Writers of Pro Football Prospectus 2008

Most Recent FO Features

RiceSid07.jpg

» Sidney Rice: What Could Have Been?

Sidney Rice has retired. Is he the most random single-season DYAR leader ever? One-year wonder? Injury prone? We offer a career retrospective for the second-best wide receiver named Rice in NFL history.

25 Apr 2014

2013 Quarterbacks: True Sack Rate

by Scott Kacsmar

Arguably, the worst play a quarterback can make is throwing an interception. However, there are high amounts of luck and randomness involved with the rate at which interceptions occur. Sometimes the pass was tipped by the intended receiver. Sometimes the quarterback gets hit as he's throwing. Then you have the dozens of awful passes each season that should have been intercepted, but were dropped by defenders (reminding us why they play defense).

There's another type of play with negative consequences that is a much better predictor of future quarterback performance. The sack is a more common event that carries far less variation than the myriad of possibilities that come after a pass leaves the quarterback's hand. On these plays, the whole problem is the ball never did come out, and if it did, then we're looking at a fumble too.

Yet in all my years of following the NFL, it always seems like the sacks and fumbles are ignored in favor of the interception when it comes to analysis of a quarterback's mistakes. The sack is almost like a litmus test for where a fan is in their understanding of the game. Usually you start out thinking it's all about the offensive line and protection, but the sack is actually very dependent on the quarterback.

Peyton Manning led all quarterbacks in sack rate (2.66 percent) in 2013. Since entering the league in 1998, Manning has seven of the top 18 seasons in sack rate in that time. You can look at any other quarterback stat and Manning did not finish as high that frequently as he has with sack rate. Last year lowered his career rate to 3.10 percent, putting him above Dan Marino (3.13 percent) for the NFL record. As we looked at last year, Marino's quick release led to the greatest individual dominance of a stat in NFL history. He led the league in sack rate in seven consecutive seasons (1983-89) and 10 times overall.

Terrelle Pryor was just traded from Oakland to Seattle. Last season, he had a league-worst 10.23 percent sack rate. The Raiders were a mess at offensive line, but rookie Matt McGloin still managed a 2.77 percent sack rate (Manning territory) when he played. It's not like the Raiders magically blocked that much better for McGloin.

Since 2004, a quarterback has thrown at least 200 passes in back-to-back seasons 219 times. Here are the year-to-year correlation coefficients for six rate statistics in the passing game:

Year-to-year correlation (2004-13)
Statistic Year-to-year correlation
Completion percentage 0.54
Sack rate 0.52
Yards per attempt 0.47
Passer rating 0.42
Touchdown percentage 0.35
Interception percentage 0.05

See how untrustworthy interceptions can be? While a (usually young) player can certainly improve on limiting turnovers, it's the traits like accuracy and getting rid of the ball that are really more in his control.

To put it another way, sack avoidance is a great quarterback skill and most of the sacks that are taken are due to a failure in protection. But when the stat is presented for a quarterback's sack rate, it's an injustice to simply calculate sacks divided by the sum of passes and sacks. We looked at True Sack Rate last year and now return with the 2013 data that aims to quantify the rate at which quarterbacks are sacked.

2013's True Sack Rate

At its core, a sack is simply a pass play where the quarterback failed to get rid of the ball and gain positive yardage. A proper rate stat would include all of those plays, but the generic sack rate ignores scrambles on passes. From game charting, we add those scrambles along with counting intentional grounding penalties as sacks. After all, it's a quarterback under pressure, taking a loss of yardage. Those are even deadlier than the average sack due to the yardage involved. In January's wild AFC Wild Card game, the Chiefs' game-winning drive attempt was thwarted in large part to a 10-yard intentional grounding penalty charged to Alex Smith after pressure from Cory Redding. That set up a third-and-17 and knocked the Chiefs out of field-goal range. Smith actually would have saved at least three yards by taking the sack.

The following table sorts the leaders in True Sack Rate for all 37 qualified (minimum 224 pass attempts) passers in the 2013 regular season. General sack rate (Sack%) is also included with its ranking order. The number of accepted intentional grounding (IG) penalties is followed by the pass plays on which the quarterback scrambled (SCRAM). We also included just how many times the quarterback was under pressure (PRES) on those scrambles to differentiate from coverage scrambles or when a hole opened up. Stats are not adjusted for opponent.

Rk Quarterback Passes Sacks Sack% Rk IG SCRAM PRES Pct. TOT Passes True Sack Rate
1 Peyton Manning 659 18 2.66% 1 1 0 0 - 677 2.81%
2 Matthew Stafford 634 23 3.50% 2 3 11 6 54.5% 668 3.89%
3 Josh McCown 224 11 4.68% 3 0 8 7 87.5% 243 4.53%
4 Andy Dalton 586 29 4.72% 4 1 25 11 44.0% 640 4.69%
5 Jason Campbell 317 16 4.80% 5 1 12 7 58.3% 345 4.93%
6 Andrew Luck 570 32 5.32% 8 0 43 27 62.8% 645 4.96%
7 Philip Rivers 544 30 5.23% 7 0 15 7 46.7% 589 5.09%
8 Jay Cutler 355 19 5.08% 6 1 13 10 76.9% 387 5.17%
9 Ryan Fitzpatrick 350 21 5.66% 12 0 29 18 62.1% 400 5.25%
10 Sam Bradford 262 15 5.42% 10 0 7 4 57.1% 284 5.28%
11 Drew Brees 650 37 5.39% 9 1 12 7 58.3% 699 5.44%
12 Matt Cassel 254 16 5.93% 13 0 11 10 90.9% 281 5.69%
13 Matt Schaub 358 21 5.54% 11 1 4 1 25.0% 383 5.74%
14 Tom Brady 628 40 5.99% 14 1 3 1 33.3% 671 6.11%
15 Tony Romo 535 35 6.14% 15 1 8 3 37.5% 578 6.23%
16 Aaron Rodgers 290 21 6.75% 20 0 18 12 66.7% 329 6.38%
17 Matt Ryan 651 44 6.33% 16 2 8 6 75.0% 703 6.54%
18 Ben Roethlisberger 584 42 6.71% 19 0 14 8 57.1% 640 6.56%
19 Alex Smith 508 39 7.13% 23 1 46 23 50.0% 593 6.75%
Rk Quarterback Passes Sacks Sack% Rk IG SCRAM PRES Pct. TOT Passes True Sack Rate
20 Carson Palmer 572 41 6.69% 18 2 5 4 80.0% 618 6.96%
21 Joe Flacco 614 48 7.25% 24 0 15 9 60.0% 677 7.09%
22 Case Keenum 253 19 6.99% 21 1 5 3 60.0% 277 7.22%
23 Chad Henne 503 38 7.02% 22 2 11 7 63.6% 552 7.25%
24 Eli Manning 551 39 6.61% 17 5 6 5 83.3% 596 7.38%
25 Robert Griffin 456 38 7.69% 25 2 37 27 73.0% 531 7.53%
26 Kellen Clemens 242 21 7.98% 26 0 9 8 88.9% 272 7.72%
27 Cam Newton 473 43 8.33% 28 0 38 26 68.4% 554 7.76%
28 Colin Kaepernick 416 39 8.57% 30 0 47 27 57.4% 502 7.77%
29 EJ Manuel 306 28 8.38% 29 1 26 14 53.8% 360 8.06%
30 Nick Foles 317 28 8.12% 27 2 18 6 33.3% 363 8.26%
31 Geno Smith 443 43 8.85% 32 0 31 17 54.8% 517 8.32%
32 Ryan Tannehill 588 58 8.98% 33 0 14 10 71.4% 660 8.79%
33 Mike Glennon 416 40 8.77% 31 2 12 7 58.3% 468 8.97%
34 Russell Wilson 407 44 9.76% 35 2 51 33 64.7% 502 9.16%
35 Christian Ponder 239 27 10.15% 36 0 25 10 40.0% 291 9.28%
36 Brandon Weeden 267 27 9.18% 34 1 7 2 28.6% 301 9.30%
37 Terrelle Pryor 272 31 10.23% 37 2 34 17 50.0% 337 9.79%
AVERAGES 440.4 31.4 6.65% - 1.0 18.3 10.8 59.0% 490.1 6.60%

Rankings for the two sack rates barely change with the cumulative averages being 0.05 percentage points apart. That's to be expected given no quarterback can make his living off more than a couple of scrambles per game. What matters are the improved rates. Christian Ponder (+0.87%) had the biggest improvement. He was one of the more willing scramblers.

Eli Manning had the most negative change, dropping seven spots (-0.77%) in True Sack Rate thanks in part to his league-leading five intentional grounding penalties. He even had three in one game (Week 5 vs. Eagles). No quarterback since 2001 had more than two intentional grounding penalties in the same game. The average season only has about 35 grounding penalties, so they are not common at all. Eli's been charged with 11 since 2011 -- five more than runner-up Tom Brady. Eli's brother Peyton has eight intentional grounding penalties in his 240-game career.

Peyton Manning was also the only quarterback included here not to scramble once on 677 plays. For the second year in a row, Russell Wilson led all quarterbacks in scrambles to earn his "second coming of Fran Tarkenton" reputation. He had 50 as a rookie and 51 in 2013. He did face an above-average amount of pressure on the scrambles, but the highest rate belongs to Matt Cassel, who scrambled 11 times with 10 pressures. Nick Foles was one of the more notable names to have a low pressure rate, scrambling 18 times with six pressures (33.3 percent). He definitely showed more mobility in Chip Kelly's offense than expected and does not like to force passes.

2013 Sack Breakdown

Quarterbacks do react differently to pressure and some handle it better than others on a consistent basis. Now that we have a better sack rate, we can still break down the sacks even further through game charting to get a sense of the quarterback's sack avoidance skill.

Here's a brief guide to the sack categories in our charting:

  • Blown Block (BLOWN): Clear physical breakdown in protection that leads to the sack.
  • Coverage Sack (COV): A quarterback held the ball too long on a sack with sufficient protection.
  • Rusher Untouched (RUT): Often a blown assignment, these are the ugly plays where a rusher has a free run at the quarterback.
  • Other Pressure (OPRES): I lumped together plays that were charted as "Overall Pressure" (could mean multiple rushers) or "Blown Block/Rusher Untouched" (both could happen on same play).
  • QB Fault (QBF): Any time a quarterback "sacks himself" by tripping on his own feet, his lineman's feet, or just dropping the ball without being hit.
  • Failed Scramble (FS): On a pass play, the quarterback tried to scramble -- more because he saw room in front of him, as opposed to scrambling due to heavy pressure -- but the hole closed before he reached the line of scrimmage.

The following table shows how the 1,295 sacks in the 2013 regular season were marked in charting:

FO Charting Breakdown: 2013 Sacks
Sack Type Total Pct.
Total Sacks 1295 -
Blown Block 743 57.37%
Coverage Sack 264 20.39%
Rusher Untouched 174 13.44%
Other Pressure 75 5.79%
QB Fault 13 1.00%
Failed Scramble 26 2.01%

If we conclude that the coverage sacks and failed runs are mostly on the quarterback, then 76.6 percent of the sacks in 2013 were mostly due to protection failures. However, we know it's never as simple as the math suggests. Some quarterbacks do a much better job of helping the protection by getting rid of the ball quickly. An offense's usage of play-action and more deep routes will have a direct impact on the time the quarterback has to hold the ball, which will skew the sack numbers a bit.

Still, we know some quarterbacks are taking bad sacks that would have been avoided by a different player. Case Keenum lost 23 yards on one sack in the fourth quarter against Arizona last year. Good luck getting Tom Brady down for that type of loss. He'd never retreat that far back.

Mobility is actually one of the most overrated attributes for a quarterback when it comes to avoiding sacks. The signal callers with excellent footwork in the pocket, capable of quickly identifying a target and releasing are the best at avoiding sacks. It doesn't matter that they couldn't break five seconds in a 40-yard dash. History has shown most of the highly sacked quarterbacks were mobile guys unwilling to give up on the play.

With that in mind, we'll conclude with a look at the 2013 breakdown by sack type for all 42 quarterbacks with at least 10 sacks taken.

Quarterback BLOWN Pct. COV Pct. RUT Pct. OPRES Pct. QBF Pct. FS Pct. Total
Peyton Manning 17 94.4% (1) 0 0.0% (42) 0 0.0% (39) 0 0.0% (31) 1 5.6% (3) 0 0.0% (15) 18
Carson Palmer 33 80.5% (2) 2 4.9% (38) 2 4.9% (36) 3 7.3% (14) 1 2.4% (9) 0 0.0% (15) 41
Sam Bradford 12 80.0% (3) 1 6.7% (37) 1 6.7% (33) 0 0.0% (31) 0 0.0% (13) 1 6.7% (7) 15
Matt Schaub 16 76.2% (4) 1 4.8% (39) 1 4.8% (37) 3 14.3% (4) 0 0.0% (13) 0 0.0% (15) 21
Matt Ryan 33 75.0% (5) 5 11.4% (30) 4 9.1% (29) 1 2.3% (29) 1 2.3% (10) 0 0.0% (15) 44
Jake Locker 12 75.0% (5) 3 18.8% (26) 1 6.3% (35) 0 0.0% (31) 0 0.0% (13) 0 0.0% (15) 16
Ryan Tannehill 43 74.1% (7) 6 10.3% (32) 6 10.3% (25) 2 3.4% (24) 0 0.0% (13) 1 1.7% (14) 58
Drew Brees 27 73.0% (8) 1 2.7% (41) 4 10.8% (24) 5 13.5% (5) 0 0.0% (13) 0 0.0% (15) 37
Andrew Luck 23 71.9% (9) 3 9.4% (35) 4 12.5% (21) 2 6.3% (16) 0 0.0% (13) 0 0.0% (15) 32
Christian Ponder 19 70.4% (10) 7 25.9% (16) 1 3.7% (38) 0 0.0% (31) 0 0.0% (13) 0 0.0% (15) 27
Eli Manning 27 69.2% (11) 4 10.3% (33) 4 10.3% (26) 4 10.3% (9) 0 0.0% (13) 0 0.0% (15) 39
Tom Brady 27 67.5% (12) 6 15.0% (29) 5 12.5% (21) 2 5.0% (20) 0 0.0% (13) 0 0.0% (15) 40
Philip Rivers 20 66.7% (14) 8 26.7% (14) 0 0.0% (39) 1 3.3% (25) 0 0.0% (13) 1 3.3% (11) 30
Ben Roethlisberger 28 66.7% (13) 9 21.4% (21) 3 7.1% (31) 2 4.8% (21) 0 0.0% (13) 0 0.0% (15) 42
Chad Henne 25 65.8% (15) 3 7.9% (36) 7 18.4% (13) 2 5.3% (17) 1 2.6% (7) 0 0.0% (15) 38
Ryan Fitzpatrick 13 61.9% (16) 1 4.8% (39) 0 0.0% (39) 2 9.5% (11) 1 4.8% (4) 4 19.0% (1) 21
Alex Smith 24 61.5% (17) 9 23.1% (19) 4 10.3% (26) 2 5.1% (19) 0 0.0% (13) 0 0.0% (15) 39
Tony Romo 21 60.0% (18) 7 20.0% (24) 6 17.1% (17) 1 2.9% (26) 0 0.0% (13) 0 0.0% (15) 35
Jay Cutler 11 57.9% (19) 2 10.5% (31) 5 26.3% (3) 1 5.3% (18) 0 0.0% (13) 0 0.0% (15) 19
Kellen Clemens 12 57.1% (20) 2 9.5% (34) 7 33.3% (2) 0 0.0% (31) 0 0.0% (13) 0 0.0% (15) 21
Jason Campbell 9 56.3% (21) 5 31.3% (7) 2 12.5% (21) 0 0.0% (31) 0 0.0% (13) 0 0.0% (15) 16
Quarterback BLOWN Pct. COV Pct. RUT Pct. OPRES Pct. QBF Pct. FS Pct. Total
Andy Dalton 16 55.2% (22) 5 17.2% (27) 5 17.2% (16) 3 10.3% (8) 0 0.0% (13) 0 0.0% (15) 29
Aaron Rodgers 11 52.4% (23) 6 28.6% (11) 2 9.5% (28) 0 0.0% (31) 0 0.0% (13) 2 9.5% (5) 21
Joe Flacco 25 52.1% (24) 11 22.9% (20) 9 18.8% (11) 2 4.2% (22) 1 2.1% (12) 0 0.0% (15) 48
Brandon Weeden 14 51.9% (25) 8 29.6% (9) 2 7.4% (30) 2 7.4% (13) 0 0.0% (13) 1 3.7% (9) 27
Cam Newton 22 51.2% (26) 15 34.9% (3) 3 7.0% (32) 3 7.0% (15) 0 0.0% (13) 0 0.0% (15) 43
Colin Kaepernick 19 48.7% (27) 11 28.2% (12) 5 12.8% (20) 1 2.6% (28) 0 0.0% (13) 3 7.7% (6) 39
Matthew Stafford 11 47.8% (28) 6 26.1% (15) 5 21.7% (8) 0 0.0% (31) 1 4.3% (5) 0 0.0% (15) 23
Michael Vick 7 46.7% (29) 3 20.0% (24) 1 6.7% (33) 3 20.0% (3) 1 6.7% (2) 0 0.0% (15) 15
Matt Flynn 11 45.8% (30) 5 20.8% (23) 5 20.8% (10) 3 12.5% (6) 0 0.0% (13) 0 0.0% (15) 24
Josh McCown 5 45.5% (31) 3 27.3% (13) 0 0.0% (39) 0 0.0% (31) 1 9.1% (1) 2 18.2% (2) 11
Russell Wilson 20 45.5% (31) 14 31.8% (6) 8 18.2% (14) 1 2.3% (29) 1 2.3% (10) 0 0.0% (15) 44
Nick Foles 12 42.9% (33) 10 35.7% (2) 4 14.3% (19) 1 3.6% (23) 0 0.0% (13) 1 3.6% (10) 28
Robert Griffin 16 42.1% (34) 11 28.9% (10) 9 23.7% (5) 1 2.6% (27) 0 0.0% (13) 1 2.6% (12) 38
Mike Glennon 16 40.0% (35) 13 32.5% (5) 7 17.5% (15) 3 7.5% (12) 1 2.5% (8) 0 0.0% (15) 40
EJ Manuel 11 39.3% (36) 11 39.3% (1) 6 21.4% (9) 0 0.0% (31) 0 0.0% (13) 0 0.0% (15) 28
Thad Lewis 7 38.9% (37) 6 33.3% (4) 4 22.2% (7) 0 0.0% (31) 0 0.0% (13) 1 5.6% (8) 18
Case Keenum 7 36.8% (38) 4 21.1% (22) 8 42.1% (1) 0 0.0% (31) 0 0.0% (13) 0 0.0% (15) 19
Geno Smith 15 34.9% (39) 10 23.3% (18) 8 18.6% (12) 9 20.9% (2) 0 0.0% (13) 1 2.3% (13) 43
Blaine Gabbert 4 33.3% (40) 2 16.7% (28) 2 16.7% (18) 4 33.3% (1) 0 0.0% (13) 0 0.0% (15) 12
Terrelle Pryor 9 29.0% (41) 8 25.8% (17) 7 22.6% (6) 3 9.7% (10) 1 3.2% (6) 3 9.7% (4) 31
Matt Cassel 3 18.8% (42) 5 31.3% (7) 4 25.0% (4) 2 12.5% (6) 0 0.0% (13) 2 12.5% (3) 16

All but one of the 18 sacks taken by Peyton Manning were blown blocks. That's the highest rate in the league and he's the only quarterback here to not take a coverage sack. Many of the quarterbacks with a low rate of blown block sacks and high rate of coverage sacks are inexperienced (Terrelle Pryor, EJ Manuel, Mike Glennon and Thad Lewis) or just not very good (Cassel).

Cam Newton led the league with 15 coverage sacks. If he was waiting for guys like Steve Smith and Brandon LaFell to get open, then that might be a problem in 2014 with Jerricho Cotchery and Jason Avant currently leading the receiving corps.

Joe Flacco and Robert Griffin III had the most sacks with a rusher untouched (nine), but Keenum had the highest rate of his sacks happening that way. Houston signed Ryan Fitzpatrick this offseason, but he led the league with four failed scrambles resulting in sacks.

Yeah, the Texans could use a quarterback, but if the history of sack rates is any indication, Johnny Manziel's maverick style may keep him in David Carr territory (read: the bottom) on any future list of True Sack Rates.

Posted by: Scott Kacsmar on 25 Apr 2014

74 comments, Last at 29 Apr 2014, 9:28pm by Noah of Arkadia

Comments

1
by Vince Verhei :: Fri, 04/25/2014 - 1:05pm

"Case Keenum lost 23 yards on one sack in the fourth quarter against Arizona last year."

That was the longest sack of the 2013 season. Keenum also had the second-longest sack, a 19-yard loss against Jacksonville in Week 12. There were 14 sacks that lost 15 yards or more last year, and Keenum had four of them. Keep in mind he only played eight games.

2
by WeaponX :: Fri, 04/25/2014 - 1:19pm

Carolina's top receiver was and probably is a TE.

3
by iwatt :: Fri, 04/25/2014 - 2:25pm

Further evidence that Trestman is the QB whisperer: Cutler and McCown were both top 10, while in 2012 Cutler was near the bottom.

4
by Scott Kacsmar :: Fri, 04/25/2014 - 2:27pm

I'm sure Trestman deserves credit, but from our AGL study, the continuity for Chicago's OL was absurd in 2013. They almost had all 5 guys play every snap and keep in mind 4 of those guys were new starters in Chicago. So it was a whole different scheme and basically a whole different OL for Cutler to work with. Not just different, but superior as well.

6
by iwatt :: Fri, 04/25/2014 - 3:16pm

The pass protection improvement thing is real, but hard to quantify. FO has the Bears as top 5 at adjsuted sack rate (still weird to accept that as a Bears fan). But PFF has them at 28th at Pass Blocking Eficiency. All I know is that now the OL is competent, to say the least.

I know Cutler bugs you, since he keeps showing up on your Clutch list. As a Bears fan he bugs me as well. A, life of the fan of a high variance QB.

14
by Steve in WI :: Fri, 04/25/2014 - 4:17pm

I don't think you can overestimate the value of going from a terrible o-line to a competent one. My hunch is that the line the Bears had in 2012 was so bad that any QB would have gotten killed behind it. I'm not sure how much credit for a low sack rate should go to Cutler/McCown/Trestman and how much belongs to the greatly improved 2013 o-line, but I'd blame 99% of the problems from 2012 on Webb, Carimi, and company.

19
by tuluse :: Fri, 04/25/2014 - 4:41pm

Cutler had really low sack rates in Denver too.

44
by Karl Cuba :: Sat, 04/26/2014 - 2:01pm

Isn't this exactly what you would expect when moving from a downfield, digit system passing game to a west coast, quick passing attack?

39
by Chip :: Sat, 04/26/2014 - 8:56am

The improved sack rate is all Trestman.

Cutler had the 5th highest pressure rate (76%) in the league (Josh M. was 6th) - see top chart. Cutler also had the 3rd highest untouched rusher rate (23%). Both of these stats lay the blame on the O-line which would explain PFFs 28th ranked pass efficiency.

5
by nat :: Fri, 04/25/2014 - 2:33pm

Not bad, Scott. You still miss on interpreting the final table, but not as badly as some would.

You imply that Denver's line had the highest rate of "Blown Blocking Sacks" in the league. Of course, that's completely wrong. They only had 17 such sacks on a total of 677 plays. That's about the 5th best rate in the league. You get a point for not actually saying explicitly that the line was bad. Because being fifth best is actually really, really good.

8
by Dr. Mooch :: Fri, 04/25/2014 - 3:23pm

I think he was actually implying that a high percentage of blown block sacks is a sign of QB skill, rather than anything about the offensive line.

30
by nat :: Fri, 04/25/2014 - 5:38pm

If that was what he was trying to do, he picked a weak and convoluted stat for the purpose.

The whole concept is that "blown block sacks" have little to do with QB skill and a lot to do with line play. So comparing coverage sacks to blown block sacks (that's what Scott is doing in effect) clouds the QB skill picture rather than making it clearer.

Remember: a bad QB can play behind a bad line. His "BLOWN Pct." number would be average, just like a good QB behind a good line.

31
by Perfundle :: Fri, 04/25/2014 - 8:37pm

Every single QB save one with an unforced sack rate (defined as the percentage of coverage sacks, failed scrambles, intentional groundings and QB fault sacks out of total pass attempts) of higher than 1.7% has a blown block rate of lower than 57%, and every single QB save two with an unforced sack rate of lower than 1.7% has a blown block rate of higher than 57%, and the correlation coefficient is -0.757, which seems pretty strong to me.

32
by Dr. Mooch :: Fri, 04/25/2014 - 8:48pm

No nat, you're just badly misinterpreting the statistic as somehow about the offensive line, when it's entirely about the QB. The best QB in the world would have 100% blown blocks. ALL of his sacks would be the O-line's fault, even if it's a very good line that only does it 17 times a season. But with the perfect QB no sacks would be coverage sacks where he held the ball too long. None would be untouched rushers where he failed to make his hot read, and none would be failed scrambles where he misjudged his chances of getting away. The only way a defender gets to the best QB is by beating a blocker.

56
by nat :: Mon, 04/28/2014 - 9:31am

The article defines "Blown Block Sack" as Clear physical breakdown in protection that leads to the sack.

That has nothing to do with the quarterback. It's a stat about the OL. That's its purpose.

While it is true that the "best QB in the world" would have a high ratio of blown block sacks to other sacks, it is equally true that he would have a high ratio of left guard's Body Mass Index to other sacks, number of teammates with names containing three vowels to other sacks, team's field goals made to other sacks... none of which are good stats to judge a QB's ability to avoid sacks.

However, when you compare to the league averages (always a good FO technique) you would see that Denver's OL prevented more blown block sacks than any team but one (and fifth best in rate), and the combined efforts of Manning, the OL, and the receivers prevented more coverage sacks than any other team. The difference between those two numbers is not very remarkable: just 1.7 sacks over the course of the season.

Even if you give Peyton ALL the credit for avoiding coverage sacks, which would be silly since it's a stat about receivers having time to get open as much as about QBs throwing the ball away to avoid sacks, you would still have to conclude that he and his line pretty much split the credit for the team's low sack rate.

Overall, the Blown Block Sack percentage fails to measure the rate at which block block sacks happen, and fails to measure the relative contributions to pass protection of the line and QB. It's a useless stat and bad analysis in an otherwise fine article.

58
by Scott Kacsmar :: Mon, 04/28/2014 - 10:18am

Purpose was never about the OL, hence OL is not in the title of the article. You're making the last table into something more than it is. It's not like all blown blocks or all untouched rushers are included to derive rates from. It's simply a breakdown of the sacks taken last season. Ideally, you'd want a QB who only gets sacked when his OL sucks (Blown Blocks) and not a QB who takes a lot of unnecessary sacks because he can't/won't get rid of the ball, isn't a wise scrambler or is a bumbling, stumbling fool. If most of your sacks are from blown blocks, then that means the QB won't have a lot of the sacks that are more about his mistakes. Simple as that.

62
by nat :: Mon, 04/28/2014 - 11:22am

Ideally, you'd want a QB (and receivers and line) that has a lower rate of coverage sacks per dropback. That's what helps you win games, not a ratio to an unrelated number.

Ideally, you'd want a line (and a little bit of QB) that has a lower rate of giving up blown block sacks per dropback. That's what helps you win games, not a ratio to an unrelated number.

The ratio to each other or to total sacks tells you very little about either. You can have a lower coverage sack % (using your ratio to total sacks) by avoiding coverage sacks, or by having a bad line. You can have a higher blown block % by having a bad line or by avoiding other kinds of sacks.

Since the percentages you use are mostly useless to judge either the line or the QB, we might suppose that you intended them to judge the relative value of each. Sadly, the stat fails at that, too. Being good at avoiding coverage sacks saved the Broncos about 9 sacks last year. Being good at avoiding blown blocks saved about 8 sacks last year. The two phases of sack-avoidance contributed about the same amount to the Bronco's success at pass protection. The 94.4 percentage you focus on at the end of the article is completely misleading as a comparison tool, and hopeless as a tool for ranking QBs.

The rest of the article was fine.

It would be refreshing if you just admitted your mistake in using that bad stat to rank QBs in a way that just doesn't work. Instead of touting Denver as having the "highest rate in the league" of blown block sacks, you could truthfully say that they have the fifth lowest rate in the league, and had a line and QB that - by these stats - contributed nearly equally to their success in pass protection.

Or are you going to insist that the Broncos OL "sucks"?

63
by Scott Kacsmar :: Mon, 04/28/2014 - 12:04pm

I'm not going through this again with you. There's value to breaking down stats like completions and sacks. Not everything has to be about the overall rate every single time.

As for Denver specifically, I see no reason to give the OL much credit for the sack numbers when the QB is such an outlier in that department. Marino was the same way in his era. No matter how many different OL combinations you put in front of these guys, they are the hardest to sack. Given Ryan Clady (the best they have) missed practically all of the season, they were down to their third center, their RT was demoted at season's end and they let Beadles walk in free agency, I'm not inclined to call this an elite unit.

When Denver failed in 2013, the OL was a weakness. It was always a quick edge pressure too: the safety in Indy and then three plays (all in crucial spots) where Manning was hit as he threw and the ball was easily intercepted (IND, SD, SEA). None of those were bigger than in the Super Bowl for the pick-six. Maybe another QB eats the ball there and punts, keeping the game at 15-0 and perhaps competitive for the final 33 minutes. Maybe that's a flaw in Manning's game where he is too determined to not take sacks. If you want to say that shined through on the Tracy Porter play or the pick in OT against Baltimore, I won't disagree. But we're still taking about a QB skill and not his OL.

Now I don't think the Denver OL was bad, but any other QB in the league would not have replicated the sack numbers Manning had behind them.

67
by nat :: Mon, 04/28/2014 - 4:08pm

As for Denver specifically, I see no reason to give the OL much credit for the sack numbers when the QB is such an outlier in that department.

Wow. Just wow. The unprofessional fanboy-level bias rears its ugly head. Wow.

I gave you credit for making an honest analysis mistake. It's now obvious that you were dishonestly trying to warp the data to fit your personal narrative. And if you can't warp the data or get caught doing it, you just claim special dispensation to ignore the data you don't like entirely. Why? Because Peyton must get all the credit. Because 0 coverage sacks is so godlike, that it has to mean the OL gets not credit for their excellent work. Because OMG PEYTON!

Manning may have had zero coverage sacks, but there are a fourteen QBs with three or fewer, and sixteen guys with coverage sack rates of under 1%. Zero percent, as good as it is, isn't some godlike outlier stat that justifies treating Denver as some unique special case.

Your own data shows that the Denver OL was very, very good at avoiding sacks that would have been their fault. Not just the low "blown block" number, but the "rusher untouched" and "other pressure" zeroes, too. So you focus on a bogus ratio stat, and when called on it, you just make stuff up, pushing every bad thing onto the OL, and deflecting any credit they should get to the QB.

Jeez. What a hack.

68
by Karl Cuba :: Mon, 04/28/2014 - 6:03pm

Why are you being so rude? If you have such a problem then perhaps you should write your own damn article.

Jeez. What a pillock.

69
by theslothook :: Mon, 04/28/2014 - 7:02pm

Honestly, perfundle said it best, you only have a problem with this if you missed the the context of this article. Since it is very clearly a ranking of quarterbacks based on the type of sacks they take,theres no pt to turn those stats as an indictment against the o line and call the whole thing misleading. But thats how hes chosen to interpret it. If anything, this feels agenda driven on nats part since hes focused solely on Denver being misleading rather than o lines in general

71
by Scott Kacsmar :: Mon, 04/28/2014 - 8:03pm

Typical gnat. This goes on in practically every article, and since I'm not contractually obligated to respond, we should just let him keep punching the coffin wood. Maybe one day he'll break out and write his own article.

73
by nat :: Tue, 04/29/2014 - 1:29pm

How mature.

74
by Noah of Arkadia :: Tue, 04/29/2014 - 9:28pm

Only logical explanation is you killed some kittens in a past life. By the looks of it, they were nat's kittens.

------
The man with no sig

10
by Perfundle :: Fri, 04/25/2014 - 4:02pm

Oh geez, not this again. Why do you insist on misinterpreting the data when it's perfectly clear from context what the stat means in this case?

20
by tuluse :: Fri, 04/25/2014 - 4:42pm

Nat is right. Denver doesn't blow blocks very often compared to other teams in the league, yet from the information presented it looks like they do.

23
by Perfundle :: Fri, 04/25/2014 - 4:45pm

It only looks like it if you don't read the article at all. The point of the article is how much QBs are responsible for their sacks, and that number tells me Manning is the least responsible. Nowhere in the article are offensive lines being compared to each other on their pass blocking abilities.

26
by tuluse :: Fri, 04/25/2014 - 4:48pm

The ranking is a comparison. That's what a ranking is.

Edit: I'm also pretty sure your conclusion is not supported by the data because it's probably well within the margin of error. However, when the data is presented as it is in this article it is not apparently that the differences are small and margin of error would account for it.

40
by Noah of Arkadia :: Sat, 04/26/2014 - 10:34am

The ranking, however, is comparing QBs, not O-lines. You could compare O-lines with the presented information, however, by comparing the absolute number of blown blocks allowed.

------
The man with no sig

64
by FrontRunningPhinsFan :: Mon, 04/28/2014 - 12:59pm

I'm guessing you are trying to find reasons to believe Tannehill can get better, just like me. More sacks from blown blocks alone than all but 3 other QBs total is a start, right?

70
by Noah of Arkadia :: Mon, 04/28/2014 - 7:18pm

Darn right you are! The data seems to confirm what most observers already agree with, that the line blowed. It doesn't necessarily mean that Tanny is good in the pocket, but I guess we can call it a mistrial.

------
The man with no sig

27
by theslothook :: Fri, 04/25/2014 - 4:49pm

Im not sure I agree. The first table pretty clearly showed that Denver did not give up many sacks, thus naturally their oline will not have many blown blocks.

7
by Dr. Mooch :: Fri, 04/25/2014 - 3:22pm

With the exception of Glennon, those rookies with the low blown blocks and high coverage sacks were also low in untouched rushers.

Any ideas about what that means? Are we seeing more protection, so fewer receivers? Less blitzing and more coverage from the D? Rookies just holding the ball longer? I think we have numbers to test all of those hypotheses.

11
by Perfundle :: Fri, 04/25/2014 - 4:09pm

"With the exception of Glennon, those rookies with the low blown blocks and high coverage sacks were also low in untouched rushers. "

Huh? No they're not. Manuel is 9th, Smith is 12th, Griffin is 5th, and Wilson is 14th.

12
by Dr. Mooch :: Fri, 04/25/2014 - 4:15pm

My use of 'rookies' was incorrect. I should have said 'inexperienced,' as I was referencing this list from the article: "(Terrelle Pryor, EJ Manuel, Mike Glennon and Thad Lewis)" Glennon is 15th, and the other three 6th, 1st, and 4th.

15
by Perfundle :: Fri, 04/25/2014 - 4:17pm

So you mean high in untouched rushers?

17
by Dr. Mooch :: Fri, 04/25/2014 - 4:20pm

S'pose I do, yeah. Changes the hypotheses, then and more or less supports the idea that it's all just bad decision-making from the QBs.

22
by tuluse :: Fri, 04/25/2014 - 4:43pm

Conventional wisdom says rookies are slow to read coverages.

9
by SandyRiver :: Fri, 04/25/2014 - 3:41pm

Wonder how many of Brady's coverage sacks came early in the season with the JV receiving corps.

51
by Scott Kacsmar :: Mon, 04/28/2014 - 4:21am

Brady's 6 coverage sacks came in Weeks 1, 3, 5, 6, 9 and 17.

54
by SandyRiver :: Mon, 04/28/2014 - 8:12am

Thanks. I think it's worth noting that only one came with Gronk in the lineup, (the week 9 blowout of Pittsburgh.)

16
by Perfundle :: Fri, 04/25/2014 - 4:20pm

One thing that should be noted is that not all sacks are created equal. Keenum's 23-yard sack helped Houston have the worst average sack distance, at 8.8 yards. Carolina was also very bad, at 7.8 yards, and this even extended to the Pro Bowl when Newton got sacked 4 times for 36 yards. Meanwhile, San Francisco and Seattle only had 5.9 yards and 6.2 yards, respectively, because Kaepernick and Wilson often scrambled forward to prevent the sack from hurting so much; Wilson got sacked 3 times for 0 yards against the Saints in the playoffs, for example.

18
by theslothook :: Fri, 04/25/2014 - 4:24pm

I'm not the biggest Wilson fan( I strangely find him currently overrated but expect him to be really good in the future), but I think hes the best decision scrambler in the league, as evidenced by the stat of sack yards lost. He really does do a good job of knowing when to all out scramble and take off, scramble and then pass long, or scramble and throw away.

21
by Perfundle :: Fri, 04/25/2014 - 4:43pm

Personally I haven't seen him rated that highly. Most likely to get more Super Bowls, yes, but that's more a function of his supporting cast. And playing in the NFC West is certainly not helping him pad stats in any way.

But the 14 coverage sacks is pretty sobering, although I figured as much. I'd be really interested to see the air yards per pass attempt broken down by seconds held on to the ball, though. Do the long passes Wilson makes after scrambling for 5 seconds make up for all those coverage sacks?

24
by tuluse :: Fri, 04/25/2014 - 4:45pm

I have definitely seen Wilson be slow to recognized a defense and take a sack. It's both a good and a bad thing. It's worse to throw the pass when you don't know what's going on, but of course you'd rather have Peyton Manning making decisions.

29
by theslothook :: Fri, 04/25/2014 - 5:11pm

I agree, hes still very primitive in that respect. I was isolating just his decisions when hes decided to scramble. Basically, in these situations, he tends to make good decisions about not being case keenum..

34
by Jazzaloha :: Sat, 04/26/2014 - 1:02am

I have the same impression regarding Wilson being he best decision scrambler. On a related note, I think data including positive yards ran or thrown on scramble plays should also factored in, especially for scrambling QBs like Wilson, Roethlisberger and Rodgers. If positive offensive plays (especially significant ones, e.g, ten or more yards, let's say) occur a high percentage during scrambles, while negative plays (e.g., turnovers, sacks, particularly for big yards) make a far lower percentage, then I think that would give you a more accurate picture of the value of scrambling and mobility.

(By the way, was the stat for yards lost on a sack listed above, or did you get that from somewhere else?)

35
by Perfundle :: Sat, 04/26/2014 - 1:41am

I'm pretty sure Wilson's stats are better when he doesn't have to scramble. So if he is the reason he's scrambling in the first place, then it's a net negative.

36
by Jazzaloha :: Sat, 04/26/2014 - 3:08am

But suppose the choice was scrambling or taking a sack or even having to throw the ball away immediately? It seems like in every game there's a pass rusher that come shooting up toward that he has to evade (scramble), and if he doesn't he'd get crushed. That's just based on memory, so I don't know how reliable that is.

48
by Perfundle :: Sun, 04/27/2014 - 4:49pm

There's also the option of identifying an open receiver and throwing the ball to him right before he gets hit. It's true that he avoids the hit by scrambling, but I don't really know if a couple more hits per game is really that bad, especially when he throws it considerably less than most QBs.

37
by theslothook :: Sat, 04/26/2014 - 3:48am

I've long since decided that scrambling in just about any case is generally a sub-optimal choice for a qb to make. The fact that Manning can have basically no coverage sacks while having the mobility of a statute, tells me there is always an alternative to scrambling. That said, as Tuluse mentioned above, failing that, the next best option seems to be scrambling and making something happen. Obviously, take a sack for a loss or turning it over is the worst decision, but scrambling might lead to a first down or gain of positive yardage. In that respect, I think Wilson is the best. He doesn't throw ints but he also does a good job of deciding when it's time to scramble for a first down, when it's time to scramble and hang around to air it out, and when it's time to throw away. He's also really good at deciding when to run and dive or when to run out of bounds.

13
by theslothook :: Fri, 04/25/2014 - 4:17pm

I'm a bit suprised Luck finished 5th in sack rate. I know he gets hit a lot so his Roethlisburgeresqur abilities proobably overstates his true pocket awareness ability

25
by Sisyphus :: Fri, 04/25/2014 - 4:47pm

I have seen Luck play a lot and his pocket awareness is borderline spooky; he has tremendous feel for rushers coming from behind him. The Colts' offensive line has been horrible the past several years and getting worse, a steady degeneration. I am surprised he did not finish better.

As a further note, somewhat related, what do these results look like if you factor in average time for the sack? I would imagine a mild correlation that the lower sack rate quarterbacks also get sacked a lot faster. (This obviously penalizes the scamblers.)

28
by theslothook :: Fri, 04/25/2014 - 5:09pm

Its not that luck has poor pocket awareness, its just that hes content to hold the ball till he gets what he wants.

33
by Jazzaloha :: Sat, 04/26/2014 - 12:54am

Mobility is actually one of the most overrated attributes for a quarterback when it comes to avoiding sacks. The signal callers with excellent footwork in the pocket, capable of quickly identifying a target and releasing are the best at avoiding sacks.

Couple of comments:

1. I agree with the second sentence, but that's partially a function of the offense and the quality of receivers, isn't it? My sense is that some of the spread offenses (like the Broncos and Patriots) are specifically designed to negate the blitzing/pass pressure by getting rid of the ball quickly. In contrast, run-oriented offenses don't always have that, especially as you mention, for run action and deep routes. If you don't take into the offensive style, is it an apples to apples comparison?

2. Do the BLOWN and RUT numbers above also include instances when a sack did NOT occur? I ask because I would think the number of times a QB avoided a sack under either circumstance might suggest that mobility is important. Maybe my eyes are deceiving me, but I feel like Russell Wilson avoids a lot sacks in those situations, and even when these result in ball intentionally out of bounds or a short/zero gain, that's not an insignificant accomplishment.

Because of some of the issues I raised above, I'm not sure what to make of these stats, at least in relation to attributing blame to QBs or OLs.

38
by theslothook :: Sat, 04/26/2014 - 3:51am

I have an alternative take. To this day, Manning's best sack avoidance seasons actually came when his receivers were generally the weakest ( 08,09,10). Those years were also the colts weakest offensively, but he didn't get sacked as much. I think getting sacked, beyond the qb, is also a function of playcalling. In the case of those three years, the colts relied far more on quick passes rather than stretching the field and the result was a lower sack rate primarily because the offense couldn't move the ball any other way and was forced to avoid sacks. Ultimately, successful offenses will trade sack rate for higher dvoa via play calling, but it's less a receiver issue IMO.

42
by Jazzaloha :: Sat, 04/26/2014 - 1:19pm

I do think play calling is important. With Manning, I see play calling (especially his audibles) as part of the offense in general. He's run a pass-first offense and he's given the freedom to change plays like no other QB it seems. His ability to read defenses and find the right play, using guile at times, allows him really avoid or reduce sacks.

But I wouldn't underestimate the type of offense or the quality of his receivers in this equation. If he ran a more conventional run-first offense, with too receivers (let's say). And let's suppose those receivers couldn't get open by themselves (that is, they relied on schemes and formation shifts to get open)? Would he still be able to reduce/avoid sacks? I'm not so sure.

My sense is that a good run-first offense has a very different approach to dealing with pass pressure and reducing sacks. The running game is often instrumental in reducing the pass pressure, but delaying the pass rushers at the line. The passing attack is also different in that it relies on play action, which takes a while to develop and can be risky. (If the defender doesn't bite, a QB can get sacked with very little control over avoiding it.)(Edit: Traditionally, I think these offenses rely on receivers that can beat their defender one-on-one. So if you don't have at least one receiver like that, it can be rough.)

I don't know--I feel like the offensive systems need to be factored in to some degree when looking at sack statistics; as it can make for an apples-to-oranges situation.

41
by Red :: Sat, 04/26/2014 - 12:09pm

Scott, what are the year-to-year correlations for QB fumble rate? My sense is that fumbles are more consistent than INT's, but less than all the other stats.

43
by Karl Cuba :: Sat, 04/26/2014 - 1:57pm

I'd also like to know if interceptions correlate better if you include dropped picks in the total?

52
by Scott Kacsmar :: Mon, 04/28/2014 - 4:27am

My fumble rate stats are collected for career, not broken down by season, so I don't have the answer. I might be able to create something good on that from our play-by-play data though.

45
by Pen :: Sun, 04/27/2014 - 1:24am

How much of it is Wilson holding the ball due to longer routes or lack of receiver separation?

Peyton throws those quick outs. It's not like just because he has a quick release he's a better QB. (He is, of course, but we don't judge QB's by how great they are at short, quick passes). If that was all it took to be good, he wouldn't have gotten stomped in the Super Bowl. But tight man coverage and strong pass rush forced Manning to make many quick throws for little yardage. When he couldn't, well, we all saw the damage.

Wilson's offense doesn't run that way. Wilson scrambles to buy time for a play to develop. That means, by design, he's going to hold onto the ball longer. When a play doesn't develop, he gets sacked, or throws it away, or gets grounding, what have you. So my question is, since the team is trying to NOT do quick outs and let longer plays develop, how much of Wilson's coverage sacks are on him and how much on his receivers?

46
by Arkaein :: Sun, 04/27/2014 - 12:42pm

These numbers are good, but the analysis is seriously lacking when it comes to interceptions.

First of all, I think it's pretty clear that even though interceptions have a fairly low year-to-year correlation, that this is more a factor of sample size than relation to QB ability. Interceptions naturally occur less often than TDs and sacks, and much less often than passes thrown, so it's expected that year-to-year correlations would be lower even if interceptions are just as much determined by skill as these other stats.

For example, I just don't see Aaron Rodgers ever posting a 20 INT season, but the very low correlations listed would make this seem at least moderately likely. Another problem might be that year-to-year correlations ignore the fact that a QB with a very low career average interception percentage can show low year-to-year correlation, while still being objectively better at avoiding interceptions than another player with the same year-to-year correlation, but higher career percentage. With the same year-to-year correlations, I know which QB I'd take.

The second problem is that Kacsmar seems to believe that because interception rates vary more than sack rates, that this makes sacks more important than interceptions in assessing a quarterback. This is nonsensical to me. If interceptions were truly luck, then I'd agree, but career interception rates indicate that avoid interceptions is a skill (otherwise rates for players would converge to the NFL average over sufficiently long careers), and interceptions are alomost always more damaging than sacks, particularly when fumbles are penalized separately from sacks (sacks often lead to fumbles, but a QB who is above average at holding the ball when sacked should not be penalized for fumbles he doesn't commit). In any case, the importance of a skill is not determined by our ability to measure it, and as other have pointed out, raw interception numbers are fairly crude, ignoring factors outside the QB's control, like dropped picks and passes deflected by teammates.

47
by Jerry :: Sun, 04/27/2014 - 2:29pm

There have been 36 20+ interception seasons since 2000, 15 of which were from 2000-2003. So while it's reasonable to assume Rodgers won't have one, it's not unreasonable to assume that for any quarterback.

The interception rate is so low now that any given passer's year can contain a lot of noise. That would explain the low year-to-year correlation. Since there are more sacks, the data is somewhat more reliable.

49
by greybeard :: Sun, 04/27/2014 - 5:20pm

Is there a proven link between sack rate and team success? We know that sacks are bad but we never know what they replace or how much impact they have on the score. Both Wilson and Kaep have high sack rate, but they were the QBs for the two best teams and two out of three most successful teams in NFL last year.

Sacks are bad unless,
- You get first down or a TD in that same drive. Or it was a third down and there were no open receivers and you got a FG.
- There was no open receiver and it was third down and it was between 40s. In that case the QB did a good job in holding the ball as long as possible to extend the drive and the sack is not worse than incompletion. Punters easily get 50 yards gross.
- Sacks are bad but almost no different than an incompletion if the loss yards are a few. I see a lot time QBs scramble and try to find an open receiver and in the process go out of bounds just a few feet short. Those still count as sacks.
- Sacks are bad but are not as bad as interceptions unless the sack results in a fumble. So if a QB is taking a sack instead of forcing it, well you would rather have them throw away if they can but if they cannot a sack is better.
- sacks are bad unless you are quite ahead and milking the clock and playing conservatively.
I have not seen any proof of any strong predictive correlation between sacks and success.

50
by RickD :: Sun, 04/27/2014 - 5:35pm

"At its core, a sack is simply a pass play where the quarterback failed to get rid of the ball and gain positive yardage."

Should that 'and' be an 'or'? And should an 'either' be in there?

An incomplete pass is a play where the QB got rid of the ball but failed to get positive yardage.

A positive QB run is a play where the QB got positive yardage but failed to get rid of the ball.

Neither is a sack. And I'm pretty sure you don't want them included.

53
by Scott Kacsmar :: Mon, 04/28/2014 - 4:30am

I think your two examples show why it's an "and" in the sentence. Sack needs both requirements along with being a pass play. A QB draw that loses 2 yards would be credited as a minus-2-yard run.

57
by RickD :: Mon, 04/28/2014 - 10:12am

Not in English. Not when you're using a negation.

What you're saying is "a sack happens" when a QB failed to "get rid of a ball and gain positive yardage".

If a QB fails at either of those tasks, because of the AND he has failed to "get rid of the ball AND gain positive yardage."

An incomplete pass is a failure to "get rid of the ball AND gain positive yardage."

That's why it needs to be an OR. Then it's a QB "failed to get rid of the ball" OR "failed to gain positive yardage."

And that's what a sack is.

59
by Scott Kacsmar :: Mon, 04/28/2014 - 10:24am

It's early in the morning, I got two hours of sleep, but you've completely lost me here.

Since when does "and" not imply both things need to happen? You want to make a sentence that has two qualifiers become an either/or, which means only one thing is okay. That doesn't make any sense.

An incomplete pass is a failure to "get rid of the ball AND gain positive yardage."

No it's not. If the pass was incomplete, he got rid of it.

If we use or, you are saying both of these statements are correct:

"A pass play where the QB fails to get rid of the ball is a sack." (No, could be a scramble)
"A pass play where the QB fails to gain positive yardage is a sack." (No, could be an incompletion)

If you have a pass play where both of those things happen, then it can only be a sack.

60
by RickD :: Mon, 04/28/2014 - 11:13am

You probably don't want to do this on two hours of sleep.

You want to say neither A nor B happened. The way to do that is not to say NOT (A && B). NOT (A && B) means that it didn't happen that both A happened and B happened.

This is basic, first-year logic.

An incomplete pass is, indeed, a failure to "get rid of the ball and gain positive yardage."


"No it's not. If the pass was incomplete, he got rid of it."

But he didn't gain positive yardage. Therefore he didn't "get rid of the ball AND gain positive yardage." That's why I'm saying you need an OR there. You want to say "he failed to get rid of the ball" or "he failed to gain positive yardage". Hence "he failed to get rid of the ball or gain positive yardage".

First year logic: ~ (A & B) = (~A) v (~B). The question here is the scope of your qualifiers. I'm viewing "failure" as external to "get rid of the ball and gain positive yards" but you are thinking off it as "failure to get rid of the ball" AND "failure to gain positive yards". But that's not the natural interpretation, either in logic, or in the English language.

If you say a person has failed to do A & B, that failure is triggered if either A or B does not happen.

61
by RickD :: Mon, 04/28/2014 - 11:15am

Formally, this is known as De Morgan's Law.

http://en.wikipedia.org/wiki/De_Morgan's_laws

66
by SandyRiver :: Mon, 04/28/2014 - 3:50pm

Logical for the entire sentence, but the cognitive dissonance of "...incomplete pass is a failure to get rid of the ball..." is immense (to me, anyway.) Perhaps a strategic comma would serve, to clearly describe the sack as two failures, both of which are necessary to fit the definition, rather than one with two parts, either of which satisfies. And I guess I'm guilty of "unnatural interpretation", as I had no problem understanding the sentence as it was intended, due probably to context.

72
by dbostedo :: Tue, 04/29/2014 - 11:08am

Maybe I can help... What Rick is pointing out is that these 3 things are not the same :

A) "...a sack is simply a pass play where the quarterback failed to get rid of the ball and gain positive yardage."

B) "...a sack is simply a pass play where the quarterback failed to either get rid of the ball or gain positive yardage."

C) "...a sack is simply a pass play where the quarterback failed to get rid of the ball and failed to gain positive yardage."

A is the original, B and C are more properly correct. (Hopefully adding the "either" in B clarifies the issue with A, as writing "to either get rid of the ball and gain positive yardage" doesn't make sense.)

That said, I think a lot of people would understand your original statement the way you intended it. Common English semantics/grammar/context don't necessarily follow boolean logic.

55
by SandyRiver :: Mon, 04/28/2014 - 8:34am

from #46:
"For example, I just don't see Aaron Rodgers ever posting a 20 INT season, but the very low correlations listed would make this seem at least moderately likely. Another problem might be that year-to-year correlations ignore the fact that a QB with a very low career average interception percentage can show low year-to-year correlation, while still being objectively better at avoiding interceptions than another player with the same year-to-year correlation, but higher career percentage.
With the same year-to-year correlations, I know which QB I'd take."

Since I'm not so quick at stat analysis, I wonder which QB has the lower INT correlation, Eli (in 9 full seasons, avg 18.0, range 10 to 27) or Brady (last 9 full seasons, avg 10.7, range 4 to 14).

65
by Theo :: Mon, 04/28/2014 - 1:20pm

"reminding us why they play defense"

Tsk! Just remind yourself that every interception was a ball not intended for the guy who caught it.
You never hear, when an offensive player whiffs a tackle "that's why he plays offense"