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+---- Thread: *Exploring the Impact of Sacks (/showthread.php?tid=46941)
*Exploring the Impact of Sacks - caleb.grim - 08-07-2023
Hello everyone! As a new user, I am not sure if any type of analysis like this has been done. I was hoping to get this done before S43 started but I was just a little bit late. Hopefully, you still find this interesting!
Exploring the Impact of a Sack
Since I created an offensive lineman, I have been curious of ways to look at the value they bring to a team. One of their few statistics is "sacks allowed" and that piqued my interest into how sacks impact a game. This lead to me looking through the play by play for every S42 ISFL game during the regular season and the playoffs and tracking the results of each drive.
I categorized the drives using the following:
Defensive Touchdown
Turnover on Downs
End of Half/Game
Field Goal
Missed Field Goal
Punt
Safety
Touchdown
Turnover (that didn't result in a touchdown)
For each type of drive I assigned a point value based on how many points were scored by the team in possession as follows:
Defensive Touchdown: -7 points
Safety: -2 points
Field Goal: 3 points
Touchdown: 7 points
All other outcomes: 0 points
Using this weighting, I created a metric called "Expected Points Per Drive".
Baseline
In order to make a good comparison in how much a sack affects a drive, I first looked at all drives of season 42 to find the Expected Points per drive.
By my count, there were a total of 2995 drives. During these drives, 632 touchdowns were scored, 382 field goals were made, 14 safeties were scored by the defense, and 40 touchdowns were scored by the defense. The chart below has the full breakdown of all drives.
![[Image: All-Drives-Summary.png]](https://i.ibb.co/Gnn2YJn/All-Drives-Summary.png)
Using this data, I was able to calculate the "Expected Points Per Drive" or EPPD. The calculation was the following:
(632*7 + 382*3 - 40*7 - 14*2) / 2995 = 1.757 Points Per Drive.
Sacks
Taking all of this information, I then highlighted all drives that included a sack in some way. I did not differentiate between multiple sacks, which down the sack occurred, or starting field position. The only criteria was at least one sack.
By my count, there were a total of 728 drives that included at least one sack. During these drives, 53 touchdowns were scored, 87 field goals were made, 6 touchdowns were scored by the defense, and 13 safeties were scored by the defense. The chart below has the full breakdown of all drives that included at least one sack.
![[Image: Drive-Summary-with-Sack.png]](https://i.ibb.co/rGYDBDr/Drive-Summary-with-Sack.png)
Using this data, the EPPD when a sack occurred during the drive dropped to 0.775 points per drive.
What does allowing a sack do? It cuts the probability of a touchdown from 21% to 7% and increased the probability of a punt from 39% to 55%. The other results stayed roughly the same, though it is worth pointing out that all but one safety occurred on a sack drive (usually the sack itself).
Clean Drives (No Sacks)
What about when the offense avoids giving up a sack? This would be all the drives except the drives highlighted by a sack. Of these drives 579 resulted in a touchdown, 295 resulted in a field goal, 1 resulted in a safety, and 34 resulted in defensive touchdowns. The chart below breaks down all drives that did not include a sack.
![[Image: Drive-Summary-No-Sack.png]](https://i.ibb.co/kKxWcsc/Drive-Summary-No-Sack.png)
This resulted in an EPPD of 2.072 points per drive. Again, the big movers here are touchdown percentage changing from 21% to 25% and punt percentage from 56% to 34%.
Conclusion
It comes as no surprise that sacks are a bad thing for an offense and a good thing for a defense. However, with this data, I hope that we can begin to quantify this idea a little better. One could make the claim with this data that the first sack of a drive is worth 1.297 points. In whatever way possible, whether it be through personal or game plan, I would think that a team that is able to prioritize getting to the quarterback will see increased success.
As a side note, I did keep track of "sack differential" (similar to turnover differential). During season 42, teams with a positive sack differential had a record of 57-28 for a winning percentage of .671. Based only on this data (unrealistic but fun), a team with a positive sack differential would win 10 or 11 games, which should be more than enough to make the playoffs. Once there, anything can happen!
RE: Exploring the Impact of Sacks - ForSucksFake - 08-07-2023
So, sacks are good?
RE: Exploring the Impact of Sacks - negs - 08-07-2023
Great read!!!
RE: Exploring the Impact of Sacks - aeonsjenni - 08-07-2023
i love this analysis! was there any technical issue in counting the number of sacks during a drive or did you just want that not to be the focus of the research? i guess once you get past like 2 sacks the sample size becomes way too small to be meaningful
RE: *Exploring the Impact of Sacks - lemonoppy - 08-07-2023
Dope read! I love any and all of the stats stuff from this league.
How did you pull sack data on drives? That's really cool
RE: *Exploring the Impact of Sacks - Swanty - 08-08-2023
This is awesome! Really interesting, especially for us OLs!
RE: Exploring the Impact of Sacks - caleb.grim - 08-08-2023
(08-07-2023, 10:37 PM)aeonsjenni Wrote: i love this analysis! was there any technical issue in counting the number of sacks during a drive or did you just want that not to be the focus of the research? i guess once you get past like 2 sacks the sample size becomes way too small to be meaningful
I did keep track of when multiple sacks occurred but you are correct that the sample size was very small. I really just made that decision for simplicity.
RE: *Exploring the Impact of Sacks - caleb.grim - 08-08-2023
(08-07-2023, 10:59 PM)lemonoppy Wrote: Dope read! I love any and all of the stats stuff from this league.
How did you pull sack data on drives? That's really cool
I had to go through the play-by-play data. Luckily, sacks are highlighted there so that sped up the data collection.
RE: *Exploring the Impact of Sacks - CptGoosar - 08-08-2023
That’s a great read. Love it. Great work