We've talked a lot throughout the course of this season about our frustrations with Georgia Tech's defense. While the offense has definitely improved since the start of the season, the defense has slowly degraded and become less and less reliable. After giving up 57 points in the team's first four games (14.25 ppg, with only Clemson scoring more than 14), the defense has allowed 117 points over its last four (29.25 ppg, not including the defensive touchdowns scored by Miami), including 96 points to the most recent trio of Pittsburgh, Georgia Southern, and Duke.
I should clarify, too, that the issue here isn't personnel or talent -- it's scheme. That likely won't come as a shock to many, but in case you're the type who thinks that recruiting to that side of the ball is causing the issues, let me explain.
Ted Roof runs what is traditionally referred to as a "bend, don't break" style of defense. It aims to eliminate big plays from the opposing offense, and forces them to be patient and run more plays without making mistakes. When mistakes are made, the defense can pounce and either create turnovers or stall out a drive before the offense manages to make it into the end zone. It's not inherently a poor scheme -- it makes a lot of sense in today's world of up-tempo, spread offenses that often involve a lot of passing, where a single tipped ball or misplaced pass could turn into an interception. (It also works better for college than professional football, where errors are far less common.)
Where the scheme breaks down (and where Georgia Tech's defense has been so bad lately) is when the offense makes those mistakes, and the defense isn't in position to capitalize. That could be simple things like how corners are lined up against opposing receivers, or larger things like defensive personnel and playcalling used on third-and-long. When the defense can't capitalize on offensive mistakes, "bend, don't break" becomes "death by a thousand cuts, eventually resulting in giving up a lot of points".
This isn't an issue of talent on that side of the ball -- the talent is there. This isn't an issue of players being fundamentally unsound or not athletic enough to succeed. It's an issue of players being out-of-position to capitalize on mistakes, having their eyes in the wrong places, and being unable to play full-speed because they're not comfortable with their assignments. That’s an issue of coaching and scheme.
Let's look at some numbers that further illustrate the issues on defense. We'll even use a mix of standard and advanced metrics, in case any Atlanta media members need help deciphering the difference between successful defenses and unsuccessful ones.
Georgia Tech's Defense: 1 sack/game
National Rank: 122 (of 128)
Power-5 Rank: 64th (of 65)
Georgia Tech's defense had three sacks in all of October -- none against Miami, and one in each game against Pittsburgh, Georgia Southern, and Duke. They have exactly one sack in every game so far, except for games against Miami (again, none) and Mercer (two sacks!)
We can also adjust for pace and opponent styles here, and point out that Georgia Tech is 120th nationally with a 2.86% sack rate. (In other words, they're achieving less than 3 sacks per 100 QB dropbacks.)
Third Down Conversions
Georgia Tech's Defense: 50.88%
National Rank: 128th (Dead Last)
Power-5 Rank: 65th (Dead Last)
Yeah. Georgia Tech is dead last in the country in allowing third down conversions. It's at the point where an opposing offense has a better chance of converting any third down (regardless of distance) than you do of flipping a coin and having it turn up heads. For reference, the national average is around 38.5%, and Virginia Tech leads the conference at 25.21%. (For those keeping score at home, that's less than half of the third-down conversions that Georgia Tech allows.)
Georgia Tech's Defense: 11.1%
National Rank: 125th
Power-5 Rank: 64th
This is a more advanced metric, defined as percentage of plays that end with a tackle for loss/sack, a pass knocked down/intercepted, or a fumble forced. Given the total lack of involvement that the linebackers and secondary tend to have in coverage before a pass is completed, and the total lack of involvement of the linebackers in supplementing the pass rush, this is hardly a surprise. (This is another example of how a "bend, don't break" defense should be able to capitalize on mistakes, but Georgia Tech's just can't.)
For reference, the national average is around 16%, and Virginia Tech also leads the conference in this stat at 22.5%. (That's #3 nationally.)
Defensive Success Rate
Georgia Tech's Defense: 45.4%
National Rank: 103rd
Power-5 Rank: 56th
This was referenced a couple of weeks ago in my column where we analyzed Georgia Tech’s first-half performance through the lens of its S&P+ numbers. Success rate is a measure of how efficient an offense is, or how good a defense is at rendering its opponents’ offense to be inefficient. Simply put, it’s a measure of whether the offense is staying ahead of the chains, or whether a defense is keeping opposing offenses behind the chains. It’s a hard percentage of plays, where successful plays are defined as those where the offense gains:
- 50% of the necessary yards-to-gain on 1st Down
- 70% of the necessary yards-to-gain on 2nd Down
- 100% of the necessary yards-to-gain on 3rd or 4th Down
National average is typically around 40%, and currently at 40.9%. Georgia Tech’s opponent are currently 4.5% more efficient than the national average, and there are 102 teams with more efficient defenses.
Georgia Tech's Defense: -0.62
National Rank: 109th
Power-5 Rank: 61st
Again, we’ve talked a lot over the past two weeks about S&P+ ratings. Let’s talk about the other side of the F/+ ratings, Brian Fremeau’s FEI system. The difference is that S&P+ is more concerned with play-by-play data, where FEI takes a step back and considers drive-based data and outcomes. It’s opponent-adjusted and is more concerned with the outcomes of drives than how a team gets there, effectively. Georgia Tech is currently #9 in offensive FEI, which is really good!
Georgia Tech is currently #109 in defensive FEI, which is really, really bad. Regardless of how opponents are getting there, the defense is breaking eventually.
How is this improved?
Realistically, small tweaks could go a long way. They could change things like...
- The secondary is consistently lining up behind the line-to-gain on third downs, seemingly regardless of how much needs to be gained. That has to stop. This helps to reduce third-down conversions.
- The pass rush began being supplemented with linebackers and safeties over the last two games. That has to continue. This helps to supplement the sack and havoc rates, and success rate.
- The cornerbacks are consistently giving 7-8 yards of cushion to receivers. Move them another 2 yards closer, so that they’re in position to knock down passes or create turnovers. This helps havoc and success rates.
- Coverage match-ups need to be paid attention to, especially in short-yardage and goal line situations. (If 5’9” Lance Austin is shown covering 6’5” Bug Howard this weekend, I’m going to scream.) This helps to reduce third-down conversions, increase havoc rate, and decrease success rate.
- Packages need to be leveraged in relevant situations, especially on the defensive line. Use pass-rush specialists on third-and-long, and PLEASE use Brandon Adams in more short-yardage situations. This also helps to reduce third-down conversions, increase sack and havoc rates, and decrease success rate.
Again, this isn’t an issue of having insufficient talent for Georgia Tech. This is an issue of the talent and personnel available being incorrectly leveraged by the coaching staff. This is on Ted Roof and his staff to fix moving forward.
The offense is much better than it was a month ago, putting the team in great position to win games if the defense is able to do its job in games down the stretch. A few stops will go a long way for Georgia Tech. All they have to do is manage to find ways to get them.