Stats models and rankings

[stinger78]

You really don’t have to be a top 20 offensive team to win big. You just cannot be a bottom 20 defensive team. Get that unit into the top 50 and see what happens. We likely end up with 9 wins last year.

 

[slugboy]

You really don’t have to be a top 20 offensive team to win big. You just cannot be a bottom 20 defensive team. Get that unit into the top 50 and see what happens. We likely end up with 9 wins last year.

There are different scales and ratings out there, but opponent-adjusted, Duke was in the top 30 in a couple of them, and half of our defensive staff is from there.

Depending on what you looked at, our defense ended up in the middle—60’s or 70’s after the bowl. We had so much terrible play at the beginning of the year, but after getting some of the basics down, we got ourselves up to middle of the pack overall, but still low for the P5.

We went through an important section of recruiting and transfer season with most of our defensive coaches knowing they were moving on, or even disengaged from recruiting. Improving our defense will be a challenge, and we need to fit more players in on our front six.

 

[TampaBuzz]

Several ACC schools in there.

How much of their improvement is from playing against the GT defense? I am ducking now!

 

[roadkill]

There are different scales and ratings out there, but opponent-adjusted, Duke was in the top 30 in a couple of them, and half of our defensive staff is from there.

Depending on what you looked at, our defense ended up in the middle—60’s or 70’s after the bowl. We had so much terrible play at the beginning of the year, but after getting some of the basics down, we got ourselves up to middle of the pack overall, but still low for the P5.

We went through an important section of recruiting and transfer season with most of our defensive coaches knowing they were moving on, or even disengaged from recruiting. Improving our defense will be a challenge, and we need to fit more players in on our front six.

Like you said earlier, moving up significantly from a top 30 Offense can be more difficult than getting to top 30 from bottom 30. Frankly, I'd be ok even if our offense stays about the same rankings-wise, if we make significant improvements in the other two phases of the game. Doing that might gain us a couple of extra wins.

It appears that Key has been prioritizing fixing the squeakiest wheels, which is what a good coach should do. In 2022 he didn't have time to do many corrections mid-season, but he did manage to establish at least a functional special teams unit that was no longer a huge liability. That special teams unit was still ranked in the 70s last year, so it is a good candidate for more improvement. Perhaps all it needs to move up 20-30 ranks is a healthy Gavin Stewart. Fingers crossed.

Defensively if we can get to 50th from 75-ish, we should be able to play more "complementary football", and we won't have to win a shootout to beat some of the better offenses.

 

[Root4GT]

Like you said earlier, moving up significantly from a top 30 Offense can be more difficult than getting to top 30 from bottom 30. Frankly, I'd be ok even if our offense stays about the same rankings-wise, if we make significant improvements in the other two phases of the game. Doing that might gain us a couple of extra wins.

It appears that Key has been prioritizing fixing the squeakiest wheels, which is what a good coach should do. In 2022 he didn't have time to do many corrections mid-season, but he did manage to establish at least a functional special teams unit that was no longer a huge liability. That special teams unit was still ranked in the 70s last year, so it is a good candidate for more improvement. Perhaps all it needs to move up 20-30 ranks is a healthy Gavin Stewart. Fingers crossed.

Defensively if we can get to 50th from 75-ish, we should be able to play more "complementary football", and we won't have to win a shootout to beat some of the better offenses.

For the defense getting to 75 would be a big step forward as we were near 100 last season.

 

[roadkill]

For the defense getting to 75 would be a big step forward as we were near 100 last season.

I don't have access to some of the advanced stats, but used ESPN's Defensive Efficiency rank (74th), and Defensive FEI (76th). If 100th is a better representation of where we should rank, then I hope we can move up to 75th. Which ranking had us at 100?

 

[Root4GT]

I don't have access to some of the advanced stats, but used ESPN's Defensive Efficiency rank (74th), and Defensive FEI (76th). If 100th is a better representation of where we should rank, then I hope we can move up to 75th. Which ranking had us at 100?

Scoring defense = 94. Total defense = 120. 1st down defense = 118. 3rd down conversion rate = 105. Rushing defense = 128. Red zone defense = 90.

Apparently per your efficiency numbers you can be below average in efficiency yet still be terrible in giving up points (that actually matters), overall defense, 1st down defense, 3rd down conversion defense and rushing defense.

We gave up way above average points, yards, conversions couldn't stop the run nor stop teams in the Red Zone.

Basically we were a very bad defense. Of course watching the games all of the above was very obvious!

 

[roadkill]

Scoring defense = 94. Total defense = 120. 1st down defense = 118. 3rd down conversion rate = 105. Rushing defense = 128. Red zone defense = 90.

Apparently per your efficiency numbers you can be below average in efficiency yet still be terrible in giving up points (that actually matters), overall defense, 1st down defense, 3rd down conversion defense and rushing defense.

We gave up way above average points, yards, conversions couldn't stop the run nor stop teams in the Red Zone.

Basically we were a very bad defense. Of course watching the games all of the above was very obvious!

I don't want to engage you in another argument over whether basic stats are more meaningful than advanced stats, but I'll ask @slugboy to chime in to see if he can share his thoughts on where our defense should rank. But since this discussion is about objective rankings, I'm ignoring the highlighted part of your post.

 

[Root4GT]

I don't want to engage you in another argument over whether basic stats are more meaningful than advanced stats, but I'll ask @slugboy to chime in to see if he can share his thoughts on where our defense should rank. But since this discussion is about objective rankings, I'm ignoring the highlighted part of your post.

Advanced stats are nice. However if you give up tons of points, bottom 40 in FBS, can’t stop opponents running, can’t get off the field on 3rd down and can’t stop teams in the red zone your defense sucks badly.

The overall stats, for dummies according to you, show our defense was terrible last year.

But if your advanced stats make you believe none of that really matters go for it!

 

[JacketOff]

Advanced stats are nice. However if you give up tons of points, bottom 40 in FBS, can’t stop opponents running, can’t get off the field on 3rd down and can’t stop teams in the red zone your defense sucks badly.

The overall stats, for dummies according to you, show our defense was terrible last year.

But if your advanced stats make you believe none of that really matters go for it!

You’re just playing the semantics game, as has been discussed before. Nobody claims our defense last year was good, or even average. But for some reason you have to insist that they were terrible, instead of maybe just below-average, mediocre, or bad. Not sure why you’re so against the advanced stats either, I guess because it doesn’t fit your terrible narrative. All of them fit within the same category: Unsatisfactory, needs improvement. Anything further is just trying to make people view everything exactly the same as you, or they’re wrong.

 

[Root4GT]

You’re just playing the semantics game, as has been discussed before. Nobody claims our defense last year was good, or even average. But for some reason you have to insist that they were terrible, instead of maybe just below-average, mediocre, or bad. Not sure why you’re so against the advanced stats either, I guess because it doesn’t fit your terrible narrative.

Not semantics when you actually look at points allowed, rushing yards allowed, 3rd down conversions, Red Zone stops. They all are near the Bottom of FBS teams.
We had a very good offense and inspite of the good offense we badly struggled on defense in most games.
Louisville - 39 points
Ole Miss - 48 points
Bowling Green - 38 points
Boston College - 38 points
UNC - 42 points
Clemson - 42 points
That's really bad defense. But go ahead and defend it as just below average. To win you are asking your offense to score near 40 points a game to win 6 of our 12 games. How many of those 6 did we win? One to be clear.

Good defensive games, there were a few:
SCST -13
Wake -16
Miami - 20
UVA - 17
Syracuse - 22 ( of course they didn't have a QB)
So 4 of 12 good defensive games, One decent game against a team without a QB. and UGA - 31 not good and not horrible, Of course if 31 is ok then our defense is bad.

When the defense played solid to good we won 5 games, I give the defense credit for 4 good defensive games and ignore the Syracuse game. If the defense couldn't stop a team without a QB then all bets are off on how bad the team's defense was.

But yea our defense wasn't really that bad last year! LOL

 

[JacketOff]

Not semantics when you actually look at points allowed, rushing yards allowed, 3rd down conversions, Red Zone stops. They all are near the Bottom of FBS teams.
We had a very good offense and inspite of the good offense we badly struggled on defense in most games.
Louisville - 39 points
Ole Miss - 48 points
Bowling Green - 38 points
Boston College - 38 points
UNC - 42 points
Clemson - 42 points
That's really bad defense. But go ahead and defend it as just below average. To win you are asking your offense to score near 40 points a game to win 6 of our 12 games. How many of those 6 did we win? One to be clear.

Good defensive games, there were a few:
SCST -13
Wake -16
Miami - 20
UVA - 17
Syracuse - 22 ( of course they didn't have a QB)
So 4 of 12 good defensive games, One decent game against a team without a QB. and UGA - 31 not good and not horrible, Of course if 31 is ok then our defense is bad.

When the defense played solid to good we won 5 games, I give the defense credit for 4 good defensive games and ignore the Syracuse game. If the defense couldn't stop a team without a QB then all bets are off on how bad the team's defense was.

But yea our defense wasn't really that bad last year! LOL

Here you go in case you missed it the first time:

You’re just playing the semantics game, as has been discussed before. Nobody claims our defense last year was good, or even average. But for some reason you have to insist that they were terrible, instead of maybe just below-average, mediocre, or bad. Not sure why you’re so against the advanced stats either, I guess because it doesn’t fit your terrible narrative. All of them fit within the same category: Unsatisfactory, needs improvement. Anything further is just trying to make people view everything exactly the same as you, or they’re wrong.

Also:

Are you really going to cite fans’ opinions and message boards as evidence? Have you ever read some of the posts on this board from supposedly a “smart” fanbase? Some of the worst takes and opinions in the world exist here.

 

[slugboy]

Advanced stats are nice. However if you give up tons of points, bottom 40 in FBS, can’t stop opponents running, can’t get off the field on 3rd down and can’t stop teams in the red zone your defense sucks badly.

The overall stats, for dummies according to you, show our defense was terrible last year.

But if your advanced stats make you believe none of that really matters go for it!

I know I’ve posted a stat that we’re the #73 ranked in a stat here or #62 in another. I think that’s more precise than is helpful to me.

We had games like BC and Bowling Green where we couldn’t stop them from running and the defense lost us the game. We had games like UVA and Wake where the defense looked like it could win single handedly.

Ole Miss and Clemson —where we had no answers but fought hard—were a little more common for us than games like UNC and Miami.

We came out below average on points allowed, but I don’t think we were the 120th best defense in the country. We were probably one of the bottom 5 P5 teams though.

We had a good secondary and pass defense, which helped us beat UNC and Miami. Run defense was atrocious, which cost us wins against BC and Bowling Green.

There were matchups where we played well and matchups where we didn’t.

In the end, I’d look at the trends, including a respectable game against UGA and holding UCF to 17 to be a reasonable view of how our defense ended up. The team at the end of the season beats Bowling Green and BC—UCF is a really good running team, and we took that away from them. We patched the big hole at the end of the season.

I’d lean toward more of the weighted and normalized measures—below average for FBS and lower end of the P5–than 100th or 120th. We had a rough schedule, and played some of the best offenses in football. I’m glad we didn’t play Oregon or LSU, though.

I’d say 120th in total defense overstates how bad our defense was, and it was a lot of empty yards. Ratings like SP+ that put our defense at 64th are probably as optimistic as you can get. Splitting the difference puts the defense at the top of the weakest 25% of defenses or the bottom of the 25% above that.

Qualitatively, it’s an inconsistent defense that costs you some games that you should have won, and has some occasional good games, but is overall a net negative.

Hopefully, next season is better.

 

[Root4GT]

I know I’ve posted a stat that we’re the #73 ranked in a stat here or #62 in another. I think that’s more precise than is helpful to me.

We had games like BC and Bowling Green where we couldn’t stop them from running and the defense lost us the game. We had games like UVA and Wake where the defense looked like it could win single handedly.

Ole Miss and Clemson —where we had no answers but fought hard—were a little more common for us than games like UNC and Miami.

We came out below average on points allowed, but I don’t think we were the 120th best defense in the country. We were probably one of the bottom 5 P5 teams though.

We had a good secondary and pass defense, which helped us beat UNC and Miami. Run defense was atrocious, which cost us wins against BC and Bowling Green.

There were matchups where we played well and matchups where we didn’t.

In the end, I’d look at the trends, including a respectable game against UGA and holding UCF to 17 to be a reasonable view of how our defense ended up. The team at the end of the season beats Bowling Green and BC—UCF is a really good running team, and we took that away from them. We patched the big hole at the end of the season.

I’d lean toward more of the weighted and normalized measures—below average for FBS and lower end of the P5–than 100th or 120th. We had a rough schedule, and played some of the best offenses in football. I’m glad we didn’t play Oregon or LSU, though.

I’d say 120th in total defense overstates how bad our defense was, and it was a lot of empty yards. Ratings like SP+ that put our defense at 64th are probably as optimistic as you can get. Splitting the difference puts the defense at the top of the weakest 25% of defenses or the bottom of the 25% above that.

Qualitatively, it’s an inconsistent defense that costs you some games that you should have won, and has some occasional good games, but is overall a net negative.

Hopefully, next season is better.

The problem is next year we face a lot of good offenses again. How good no one knows. But when you have to score 39 or more points to win half the games you play your defense is very bad.

Our best defensive games were clearly against bad offensive teams. No surprise there. That’s normal. Wake - 113 in scoring. UVA - 93 in scoring. Cuse - 90 in scoring. Miami was good -38, fortunately their QB was useless by the time we played them.

But Clemson,BC and BG did not have “good” offenses and they ran and passed at Will against us.

Louisville and Ole Miss scored as if we had 8 guys on the field in the second half of both of those games.

We clearly needed a new defensive staff and CBK pretty much cleaned house on the defensive staff. Excellent move.

It will be interesting to see how the defense performs this year. Frankly being FBS average in my view would be a big step forward. Being P4 average would be a remarkable improvement. I just don’t think we have the front 6/7 for that kind of improvement. I sure hope I am wrong.

 

[slugboy]

The problem is next year we face a lot of good offenses again. How good no one knows. But when you have to score 39 or more points to win half the games you play your defense is very bad.

Our best defensive games were clearly against bad offensive teams. No surprise there. That’s normal. Wake - 113 in scoring. UVA - 93 in scoring. Cuse - 90 in scoring. Miami was good -38, fortunately their QB was useless by the time we played them.

But Clemson,BC and BG did not have “good” offenses and they ran and passed at Will against us.

Louisville and Ole Miss scored as if we had 8 guys on the field in the second half of both of those games.

We clearly needed a new defensive staff and CBK pretty much cleaned house on the defensive staff. Excellent move.

It will be interesting to see how the defense performs this year. Frankly being FBS average in my view would be a big step forward. Being P4 average would be a remarkable improvement. I just don’t think we have the front 6/7 for that kind of improvement. I sure hope I am wrong.

Here’s our overall defensive advanced stats

Plays	770
Plays/Game	70 #108
Total EPA	32.80 #80
EPA/Play	0.04 #84
EPA/Game	2.98 #84
Success Rate	44.2% #112
Starting FP	Own 28 #55

Here are the passing stats

Against the Pass
Plays	336
Plays/Game	31 #34
Total EPA	-14.14 #43
EPA/Play	-0.04 #41
EPA/Game	-1.29 #42
Success Rate	43.5% #97

Here are the run stats

Against the Run
Plays	434
Plays/Game	39 #127
Total EPA	46.94 #114
EPA/Play	0.11 #112
EPA/Game	4.27 #118
Success Rate	44.7% #110

Sometimes, teams don’t pass on you because they don’t have to. In our case, our pass defense was passable—i.e, not terrible. Our run defense was terrible. BC and Bowling Green ran against us. In general, teams that beat us ran against us.


Some games, you’re going to have to win 41-38. The average score in CFB is 30 points. 21-17 games are low-scoring affairs, relatively speaking these days.

 

[slugboy]

Here’s our overall defensive advanced stats

Plays	770
Plays/Game	70 #108
Total EPA	32.80 #80
EPA/Play	0.04 #84
EPA/Game	2.98 #84
Success Rate	44.2% #112
Starting FP	Own 28 #55

Here are the passing stats

Against the Pass
Plays	336
Plays/Game	31 #34
Total EPA	-14.14 #43
EPA/Play	-0.04 #41
EPA/Game	-1.29 #42
Success Rate	43.5% #97

Here are the run stats

Against the Run
Plays	434
Plays/Game	39 #127
Total EPA	46.94 #114
EPA/Play	0.11 #112
EPA/Game	4.27 #118
Success Rate	44.7% #110

Sometimes, teams don’t pass on you because they don’t have to. In our case, our pass defense was passable—i.e, not terrible. Our run defense was terrible. BC and Bowling Green ran against us. In general, teams that beat us ran against us.


Some games, you’re going to have to win 41-38. The average score in CFB is 30 points. 21-17 games are low-scoring affairs, relatively speaking these days.

The average score was 30.4 per game by a team. The median is around 27 ppg. Some teams blew the curve. We gave up 30.8 ppg. Yes, the rank is really low, but the difference between #40 and #100 isn’t that much

Overall Statistics​

GT Offense	Value (rank)	GT Defense	Value (rank)
Points/Game	29.7 (#43)	Opp Points/Game	30.8 (#100)
Yards/Game	411.8 (#36)	Opp Yards/Game	449.3 (#123)
Points/Play	0.435 (#36)	Opp Points/Play	0.429 (#91)
Yards/Play	6.0 (#32)	Opp Yards/Play	6.2 (#118)
3D Conversion %	42.04% (#39)	Opp 3D Conv %	42.95% (#103)
4D Conversion %	50.00% (#71)	Opp 4D Conv %	56.00% (#82)
RZ Scoring %	86.36% (#46)	Opp RZ Scoring %	84.91% (#79)

 

[roadkill]

The average score was 30.4 per game by a team. The median is around 27 ppg. Some teams blew the curve. We gave up 30.8 ppg. Yes, the rank is really low, but the difference between #40 and #100 isn’t that much

Overall Statistics​

GT Offense	Value (rank)	GT Defense	Value (rank)
Points/Game	29.7 (#43)	Opp Points/Game	30.8 (#100)
Yards/Game	411.8 (#36)	Opp Yards/Game	449.3 (#123)
Points/Play	0.435 (#36)	Opp Points/Play	0.429 (#91)
Yards/Play	6.0 (#32)	Opp Yards/Play	6.2 (#118)
3D Conversion %	42.04% (#39)	Opp 3D Conv %	42.95% (#103)
4D Conversion %	50.00% (#71)	Opp 4D Conv %	56.00% (#82)
RZ Scoring %	86.36% (#46)	Opp RZ Scoring %	84.91% (#79)

Thanks for the additional data.

A few questions come to mind.

First, if a team has an efficient and explosive offense that is also somewhat turnover-prone, wouldn't that stress their defense by putting it on the field more? Is there a stat that ranks the number of opponent drives?

Also, after the tweet below, this thread took off in the direction of discussing how much improvement we could expect again this year from our offense, and then our defense. The tweet stated that last year's offense improved to 27th - what stat do you think they used, and does it have validity? What is a corresponding stat for our defense?

 

[slugboy]

Thanks for the additional data.

A few questions come to mind.

First, if a team has an efficient and explosive offense that is also somewhat turnover-prone, wouldn't that stress their defense by putting it on the field more? Is there a stat that ranks the number of opponent drives?

Also, after the tweet below, this thread took off in the direction of discussing how much improvement we could expect again this year from our offense, and then our defense. The tweet stated that last year's offense improved to 27th - what stat do you think they used, and does it have validity? What is a corresponding stat for our defense?

I’ll answer the second question first—they used yards per play. The defensive stat is yards per play against. This year we were #118 in yards per play against at 6.2 yards/play. The year before we were at 5.4 (#63). Not only were we atrocious last year, but we plummeted from the year before.
(Three players graduating—two linebackers and one EDGE—were probably responsible for a lot of that)

Yards per play and points per play probably tell you a lot about our offense and defense, except for one thing—it’s not adjusted for strength of schedule. Ole Miss, for example, was one of the top 10 offenses, or just outside of that. If one team is playing teams like Ole Miss and Louisville while another one is playing UMass, it’s not a fair comparison.

Still, it’s not good.

=======

For being turnover-prone, I’d just go to EPA. There are others, but that one is easy and available. Turnovers end up being negative expected points added. A pick-six can be anywhere from -4 points to -14, depending on where on the field it happens (if it happens in the red zone at the 1 yard line, it’s about -14 points, if it happens from your 1 yard line, it’s about -4 points).

Expected Points Added: A Full Explanation

Expected Points Added (EPA) is a commonly used advanced statistic in football. In short, this stat measures how well a team performs compared to their expectation on a play-by-play basis. EPA and E…

bestballstats.com

There’s a stat called “Bad Play Rate”, but I don’t see a place to find that. Ridder and the Falcons would have been awful on that stat. In fact, Ridder was #24 out of 32 QBs with an individual EPA of 28, while Sam Howell—who people thought played awful this year—was #19 at 49.7. Dak Prescott was #1 and Mahomes was #3.

 

[57jacket]

LOL. We have some argumentative people on this board. Give it up guys. Everyone has a point. Ha Ha

 

[Root4GT]

GT's 2023 defense finished last in the conference in yards allowed per game (438.2), rushing yards allowed per game (225.7), second-to-last in points per game allowed (30.5).

That says a lot. Anyone who watched our games could see how bad the defense was last season.

Hopefully the new staff can get the defense to at least ACC average in points allowed and yards allowed as well as 3rd down stops. Big task but essential if we are going to have a 7+ win season.