2021 stats year in review

slugboy

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The first block of stats is going to come from https://collegefootballdata.com/team/Georgia Tech. The glossary is available at https://collegefootballdata.com/glossary if you wonder where points per opportunity and other terms come from. Scoring Opportunities consist of all offensive drives in which the ball has been advanced past the defense's 40 yard line.

Scoring OpportunitiesOffenseDefense
Opportunities5970
Points Per Opportunity3.24.2

3.2 points per opportunity is middle of the pack for offense. 4.2 points per opportunity is a wreck for the defense--if the other team got the ball to our 40, they were usually scoring TDs.

OK, let's look at "Havoc". Havoc refers to the percentage of plays in with the defense recorded a TFL, forced a fumble, intercepted a pass or broke up a pass. DB Havoc is the percentage of plays in which the defense defended or intercepted a pass.

Georgia TechOffenseDefense
Total20%15%
Front Seven14%11%
DB6%4%

We've had requests for "offensive line" stats. The "Offense" column of Havoc is largely a line sack, especially the 14% from the front 7 on defense. Those are players coming through the lines and getting sacks, disrupting passes, tipping passes, and getting tackles for loss.

You may ask yourself, "Why is Slugboy highlighting that 14%". Is that a big number? As it turns out, it's the worst in the conference. The horizontal axis is the Front 7 Havoc on offense (how often the other team's defense caused havoc) and the vertical axis in the chart below is the defense's front 7 havoc.

The ACC has a cluster of good offensive lines (WF, Pitt, Louisville, Clemson, NCST), and a cluster of bad ones (GT, Syracuse, Miami, VT, FSU, Duke, BC, and UNC), and UVA kinda all alone in average space. Also, UVA's defensive front 7 didn't disrupt much of anything. We let our opponents wreak more havoc than any other team in the conference.
1640982262945.png


For those of you who want to see all defense, here is defensive front 7 havoc (horizontal) vs defensive DB havoc (vertical). Our DBs broke up fewer passes and made fewer interceptions than any other team in the ACC. Front 7 is OK.
Defensive Havoc (Good)

1640982693668.png


On the offensive side, here's the same (look at the chart below). Horizontal is front 7 havoc and vertical is DB havoc. You want to be in the bottom left of this chart (don't have many passes defended or intercepted, and very few sacks). Wake, UVA, and Miami have a lot of passes defended and other DB havoc stats. They also slung the ball a lot more times than we did.

What does this chart mean?
We've had a lot of arguments that we threw too many picks, and that our offensive woes were mainly at the QB position. We actually come out in the middle here. The problem is too many sacks, too many tackles for loss, and too much disruption from the other team's front 7.
Yeah, we threw picks. Picks are bad. There were bad reads and bad decisions and bad progression. But that's not what sank us--what sank us was the front 7 of the other team getting in our backfield and making hay.
Offensive Havoc (Bad)
1640982845238.png
 

slugboy

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Here are some of our rushing stats:

OffenseDefense
Power Success78%65%
Stuff Rate16%14%
Line Yards per Rush3.13.3
Second Level Yards per Rush1.21.1
Open Field Yards per Rush21.3

If we got into the open field, we made hay. That highlighted "2" is a really good number, and it wants to say that our running backs were really good. How does this compare to the conference?

Line Yards (x) vs Open Field Yards (y)

1640983646336.png

For running, we're behind (to the left of) Duke and Syracuse and VT and Pitt, etc. I'm really kind of stunned to see Miami orphaned alone in the lower left (no wonder Manny got fired). We could run for some yards when we got free, and we're up high on the chart in that regard but being behind Duke and Clemson and VT in our ability to push for some yards isn't great.
I'm surprised to see us even fare this well on the x-axis, but I saw a lot of our RBs hit in the backfield and make it to the line of scrimmage or better. I don't have the stats to show it, but my eye test has this as a place where the RBs carried the team and brought the score up.
 

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slugboy

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How'd we do in scoring (offense and defense)?

Here's Expected (Predicted) Points added. Expected Points Added (EPA) uses Expected Points to measure the outcome of a play. It takes the EP value from the beginning of a play (e.g. 2nd and 5 at the 50) and subtracts it from the EP value resulting from the play (e.g. rush for 10 yards results in 1st and 10 from the 40). Passing Downs are defined as 2nd downs with 7 or more yards to go or 3rd and 4th downs with 5 or more yards to go. Rushing downs are the downs that aren't passing downs ;)

OffenseDefense
All0.1290.304
Rushing0.1020.112
Passing0.1740.563

We gave up a ton of points. Let's compare to success rate.
Success Rate is an efficiency metric that determines the success of a play. Successful plays meet one of the following criteria:
  • the offense scored
  • 1st downs which gain at least 50% of the yards to go
  • 2nd downs which gain at least 70% of the yards to go
  • 3rd and 4th downs which gain at least 100% of the yards to go

OffenseDefense
All40%47%
Standard Downs47%51%
Passing Downs24%37%

I guess we had a "break but don't bend" philosophy on passing downs. We either stopped you or we got burned bigtime. From another chart (not shown here), our run defense looks better because our passing defense was so weak.

Also, if we got behind the chains, we were shafted. The 24% on offensive passing downs translates to "our offense was not built for 3rd or 4th and long".

How did our offense stack up compared to the rest of the conference?

Success Rate (x) vs Expected Points (y) Offense
1640984647221.png

Yeeeesh. We weren't efficient at keeping ahead of the chains (horizontal axis) or scoring (vertical axis). Congrats UVA--you really rocked on offense.

Same on defense
Success Rate (x) vs Expected Points (y) Defense
1640984917418.png

OK, you REALLY REALLY don't want to be in the upper right. Duke, UVA, and GT REALLY REALLY couldn't get off the field or stop their opponents from scoring. Keeping the opponents from getting first downs was probably a slightly bigger deal than giving up points, but they go hand in glove. Congrats to NCST and Clemson for having great defenses. Pitt looking good there, too.
 

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slugboy

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Here is STUFF RATE (x-axis) vs POWER SUCCESS (y-axis)
Stuff Rate is the percentage of running plays stopped at or behind the line of scrimmage.
Power Success measures the percentage of running plays on 3rd or 4th down from 2 yards or less in which an offense either converted into a 1st down or scored a TD. 1st and 2nd down and goal plays within the 2 yard line are also included.

Upper left is the place you want to be. That's 1. not getting caught behind the line of scrimmage + 2. making the hard yards when you need to. GT's position on this chart doesn't mesh well with my memories of getting stuffed on 3rd and 2.

Statistically, the upper left is usually a pat on the back for the offensive line.
1640985204129.png
 

slugboy

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Because I gave the Offensive Stuff Rate (x-axis) vs Power Success (y-axis), here's the DEFENSIVE version.

1640988831111.png

The farther to the right you are, the more you're getting behind the line of scrimmage. Well done, NCST. The further down you are in the chart, the more you're getting off the field on 3rd and 4th down (and short). Well done, NCST, again.

So, we bowed up really well on 3rd or 4th and short. But, we really weren't getting tackles for loss and sacks. We're on a strange part of the graph, being good in short yardage, but not so good at getting behind the line of scrimmage. Miami is the opposite--they make disruptive plays but give it up on 4th and 1.

Tip of the cap to Pitt, too. Good defense.

UVA and UNC and Syracuse and Duke fit into that "run on us--we won't stop you" class of defense.
 

awbuzz

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None of the charts "surprised" me, except for the stuff rate for the offense. We couldn't seem to get it into the EZ all that well from "... and goal" downs. But maybe my memory is jaded.
 

takethepoints

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Fine effort. The scatterplots are much more useful, imho, then the summary stats. One quibble = you don't label the axises on the graphs; translating the main labels to the axises shouldn't be my problem. I also would have liked to see some 2020 v. 2021 graphs. That would have made it easier to see where - if anywhere - we had improved versus our competitors.

And, yes, there's nothing too surprising here.
 
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