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Advanced Stats Review: GT vs. BC

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A battle of the ACC’s middle class sent GT back towards the bottom

NCAA Football: Georgia Tech at Boston College Paul Rutherford-USA TODAY Sports

Final Score: Boston College 48-27

Projected EPA Margin of Victory: BC by 30.12

*This and all other stats below do not include garbage time plays between BC’s score to go up by 27 in the 4th and GT’s final score to cut it to 21

GT Win Probability (Based on Success Rate, Yards Per Play, and EPA): 7%

If last Saturday reminded Georgia Tech fans just how far away we are from the elite of college football, this Saturday demonstrated that we are not even yet ready to take our place in the ACC’s middle class. The team that had run for 66 yards per game entering this week put up 266 yards on the ground to go with a 55% success rate on called pass plays (includes sacks and scrambles). To make matters worse, Tech once again turned the ball over three times, including a fumble by Jordan Mason that was returned for a touchdown. Georgia Tech nearly matched Boston College in baseline efficiency metrics, but the game was once again lost by Tech on turnovers and chunk plays, this time on the ground.

Success Rate Comparisons and Individual Player Stats

GT BC Success Rates

Success Rate O GT Offense D BC Offense National Avg
Success Rate O GT Offense D BC Offense National Avg
Down 1 56.00% 1 38.70%
2 38.90% 2 59.10%
3 20.00% 3 44.40%
4 33.30% 4
Qtr 1 38.50% 1 58.80%
2 46.20% 2 37.50%
3 52.60% 3 42.90%
4 27.30% 4 57.10%
Pass P 30.30% P 54.50% 41%
Rush R 60.90% R 41.00% 42%
Overall 42.90% 46.80% 42%
Success rate is the baseline metric for efficiency. As a reminder, a successful play gains 50% of the needed yards on 1st down, 70% on second down, and 100% on third or fourth down.

The defense gave up an average rushing success rate against a team that came in utterly incapable of running the ball and the worst passing success rate of the season outside of the Clemson game. BC is a a slightly above average offense that GT made look elite at times during this game. It was a sloppy, undisciplined performance from a defense that frequently missed tackles and found itself badly out of position on pass plays.

Georgia Tech had its worst offensive passing success rate performance of the year, again not counting the Clemson game. In fact, GT was twice as effective on called running plays in terms of success rate. Boston College burst out of the gate with a 20% success rate advantage in the first quarter, but I wonder if the game flow might have developed differently if Georgia Tech had stuck with the running game more in the first half.

GT Rushing Success Rates

Running Backs Carries Rushing Success Rate Highlight Yards
Running Backs Carries Rushing Success Rate Highlight Yards
10 8 0.75 27.5
21 6 0.25 -4
27 6 0.67 5.5
28 1 0 1
4 2 0.5 2.5

On called running plays, Jeff Sims was nearly perfect. This was an advantage GT knew it had going into the game, but it was not utilized enough. Jahmyr Gibbs had his worst performance of the season, and Jordan Mason didn’t get significant carries until it was too late.

GT vs. BC Receiving Stats

Receivers Receiving Success Rate Avg Target Air Yards Targets % of Team Air Yards YACatch RACR WOPR
Receivers Receiving Success Rate Avg Target Air Yards Targets % of Team Air Yards YACatch RACR WOPR
1 0 8 6 14.72% 12 0.52 0.26
2 0.8 17.6 5 26.99% -4 0.88 0.65
11 0.5 7.5 2 4.60% 5 0.93 0.12
12 0.25 19.5 4 23.93% 4 0.27 0.3
15 0.25 5.5 4 6.75% 1 0.23 0.08
18 1 30 1 9.20% 1 1.03 0.25
21 0.25 0 4 -1.23% 41 11.25 0.22
27 1 9 1 2.76% 28 6.89 0.25
26 0 35 1 10.74% 0 0 0.08
80 0 2.5 2 1.53% 1 2 0.04
*RACR compares a receiver’s total receiving yardage to the air yards on targets to them, and anything above 1 is good. WOPR tells us how heavily the receiver is being leaned on in the passing game by combining the proportion of targets with the proportion of air yards.

The most reliable targets in the GT passing game this year, Camp, Carter, and Gibbs, all had subpar performances against BC. Ahmarean Brown finally had a breakout game, but it was not enough as no other receiver with more than 2 targets had a 50% success rate or higher.

Let’s turn now to the full advanced box score to see where GT came up short.

Advanced Stats Comparison

GT vs BC Advanced Box Score

Adv Box Score GT Opponent National Avg
Adv Box Score GT Opponent National Avg
Snap Count 56 63 71.5
# Pass Attempts 33 22 31
Avg Starting FP 79.8 64.55 70.5
YPP 4.94 5.72 5.7
YPA (incl. sacks, scrambles) 6.09 8.18 7.39
% of Passes on 1st Down 52% 19% 40.17%
Avg EPA/play -0.23 0.28 -0.01
Avg EPA/pass -0.13 0.56 0
Total EPA -12.62 17.5 -0.96
Avg Air Yards / Completion 10.47 6.17 6.14
Air Yards / Attempt 11.21 7.53 8.89
CP 53.57% 63.16% 62.54%
CPOE -3.97% 1.18% 0.00%
Total Line Yards 99 164.5 2.55
Opportunity Rate 66.67% 53.85% 42.42%
Power Success Rate 100.00% 50.00% 68.60%
Stuff Rate (Offense) 21.74% 12.82% 19.17%
Havoc Rate 8% 13% 21.00%
Pressure Rate 23% 15% 30.70%

As mentioned above, this box score only includes non garbage time plays. So, where was the game lost for Georgia Tech on Saturday afternoon?

  • Yards per pass attempt: Including sacks and scrambles, Boston College outgunned GT by an average of 2 yards per called passing plays. Phil Jurkovec’s scrambles consistently took advantage of massive Georgia Tech defensive lapses. The back seven struggled mightily to pass off receivers to one another and to maintain spatial awareness, setting up some huge gaps for Jurkovec to find.
  • Run Defense: Boston College ran a completely different game plan that expected, as they called run plays on 81% of first down plays and had twice as many called run plays compared to pass plays in non garbage time. Georgia Tech was only able to stuff 12% of those runs (zero or negative yards), while BC had an opportunity rate (4 or more yards) of 54%, well above the national average.
  • Turnovers: As we will see below in the EPA impact breakdown, Georgia Tech’s three turnovers were once again costly to the point of turning a close game into a blowout.
  • Field Position: Because of poor decisions on kickoffs and punts as well as the turnover deficit, Georgia Tech suffered a 15 yard deficit in average field position

EPA Highlights

EPA calculates the expected number of points added (or lost in the case of a negative number) on a particular play based on the down and the location on they field. Akshay Easwaran did a great job priming us for EPA this summer. Check out his column here for background.

The EPA totals for this game leave us with a 30 point projected deficit for GT during the non garbage time portions of the game. Against a team that was very evenly matched with the Yellow Jackets, this is a massively disappointing performance. Let’s look at some of the plays that tipped the outcome in the Eagles’ favor.

Most Helpful Plays

  1. Jeff Sims’s 37 yard pass to Jordan Mason on 3rd and 5 to advance to the BC 35 in the middle of the second quarter. 3.85 EPA
  2. Jeff Sims’s 31 yard touchdown pass to Peje Harris on 2nd and 6 to make it 31-14 in the second quarter. 3.35 EPA.
  3. Jeff Sims’s 32 yard touchdown pass to Ahmarean Brown on 1st and 10 to make it 24-7. Both of these throws from Sims were excellent and probably the most encouraging development of the game. 3.00 EPA.

For the second week in a row, there were no other plays that deserved to be #4 or #5. GT’s only other significant EPA gains came in garbage time. The passing game was explosive in the first half, with three second quarter throws making up all of the EPA highlights in this game for Tech.

Most Hurtful Plays

  1. Jordan Mason’s fumble, returned for a BC touchdown in the 2nd quarter. -7.68 EPA.
  2. Jeff Sims’s fumbled snap, recovered by BC on the GT 22 to set up BC’s second touchdown. -4.55 EPA.
  3. Jeff Sims’s interception on his final play of the day on 1st and 10 from the GT 3, intercepted at the GT 12. -3.90 EPA.
  4. Zay Flowers’s 22 yard run for a touchdown on a 3rd and 4 for BC to go up 31-7. -3.60 EPA.
  5. Pressley Harvin III’s incomplete pass to Josh Blancato on a failed fake punt to end GT’s opening drive of the game from the BC 29. -3.42 EPA.

It fits the feel of this game that GT’s five worst EPA plays are three turnovers, one rushing touchdown allowed, and one special teams travesty.

Tracking Season Goals

*I set these goals for the 2020 season in some of my offseason preview work. We will be tracking them as we go this year.

GT vs BC Season Goals

Metric Season Goal This Week Season Long
Metric Season Goal This Week Season Long
Offensive Passing Success Rate >40% 30% 43%
Offensive Power Success Rate >70% 100 75%
Defensive Power Success Rate <70% 50% 83%
Defensive Stuff Rate >20% 13 18%
Defensive Havoc Rate >21% 8% 15%

Once again, it was a disappointing performance in comparison to our preseason goals. As mentioned above, the offense had its worst passing success of the season outside of the Clemson game. We did well on power success rate on both sides of the ball, but there were very few of these opportunities because of the nature of the game flow. Our stuff and havoc rates on defense were devastatingly low, pointing to an inability to get BC behind the chains and get off the field.

Takeaways

  1. Considering the quality of the opposing offense, this was the worst defensive performance of the year. Significant personnel changes should be considered for the final five games, starting at the linebacker position. In his postgame interview, one of the starting linebackers said BC consistently ran three plays the defense was not ready for: slip screens, quarterback keeps on zone reads, and counters. That is bad coaching, and those are all plays that heavily target the linebackers.
  2. The missed assignments in the secondary, which was supposed to be the leading defensive unit, are baffling, especially considering our head coach prides himself on putting defensive backs in the NFL.
  3. The Georgia Tech coaching staff made two awful calls on special teams. A fake punt from the BC 29 failed and cost us 3.4 EPA, while an obvious onside kick was not recovered in the second quarter and cost us 2.4 EPA. These two decisions effectively cost us 6 points. I know this coaching staff prides itself on special teams and surprise plays, but these were neither surprising nor effective.
  4. Jeff Sims is an enigma. He had several perfect throws on balls down the field, he had a 75% success rate on called rushing plays, and he had 2 game changing turnovers once again.

This game left a very bad taste in my mouth, as well as a whole host of other GT fans. In a game that we went into with about a 45% win probability, to come out with a 7% postgame win expectancy feels like an abject failure. Because it was. The offense made the same turnover and penalty mistakes that have plagued us this season. The defense blew coverages and missed tackles in a way that looked like they either aren’t being coached or aren’t paying attention to the coaching. Two catastrophic special teams calls (not to mention another missed XP) put the icing on the cake. A game that looked to be evenly matched turned into a blowout, and a much better opponent awaits next Saturday on the Flats.