together, but will a couple key differences. The metrics used in the CFB QB Composite Score are as follows:
Expected Points Added (EPA) per play: This will serve as our raw per play efficiency metric. There are no defensive adjustments to EPA/Play, so this will be our look at how well a QB performed regardless of who was lined up against him.
ESPN QBR: QBR is essentially an EPA/play type metric that adjusts for defense. QBR is one of the most stable metrics year to year, and will be our way to identify which QB’s were either positively or negatively impacted by the strength of the defenses they faced. If a QB has a high EPA/Play but a lower QBR, it could be due to a weaker defensive schedule.
Completion Percentage Over Expectation (CPOE): If you want a more in depth look into what powers the CPOE model, I highly suggest reading this piece over at PFF. The TLDR version of CPOE is an evolved form of completion percentage. Completion percentage does not take into account how far the pass traveled in the air, or if the receiver was open/covered. CPOE does take this into account and more, and estimates the probability a pass will be completed. For the purpose of our composite, CPOE will judge a QB on his accuracy in any situation.
PFF Grade: Despite the reputation as a data driven/hyper analytical company, at its core PFF grades are tape based metrics. Essentially each play is reviewed and given a grade. After an adjustment based on historical expectations, we have a PFF grade. While there is some number crunching involved, at its core PFF grades are tape based, so they will serve as your tape based metric.
Each of these variables will be weighted by how much they predict the most stable public metric we have, ESPN QBR. Once we have our composite, it is then set to a 0-100 scale for easier digestion.
2021 CFB QB Composite Score Top 25
The top QB in the composite score hails from #OurChants, Grayson McCall. After an injury to McCall and a pair of losses, the Chanticleers took a step back from the national spotlight they occupied in 2020. Even with the injury, McCall and Coastal Carolina ran their high powered option offense at will against opponents. They earned high marks in nearly every efficiency and explosive play metric you can find. It remains to be seen whether McCall will return to Coastal Carolina for one more season, but if he does, expect even more explosive fun from the lovable Chants.
This season we have heard numerous stories on the Bryce Young’s the Kenny Pickett’s and the Caleb William’s of the CFB world. One QB we really didn’t hear much about was Purdues Aidan O’Connell. O’Connell was a 5th year senior that battled injuries and wasn’t the consensus starter to start the season. He blossomed into a top 5 QB this season, and due to the Covid year, will get a chance to come back for a 6th season. If he can continue to maintain this level of efficiency, you will hear a lot more about the Purdue “Spoilermakers”.
NFL Draft Prospects
Prospects still have time to decide whether they will declare for the NFL draft or return for another season, so some of these names may not put their name in the ring. Nevertheless, these are the names that seem to be the more popular names in draft circles. Pittsburgh QB Kenny Pickett has helped his draft stock arguably more than any other QB this season. Pickett has gone from a draft hopeful to a potential first round pick, while helping Pitt win an ACC championship along the way.
North Carolina had a disappointing season given their preseason expectations. Still, it would be odd to consider a 90 offensive PFF Grade and 24th ranked composite score a disappointment for Sam Howell. There were moments of brilliance and moments of disappointment, but overall it wasn’t a bad season for Howell. It will be interesting to see what his evaluation is during the pre draft process, which is something you can say for most of the QB’s on this list.
Composite Scores By Draft Class
Since we don’t know for sure how is declaring for the draft or staying, another way we can look at the present and future is by comparing composite scores by the QB’s draft eligible year (3 years post high school). An interesting trend you can see from this graph is the tightness of each cluster. As you move right to younger QB’s, you can see one or two QB’s breaking out while some still need to take another step forward.
Oklahoma QB Caleb Williams lit the CFB world on fire when he replaced preseason heisman favorite Spencer Rattler against rival Texas. Although there were some bumps and bruises along the way, overall Caleb Williams was electric and poised to be one of the top QB’s in his draft class. In the 2023 QB draft class, Bryce Young has locked in the QB1 spot for now, and has the potential to become a rare two time Heisman trophy winner. However, he may be threatened by upstart Miami QB Tyler Van Dyke, who took over for the injured D’eriq King and put up monster numbers in relief.
QB Usage: Power 5
To wrap this up and to get a look at all of the QB’s in one plot, we can plot composite score against offensive usage rate to get a look at which QB’s were perhaps underutilized in their offense. Usage rate is essentially just how many snaps the QB was involved in during the season. QB’s above the line were potentially being underutilized in their specific offensive scheme, while QB’s below were most likely being asked to do too much.
DJ Uiagalelei had the impossible task of following both Deshaun Watson and Trevor Lawrence as the QB for Clemson. His first season at the helm was one to forget. However, he is still a young QB and has time to develop and take the next step forward. Incoming 5 star Clemson signee Cade Klubnik could threaten his job as QB1, and there is always the possibility of a transfer coming into the fold. Regardless, don’t count out the former 5 star just yet.
Georgia QB Stetson Bennett was not asked to do much behind an elite defense and run game. When he was asked to perform, he was highly efficient, and one of the reasons Georgia was able to cap off an undefeated regular season. Of course, the SEC championship reopened the conversation of whether he was able to provide the Georgia offense with that extra spark needed to win a championship. Bennett was responsible for 21 Expected Points lost to sacks and turnovers, which ultimately doomed the Bulldogs. Georgia still made the CFB playoff, and has a semifinal date with Michigan looming. It remains to be seen what changes Kirby Smart makes on offense, and whether those changes mean a change at the QB position.
QB Usage: Group of 5
Western Kentucky’s approach this season was to bring in the Houston Baptist offense and see if they can get it to work on the FBS level. The end result was QB Bailey Zappe throwing for nearly 6,000 yards, 56 TD’s and finishing 11th in the QB composite score. That doesn’t even include Western Kentucky clinching a spot in the Conference USA championship game, their first appearance since 2016. The transfer portal is still a relatively new tool in the CFB landscape, but the Hilltoppers 2021 season falls squarely in the “successful” bucket.
From Carson Strong and Malik Willis to Tanner Mordecai and Frank Harris, there were numerous group of 5 QB’s that made their mark on the season. 8 of the top 25 QB’s in the composite score hail from G5 schools, and nearly all of their teams saw success in the form of double digit wins or conference championship appearances. The rise of the transfer portal era will bring about more success stories like the ones above, and will make games outside of your own bubble more enjoyable to watch.
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