The Liar Stat

Stephen Dunn

Why I hate what the sack has done to stats in college football and why you should too.

Comrade KJ has previously talked on this issue at a game by game level, this is just going further

On October 26th, Connor Cook headed into the locker room of Memorial Stadium with what would generously be called a bipolar stat-line. On 11 passing attempts, he'd managed 10 completions for 111 yards and a ridiculous 91% completion percentage. He also, on a healthy 7 rushing attempts (more attempts in that half than any full game of his other than USF), had managed a laughable -2 yards (what's known in college football circles as 'a Toussaint'). It was in many ways a near perfect dichotomy of a great passing and awful rushing performance that would lead anyone glancing at the halftime score-sheet to make some pretty solid assumptions about what kind of QB Michigan State was rolling out there and also to wonder quite why he was almost averaging a carry for each passing attempt.

The thing is, of course, that that stat-line was a lie, as indeed all college quarterback stat-lines have progressively become more and more of an irritating lie, and it's all thanks to the sack, or more accurately, how the NCAA has decided to score-keep the sack.

See, before he threw a 29 yard jump-ball to the defensive back covering Bennie Fowler that was improbably reeled in for a TD (itself a bit of a statistical fib that is much harder to correct for, and is definitely a subject for a separate post), Cook was felled by a pair of ugly sacks on first and second down for a total loss of 15 yards. These were two downs where MSU was clearly trying to throw the ball, and the scorekeeper correctly credited each as a sack, and yet when it came time to file '1 attempt, -6 yards' and '1 attempt, -9 yards' into the box-score they went, as they always do, into Cook's (and the team's) rushing column instead of his passing column.

To ask 'Why do they do it that way?' is almost unnecessary, because the answer is likely 'for no good reason'. To ask 'Well, what's the big deal?' is to uncover a multitude of annoyingly minor and annoyingly major bugs with how we view both quarterbacks and modern offenses, bugs that could be fixed with relative ease.

In short, a sack should not be considered a rush attempt. Furthermore, a sack should be, for the purposes of a boxscore, considered a pass attempt that is a. an incompletion and b. for negative yardage.

What does this relatively minor change do?  My friends, it shows us a nearer vision to the truth.

Connor Cook, 1st half vs Illinois

Passing

Rushing

Sack Adjusted?

completions

attempts

yards

YPA

carries

yards

YPC

No

10

11

111

10.09

7

-2

-0.29

Yes

10

13

96

7.38

5

13

2.60


On the individual level, it shows us a QB who was having a very good day through the air, but not like, an insane day, and who was chipping in some not insignificant yardage on the ground on a handful of carries (about a first down and a half's worth). It looks more accurate, it looks more like the QB you're used to seeing when you think back on Connor Cook's year, because it is more accurate.
It also had a significant effect on the overall stats of MSU's rushing attack.

MSU offense, 1st half vs Illinois


Passing

Rushing

Sack Adjusted?

completions

attempts

yards

YPA

carries

yards

YPC

No

10

11

111

10.09

21

53

2.52

Yes

10

13

96

7.38

19

68

3.58


Forget for a second about the big difference between ~2.5 and ~3.6 YPC or the huge difference between ~10.1 and ~7.4 YPA on an efficiency level, and take a second to look at the comparative cost/benefit of running the ball vs passing it. Before adjusting these numbers, you'd guess the average pass play was gaining 4 times the yardage of the average run play, after adjusting, that falls to only 2 times as much. Remember, this is all from just 2 sacks!
And while this is a particularly vibrant example on a couple of levels, even more mundane games where the QB perhaps takes a single sack for -4 yards add up over the course of the season and severely distort the end of year numbers.

Sack adjusting the Michigan State Quarterback

Brian Hoyer, average starting season

Passing

Rushing

Sack adjusted?

Completions

Attempts

Comp %

Yards

YPA

TD

INT

Carries

Yards

YPC

TD

No

202

365

55.28%

2565

7.04

15

10

45

-100

-2.21

1

Yes

202

387

52.13%

2417

6.25

15

10

23

49

2.11

1


I think it's probably for the best that Hoyer started at MSU when he did, graduated when he did, and that his first season as a starter was significantly better than his second, because his college stats as a whole have always kind of signaled 'Andrew Maxwell+' to me. Given that, it's pretty amazing that he almost grabbed hold of a steady starting QB job in the NFL this year and was equally unfortunate that he had to get injured how and when when he did.

Kirk Cousins, average starting season*

Passing

Rushing

Sack adjusted?

completions

attempts

Comp %

passing yards

YPA

TD

INT

Carries

Yards

YPC

TD

No

230

362

63.53%

2940

8.12

21

10

36

-38

-1.06

0

Yes

230

378

60.85%

2826

7.48

21

10

20

76

3.80

0

I think a real measure of Cousins as a passer is even after adjusting his passing stats downward like this, you still get a guy with a 61% completion percentage, 7.5 yards an attempt, and a 2:1 TD to INT ratio.
On the other hand, Cousins final rushing stats are pretty heavily skewed by a couple of crazy-legs scrambles (put this way, he had 228 career rushing yards after adjusting for sacks and 62 of those yards, 27% percent, came on just 2 of his 59 career carries), but lord, what crazy-legged scrambles those were.
*his last year, Cousins played 14 games instead of 13. I was going to adjust his total numbers for this, but then I remembered he missed a full game in 2009. '39 career start = 39 career starts' was my basic decision and I just kept them how they were. I don't thinnnkkkk it's a big deal in the end.

Andrew Maxwell

Passing

Rushing

Sack adjusted?

Completions

Attempts

Comp %

Yards

YPA

TD

INT

Carries

Yards

YPC

TD

No

234

446

52.47%

2606

5.84

13

9

37

-106

-2.86

0

Yes

234

467

50.11%

2450

5.25

13

9

16

50

3.125

0

Like lots of teams who want run-pass balance, a quick sanity check for how MSU did on the year is number of drop backs by the QB, and obviously ~470 for Maxwell in 13 games indicated some problems that showed up in 2012's final record, particularly at 5.25 yards a pop. Yikes.
When Maxwell chose to scramble he wasn't quite the golem his non sack adjusted numbers would lead you to believe. Of course, he basically never chose to scramble, and MSU certainly wasn't calling designed run plays for him.

Connor Cook**

Passing

Rushing

Sack adjusted?

completions

attempts

Comp %

passing yards

YPA

TD

INT

Carries

Yards

YPC

TD

No

207

353

58.68%

2559

7.25

20

6

64

71

1.10

1

Yes

207

368

56.31%

2443

6.64

20

6

49

187

3.79

1


The average of about 7.5 yards that Cook lost on each sack rightfully drags down his YPA to a more reasonable looking number and probably ditto on completion percentage though he improved greatly in that respect as the year wore on.
How significant sophomore Connor Cook has been towards MSU's QB getting involved in the run game is less obvious from his YPC number, nearly identical to Cousins career number', but more obvious when you see that he maintained that basically identical average over about 2.5 times as many 'true' carries. Also, he was smack in the middle of Nick Hill and Delton Williams as MSU's #3 run option, (fun fact: Cook had more carries in 2013 than Larry Caper and Nick Hill had, combined, in 2012). Needless to say, that 3.79 YPC number reflects what Cook was as a run-threat (lots of 3 or 4 yard gains) much better than the 1.1 number does.
**For ease of QB to QB comparisons, Cook's numbers have been adjusted as though he played 13 games while still accounting for his 14 games of production. Basically, his total season numbers have each been adjusted downward by ~7%, while the averages, of course. remain identical.

Sack adjusting the Michigan State offense.

Sack and non sack adjusted Dantonio Era

Passing

Rushing

Year

Sack Adjusted

Attempts

Yards

YPA

Carries

Yards

YPC

Run %

2007

No

393

2842

7.23

580

2576

4.44

59.61%

Yes

423

2649

6.26

550

2769

5.03

56.53%

2008

No

399

2773

6.95

511

1692

3.31

56.15%

Yes

423

2577

6.09

487

1888

3.88

53.52%

2009

No

423

3502

8.28

419

1779

4.25

49.76%

Yes

437

3420

7.83

405

1861

4.60

48.10%

2010

No

373

3073

8.24

444

1978

4.45

54.35%

Yes

397

2877

7.25

420

2174

5.18

51.41%

2011

No

451

3535

7.84

489

1931

3.95

52.02%

Yes

468

3430

7.33

472

2036

4.31

50.21%

2012

No

465

2729

5.87

492

1942

3.95

51.41%

Yes

487

2562

5.26

470

2109

4.49

49.11%

2013

No

430

2964

6.89

569

2433

4.28

56.96%

Yes

447

2837

6.35

552

2560

4.64

55.26%

All that data can be compressed into something more manageable like so:

Average Dantonio Era Offensive Year, sack adjusted

Passing

Rushing

Sack Adjusted

Attempts

Yards

YPA

Carries

Yards

YPC

Run %

No

419

3060

7.3

501

2047

4.09

54.43%

Yes

440

2907

6.6

479

2200

4.59

52.13%

So we're talking tangible shifts of like, a perceived half a yard to three-quarters of a yard here, as well as an almost two and a half percent shift in perceived run-pass balance, all due to score-keeping these passing attempts as running attempts. In a world where more and more QBs are picking up big yards on the ground, properly score-keeping sacks also more accurately assesses that position as a running threat at a glance. Many of the stat questions in college football (yards in the air vs yards after catch on pass plays, QB rush yards on scrambles vs designed runs, how much is a QB really under pressure, even when he isn't sacked, defensive yards per attempt at the individual DB level) require a bunch of time-consuming film study. This fix doesn't.

In the future, I'm curious to look at sack-adjusted data beyond just the Spartans (someone like Devin Gardner is a much better case study than Cook, for example), at the Big Ten, and maybe even the national levels, to see if I can get a better idea of how much of an perception effect this has on college football as a whole. Off-season project, maybe.

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