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Defensive turnover rates in the ACC, or, where are NC State's daggone takeaways?

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Out of some morbid curiousity, perhaps, I've been digging into NC State's production on the defensive side--specifically, the Wolfpack's production when it comes to being disruptive and/or forcing turnovers. Now, by most raw statistics, State looks dreadful--tied for 119th in turnovers forced (5), tied for 105th in interceptions (3), tied for 109th in fumbles recovered (2).

But this is not a complete picture by any means, especially since some adjustments are necessary. Teams have played different amounts of games, and they've played vastly differing numbers of snaps. No FBS defense has played fewer snaps than NC State's. There are defenses that have been on the field for 200+ more plays than NC State's defense.

Lack of opportunity may partially explain why NC State has a paltry turnover total, but as you'll see shortly, that total is bad even when accounting for opportunity. Last offseason, Dave Doeren said he wants a defense that averages a takeaway every 30 plays, which, as it turned out, is a difficult (though not impossible) mark for anybody to hit.

My research from the 2013 season found the FBS average was a takeaway for every 41 plays. With that in mind, let's see how the ACC is doing in this and other categories so far this season. (Rank within ACC in parentheses.)

ACC Defenses - 2015 Plays/Turnover Forced Opp. PassAtt/INT Opp. PassAtt/Defensed Opp. Rushes/FF Opp. Plays/TFL
Miami 25.9 (1) 16.6 (1) 6.1 (2) 68.3 (13) 11.8 (11)
Louisville 34.2 (2) 20.3 (2) 7.6 (6) 113.5 (14) 11.7 (10)
VT 34.2 (3) 24.4 (4) 5.3 (1) 30.4 (2) 9.5 (7)
Syracuse 34.7 (4) 31.8 (8) 10.6 (12) 28.2 (1) 9.0 (6)
Clemson 34.8 (5) 21.9 (3) 6.4 (3) 38.3 (7) 6.8 (2)
GT 34.8 (6) 33.0 (10) 11.0 (13) 36.4 (6) 14.6 (13)
Duke 44.1 (7) 28.6 (6) 6.8 (4) 36.3 (5) 8.8 (5)
Pitt 44.8 (8) 28.5 (5) 7.4 (5) 31.2 (4) 7.6 (3)
BC 44.9 (9) 32.2 (9) 8.8 (9) 42.2 (9) 6.6 (1)
FSU 50.6 (10) 52.0 (T11) 8.0 (8) 39.4 (8) 12.7 (12)
UNC 54.0 (11) 29.6 (7) 5.9 47.3 (10) 16.6 (14)
NCSU 66.4 (12) 52.0 (T11) 9.2 (11) 58.7 (12) 8.7 (4)
Wake 71.0 (13) 52.0 (T11) 7.8 (7) 54.0 (11) 11.2 (9)
UVA 101.0 (14) haha UVA has no INTs 14.5 (14) 30.9 (3) 9.9 (8)

Hopefully those labels all make sense, but for example: Miami's defense averages one takeaway for every 25.9 snaps, an INT for every 16.6 opponent pass attempts, a pass defensed (PBU or INT) every 6.1 opponent pass attempts, a forced fumble every 68.3 opponent rush attempts, and a tackle for loss every 11.8 plays.

There's a good amount of noise in the numbers, with no schedule adjustments (plus whatever turnovers that have occurred on special teams are lumped in here), but this at least gives us a sense of how NC State is doing within the league. And for the most part it is not doing well.

State's average of one takeaway every 66.4 snaps would have ranked 118th in 2013, and the next three columns are correspondingly poor. The odd thing is the final column, where State rates well. You would think that a team doing relatively well in terms of TFL rate would see better results in the turnover column. Tackles for loss work as a rough measure of pressure at the point of attack, and the more pressure you create, the more mistakes your opponent will make. Or so it goes in theory.

One other thing we can look at is Havoc Rate, which is a real simple measure of disruption that was cooked up by SB Nation's Bill Connelly. Add up TFLs, forced fumbles, and passes defensed (again, pass breakups and INTs) and then divide that number by total plays.

NC State's defense again fares well relative to its ACC brethren, though it is not exceptional by national standards. (It ranked 45th in this metric coming into the weekend.)

ACC Defenses - 2015 Havoc Rate
Clemson 22.5%
BC 21.8
Pitt 21.2
VT 19.8
Duke 18.4
NCSU 17.5
Syracuse 17.3
Miami 17
FSU 15.6
UVA 15.1
Louisville 14.9
Wake 14.8
UNC 13.2
GT 12.4

Havoc Rates above 20% are elite--Clemson was tops nationally heading into this weekend, though the Tigers' rate has dipped a smidge since. And NC State's rate is above FBS average. Maybe this is a sign that the Wolfpack is due some course correction when it comes to forcing turnovers. Or perhaps the football gods ain't having it this year.

State's Havoc Rate implies at least slightly better numbers in a few of the categories in the first table. You'd think a team with an above average rate of disruptive plays would snag a turnover at a better rate than one every 66 plays. And like I said, the latter rate is really, really poor, so it would be difficult for it to decline over the latter half of the season.

I'm optimistic that we'll see some variety of turnaround, but the degree is impossible to estimate. There is so much random flukitude in turnovers, it's anybody's guess. (I mean, look at how badly Georgia Tech rates in the disruption categories, yet the Jackets are 2nd in the ACC with 13 takeaways.)

The defense's turnover rate should get better, but if by some cosmic improbability it doesn't, then NC State had best hope its offense remains stingy in the ball security department--the Wolfpack has only four turnovers this season. (One every 108 snaps.)