Analytics, Basic Stats, and Recent Historic Context: The ABC’s of Penn State Football – The Brent Pry Era: Part 2
Introduction
Welcome to Part 2 of our in-depth look at Penn State’s defense since the promotion of Brent Pry to Defensive Coordinator in 2016. In Part 1 we analyzed the Nittany Lions’ performance in standard statistical categories and compared those numbers against the rest of the Big Ten over the past 5 seasons (2016 – 2020). The main takeaway was that the “bend, don’t break” reputation that the Penn State defense has earned recently is deserved. Pry’s group tends to give up a fair number of total yards but does an excellent job of preventing teams from scoring and limiting big plays (the low YPP). Additionally, Pry’s teams have been better than average on 3rd down and generating Havoc plays in the form of sacks, tackles for loss, and fumbles.
Today, we will take a deeper look at the defensive performance in some of the more advanced statistical measurements. Again, all stats herein are only for conference games from 2016-2020.
Defensive Efficiency
Let’s start with Defensive Efficiency (essentially, offensive yards allowed per drive) which is a somewhat more granular measurement than Total Defense and can really reinforce the concepts and trends illustrated in Part 1. Below is Penn State’s per drive allowed yardage by season since 2016. As you’ll see, Penn State’s year-by-year marks all fall in a very tight range of 26-28 yards allowed per drive. These are all consistently better than the conference mean average performance of 29-32 YPD, depending on the season. By season, Penn State ranked 6th, 7th, 4th, 6th, and 3rd in Defensive Efficiency. Anyone else as surprised as I am to learn the best performance of the last 5 years was the 2020 team?
Now, let’s compare those rankings to Penn State’s Scoring Efficiency (points per drive) allowed with Pry at the helm of the defense. In that time, the Lions finished 6th (2016), 3rd (2017 -2019), and 6th (2020). From 2017 to 2019, Penn State’s Scoring Efficiency outperformed its Yardage Efficiency in league rank.
Against the mean, the allowed yardages were always better but typically, except for 2020, no more than 10% better. The allowed points per drive were always >10% better than the mean with the best performance being 2019 which was nearly 40% better.
Once again, Advanced Stats confirm the bizarre nature of Penn State’s 2020 season. Consider this: The Nittany Lions posted their best Yardage Efficiency numbers in five years AND their worst Scoring Efficiency numbers in five years last season. As mentioned in Part 1 though, this is likely as much a function of the offense putting the defense in terrible positions, or the offense straight up surrendering scores via pick-6’s and fumbles returned for touchdowns, as the defense’s own troubles.
Below is the combined plot of yardage and scoring efficiency for all Big Ten teams’ individual seasons since 2016. While the Lions haven’t been at the top of the league in either category, it is interesting to see just how consistent they’ve been. Except for the 2020 scoring outlier, the Lion logos are well grouped together. Pry’s defenses represent a model of consistency that really no other team has shown. Now, they just need that one breakout season.
Explosivity
We calculate the Explosivity of a defense by the number or point-yards (points*yards) they give up per 100 plays on a per game basis. It may not seem terribly intuitive but let’s look at an example. A team scores a touchdown (7 points) that travels 80 yards. That leads to 560 point-yards. If that happens in 1 play, that team’s Explosivity would be 5.6 (7*80/1/100). If it took that team 10 plays, then they would have an Explosivity rating of 0.56. Therefore, the lower the number the better job a defense is doing since they’re not giving up big plays and quick scores. Got it? Good.
Well, Penn State’s defenses have been quite good in this category, always outperforming the league average with 2019 being the best performance (0.7 Explosivity allowed). It is surprising to me that the 2019 defense rates out so well in retrospect. Again, as with scoring efficiency, 2020 was a down year and yielded the lowest (highest?…worst, let’s go with worst) performance of Pry’s tenure. But on the bright side, the performance in 2020 improved throughout the year and the 2nd half (0.85 average Explosivity allowed) looks dramatically different than the first half (1.91 average).
Overall Effectiveness
Finally, let’s end Part 2 of our statistical retrospective of the Brent Pry Era at Penn State by examining the Lions’ Overall Defensive Effectiveness. Here, we combine allowed ball control (yardage efficiency and allowed time of possession) with Scoring Explosivity (points allowed per minute). This yields a value where, for a defense, lower is better. Out of the 2k plus words and 15 or so plots over these last two articles, the chart that brings it all together is the one below.
It shows that on whole, despite some minor weaknesses in individual categories in individual seasons (interceptions, 3rd down conversions allowed) Brent Pry is a fantastic coordinator who knows how to put his talented players in great positions to succeed. Penn State has continually (except for 2020) outperformed most of the league and finished 2016 (5th), 2017 (6th), 2018 (3rd), 2019 (3rd), and 2020 (6th).
If we look at the data on a team-by-team basis, we see the consistency of the Lion defenses against the rest of the league. Pry’s defenses have not quite yet had an exceptional season like 2016 Michigan, 2019 Ohio State, or 2019 Iowa (all Overall Effectiveness below 13) but they also haven’t posted any putrid seasons like 2020 Michigan, either.
If Penn State’s average Overall Defensive Effectiveness (20.2) under Brent Pry continues to reside in the same neighborhood as Iowa (17.1), Ohio State (18.3), Wisconsin (19.3), and Michigan (19.8) then the Lions should have a great chance for success in any game and any season.
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