Von Miller – FootballPerspective.com

Adjusting team sack rates in the NFL for SOS

Chase Stuart — Mon, 17 Dec 2012 04:01:59 +0000

I’ve got sacks on the mind today. A few hours ago, I looked at the single-season sack records by various players in both the 3-4 and 4-3. Today I also want to look at things from the team perspective. In 2012, which team is the best at getting to the quarterback? You might think that’s as simple as looking at a list of defensive statistics and sorting by sacks, but I’d like to take a more nuanced approach.

There are two factors that heavily impact a team’s sack rate: the opponents they face and the number of passing plays they defend. Using sack rate instead of sacks helps to solve the latter issue, but we still need an opponent adjustment even if we use sack rate. It’s a bit tricky doing it correctly, because you need to iterate the results just like you do with the SRS. What I mean by that is the sack rate of the Denver defense will need to be adjusted for the sack rate of the Kansas City, Oakland, and San Diego offenses (among other teams), and those will need to be adjusted for the Denver defense (and all the other defenses those teams faced).

Once you properly iterate the results, what are the results? The table below shows the top defenses this year at getting to the quarterback, although note that these numbers exclude the games from week 15. The table shows how many pass attempts each team has faced, the number of actual sacks they have recorded and their actual sack rate; the next column shows the SOS adjustment to the sack rate, with a positive number indicating a difficult strength of schedule (i.e., they’ve faced teams that are difficult to sack). The last two columns show the SOS-adjusted sack rates and total sacks.

Rk	Team	ATT	ACT SK	SK RT	SOS	ADJ SK RT	ADJ SK
1	DEN	506	39	7.7%	0.9%	8.6%	43.3
2	CIN	542	43	7.9%	0.5%	8.4%	45.7
3	ARI	426	34	8%	-0.5%	7.4%	31.7
4	DAL	429	29	6.8%	0.3%	7.1%	30.4
5	CAR	483	30	6.2%	0.9%	7.1%	34.2
6	KAN	389	24	6.2%	0.9%	7.1%	27.5
7	STL	489	39	8%	-1.2%	6.8%	33.1
8	PHI	467	28	6%	0.8%	6.8%	31.6
9	HOU	533	37	6.9%	-0.2%	6.7%	35.9
10	MIA	532	37	7%	-0.2%	6.7%	35.7
11	GNB	524	35	6.7%	-0.1%	6.6%	34.6
12	BAL	506	30	5.9%	0.6%	6.6%	33.3
13	CLE	531	34	6.4%	0.2%	6.6%	34.8
14	NYG	464	31	6.7%	-0.1%	6.5%	30.4
15	SFO	478	32	6.7%	-0.4%	6.3%	30.3
16	PIT	434	26	6%	0.3%	6.3%	27.4
17	ATL	463	28	6%	0.3%	6.3%	29.2
18	BUF	484	31	6.4%	-0.2%	6.2%	30.2
19	CHI	498	33	6.6%	-0.5%	6.1%	30.6
20	SDG	508	25	4.9%	1%	5.9%	30
21	TEN	481	27	5.6%	0.3%	5.9%	28.3
22	SEA	475	32	6.7%	-1.1%	5.7%	27
23	NWE	511	28	5.5%	-0.1%	5.3%	27.3
24	NOR	496	25	5%	0.2%	5.3%	26.1
25	MIN	515	31	6%	-0.8%	5.2%	27
26	DET	490	30	6.1%	-1.1%	5%	24.4
27	WAS	539	23	4.3%	0.7%	4.9%	26.6
28	TAM	541	24	4.4%	0.5%	4.9%	26.5
29	NYJ	446	22	4.9%	-0.1%	4.8%	21.5
30	IND	470	24	5.1%	-0.4%	4.7%	22.3
31	OAK	465	17	3.7%	0.7%	4.3%	20.1
32	JAX	464	14	3%	0%	3%	14

Miller had two sacks against Brady.

Let’s go through a couple of examples.

The Rams actually lead the league in sack rate, although I doubt many people would have guessed that so it’s hard to call them overrated. We’ll get to the offensive sack rates in a minute, but the key here is that the 49ers and Cardinals rank last in offensive sack rate (after adjusting for SOS). So four of the Rams 13 games came against the two easiest teams to sack, and the 29th and 30th easiest teams to sack — Green Bay and Chicago — were also on the St. Louis schedule. St. Louis has 39 sacks this year, but 24 of them came in those six games. The Rams produced a 9.6% sack rate against those teams and a 6.3% rate in their other games. St. Louis is far from a fraud, but they’re more accurately rated as the 7th best pass rushing team, not the first.

In the AFC West, the Chargers and Broncos are underrated because of their difficult schedules. That might surprise you, but consider that the AFC West played the NFC South, which featured New Orleans, Tampa Bay, and Atlanta, three teams that rank in the top quarter of the league in offensive adjusted sack rate. Oakland and Denver also rank in the top eight, giving San Diego’s defense two more difficult games, while Denver had two games against the Raiders along with a game against the always-difficult-to-sack Patriots. Cleveland and Pittsburgh also rank as harder than average to sack, and more importantly, there were few patsies on the schedules of either Denver of Oakland. Denver already ranked 4th in sack rate, but once you adjust for SOS, they move ahead of the two NFC West teams and Cincinnati and rank first in the league.

What about the offenses?

Rk	Team	ATT	ACT SK	SK RT	SOS	ADJ SK RT	ADJ SK
1	NYG	479	15	3.1%	0.1%	3%	14.4
2	NWE	519	20	3.9%	0.1%	3.7%	19.5
3	DEN	503	19	3.8%	-0.2%	4%	19.9
4	NOR	559	23	4.1%	0.1%	4%	22.6
5	HOU	471	17	3.6%	-0.5%	4.1%	19.2
6	TAM	442	19	4.3%	0.1%	4.2%	18.4
7	OAK	561	26	4.6%	0.3%	4.4%	24.4
8	ATL	535	24	4.5%	0.1%	4.4%	23.7
9	DET	618	26	4.2%	-0.3%	4.5%	27.6
10	CLE	487	24	4.9%	0.4%	4.6%	22.2
11	PIT	510	27	5.3%	0.2%	5.1%	25.9
12	DAL	567	31	5.5%	0.2%	5.3%	29.9
13	TEN	499	26	5.2%	-0.5%	5.7%	28.6
14	BUF	432	25	5.8%	-0.3%	6.1%	26.2
15	IND	569	32	5.6%	-0.6%	6.2%	35.5
16	BAL	482	31	6.4%	0.2%	6.3%	30.3
17	MIA	442	27	6.1%	-0.2%	6.3%	27.8
18	SEA	365	24	6.6%	0.2%	6.4%	23.4
19	STL	464	31	6.7%	-0.1%	6.8%	31.5
20	KAN	437	31	7.1%	0.2%	6.9%	30.1
21	SDG	503	37	7.4%	0.4%	6.9%	34.9
22	WAS	392	29	7.4%	0.3%	7.1%	27.7
23	PHI	575	42	7.3%	0.2%	7.1%	41
24	MIN	429	28	6.5%	-0.7%	7.3%	31.2
25	CAR	425	31	7.3%	0%	7.3%	31.1
26	NYJ	435	31	7.1%	-0.2%	7.3%	32
27	CIN	512	38	7.4%	0%	7.4%	37.8
28	JAX	500	40	8%	-0.3%	8.3%	41.5
29	CHI	444	37	8.3%	-0.4%	8.7%	38.7
30	GNB	484	42	8.7%	-0.5%	9.2%	44.3
31	ARI	555	51	9.2%	-0.1%	9.2%	51.3
32	SFO	384	38	9.9%	-0.1%	10%	38.3

The Giants lead the NFL in sack rate and adjusted sack rate. The Broncos are the king of the statistic on both sides of the ball, ranking 1st on defense and third on offense. There’s a reason Denver is likely going to enter the playoffs on an 11-game winning streak. Having Von Miller and Peyton Manning helps quite a bit, although check out this article on how Elvis Dumervil is playing a key role for the Broncos this year. In general, SOS matters a bit more when looking at the best pass rushing teams than at the best pass blocking teams (or teams with the best quarterback). This could be an indication that in a given game, the sack rate for each team is more a function of the offense than the defense. I’ve never really looked into that, and that’s a worthy subject for another post. But the key here is that the adjustments simply aren’t that significant.

Philip Rivers and the Chargers rank 26th in unadjusted sack rate, but after adjusting for strength of schedule — two games against the Broncos, a game against Cincinnati, and six more games against better than average pass-rushing teams — they move up to 21st. Von Miller alone had four sacks in two games against San Diego.

What teams move down? The Minnesota Vikings have had a really cushy slate of opposing defenses, which makes Christian Ponder’s struggles even more perplexing. The Vikings played the Jaguars (#32 in sack rate), Colts (30), Buccaneers (28), Redskins (27) and faced the Lions (26) twice, and were sacked 17 times in those six games. In their only game against a top-pass rushing defense, the Cardinals had 3 sacks on just 20 Vikings dropbacks.

I’m going to end with a bunch of disclaimers that are important to keep in mind here. The sack is one of the most misleading statistics in the NFL, especially when looking at individual players. A pass rusher can make a difference on plays by rushing the quarterback and forcing an errant throw (or a sack by a teammate), or by hitting the quarterback on a play. A pass rusher can force a sack by tying up blockers and allowing his teammates to get to the quarterback to record a sack or force an errant throw. When the difference between a great pass rusher is roughly one extra sack per 50 throws, well, “sacks” as a metric simply don’t give us a lot of information.

Also, I suspect there’s a correlation between Game Scripts and sacks per attempt. That’s a complicated issue to resolve, but teams that play with big leads are likely going to get more sacks per opponent pass attempt than teams that are trailing. Perhaps even more importantly, not all passing plays are the same. Football Outsiders calculates an adjusted sack rate which not only adjusts for SOS but for the type of pass play (e.g., it is easier to record a sack on third and long than on second and short) that I highly recommend.

J.J. Watt breaks sack record — for 3-4 defensive linemen

Chase Stuart — Mon, 17 Dec 2012 01:50:42 +0000

J.J. Swatt.

Houston’s J.J. Watt sacked Andrew Luck three times on Sunday, bringing his season sack total to 19.5. Entering 2012, Bruce Smith was the single-season record holder for sacks by a defensive lineman in a 3-4 scheme with 19 in 1990. The sack has only been an official statistic since 1982, but since the 3-4 only entered the NFL in the mid-’70s, we can be pretty sure that Watt is now the all-time record holder.

The tables below show the single-season leaders by various defensive players in 3-4 and 4-3 schemes from 1982 to 2011.

Let’s start with a look at the most sacks by a 3-4 defensive end:

Year	Team	Name	Pos	Sacks
1990	BUF	Bruce Smith	3-4 DE	19
1983	SFO	Fred Dean	3-4 DE	17.5
1984	PHI	Greg Brown	3-4 DE	16
1983	MIA	Doug Betters	3-4 DE	16
1983	SEA	Jacob Green	3-4 DE	16
1992	NOR	Wayne Martin	3-4 DE	15.5
1986	RAI	Sean Jones	3-4 DE	15.5
1985	NYG	Leonard Marshall	3-4 DE	15.5
1993	KAN	Neil Smith	3-4 DE	15
1986	SDG	Lee Williams	3-4 DE	15
1986	BUF	Bruce Smith	3-4 DE	15
1984	KAN	Art Still	3-4 DE	14.5
1984	SEA	Jeff Bryant	3-4 DE	14.5
1983	GNB	Ezra Johnson	3-4 DE	14.5
1997	BUF	Bruce Smith	3-4 DE	14
1993	BUF	Bruce Smith	3-4 DE	14
1992	BUF	Bruce Smith	3-4 DE	14
1989	SDG	Lee Williams	3-4 DE	14
1984	MIA	Doug Betters	3-4 DE	14
1984	CLE	Reggie Camp	3-4 DE	14
1983	PIT	Keith Willis	3-4 DE	14

As you can imagine, 3-4 defensive linemen don’t rack up many sacks. Bill Pickel, a nose tackle for the Raiders in the ’80s, recorded 12.5 sacks in both ’84 and ’85, making him the only 3-4 tackle to record more than 12 sacks in a season. Karl Mecklenburg, with 13 sacks for the Broncos in ’85, remains the only inside linebacker in a 3-4 with more than a dozen sacks.

Of course, 3-4 outside linebackers get all the glory in that scheme. San Francisco’s Aldon Smith has 19.5 sacks so far in 2012 with two games remaining, but here were the leaders prior to 2012:

Year	Team	Name	Pos	Sacks
1986	NYG	Lawrence Taylor	3-4 OLB	20.5
2008	DAL	DeMarcus Ware	3-4 OLB	20
1990	KAN	Derrick Thomas	3-4 OLB	20
2011	DAL	DeMarcus Ware	3-4 OLB	19.5
1989	GNB	Tim Harris	3-4 OLB	19.5
1984	NWE	Andre Tippett	3-4 OLB	18.5
2008	MIA	Joey Porter	3-4 OLB	17.5
1995	BUF	Bryce Paup	3-4 OLB	17.5
2009	DEN	Elvis Dumervil	3-4 OLB	17
2006	SDG	Shawne Merriman	3-4 OLB	17
1992	SFO	Tim Harris	3-4 OLB	17
1991	NOR	Pat Swilling	3-4 OLB	17
1989	NOR	Pat Swilling	3-4 OLB	16.5
1989	RAM	Kevin Greene	3-4 OLB	16.5
1988	RAM	Kevin Greene	3-4 OLB	16.5
1985	NWE	Andre Tippett	3-4 OLB	16.5
2008	PIT	James Harrison	3-4 OLB	16
1992	DEN	Simon Fletcher	3-4 OLB	16
1990	SFO	Charles Haley	3-4 OLB	16
2010	DAL	DeMarcus Ware	3-4 OLB	15.5
1988	NYG	Lawrence Taylor	3-4 OLB	15.5
1998	CAR	Kevin Greene	3-4 OLB	15
1989	NYG	Lawrence Taylor	3-4 OLB	15
1984	PIT	Mike Merriweather	3-4 OLB	15

What about 4-3 defensive ends?

Year	Team	Name	Pos	Sacks
2001	NYG	Michael Strahan	4-3 DE	22.5
2011	MIN	Jared Allen	4-3 DE	22
1984	NYJ	Mark Gastineau	4-3 DE	22
1989	MIN	Chris Doleman	4-3 DE	21
1987	PHI	Reggie White	4-3 DE	21
1992	PHI	Clyde Simmons	4-3 DE	19
1983	NYJ	Mark Gastineau	4-3 DE	19
2003	NYG	Michael Strahan	4-3 DE	18.5
2002	MIA	Jason Taylor	4-3 DE	18.5
1986	WAS	Dexter Manley	4-3 DE	18.5
2011	PHI	Jason Babin	4-3 DE	18
1988	PHI	Reggie White	4-3 DE	18
1984	CHI	Richard Dent	4-3 DE	17.5
1999	STL	Kevin Carter	4-3 DE	17
1992	SDG	Leslie O'Neal	4-3 DE	17
1985	CHI	Richard Dent	4-3 DE	17
2011	NYG	Jason Pierre-Paul	4-3 DE	16.5
2008	ATL	John Abraham	4-3 DE	16.5
2000	MIA	Trace Armstrong	4-3 DE	16.5
1999	ARI	Simeon Rice	4-3 DE	16.5
1998	SEA	Michael Sinclair	4-3 DE	16.5
2005	OAK	Derrick Burgess	4-3 DE	16
2004	IND	Dwight Freeney	4-3 DE	16
1998	GNB	Reggie White	4-3 DE	16
1983	STL	Curtis Greer	4-3 DE	16

And 4-3 defensive tackles:

Year	Team	Name	Pos	Sacks
1989	MIN	Keith Millard	4-3 DT	18
1986	PHI	Reggie White	4-3 DT	18
2000	NOR	La'Roi Glover	4-3 DT	17
2000	TAM	Warren Sapp	4-3 DT	16.5
1997	MIN	John Randle	4-3 DT	15.5
1997	SFO	Dana Stubblefield	4-3 DT	15
1992	SEA	Cortez Kennedy	4-3 DT	14

4-3 outside linebackers rarely rack up huge sack numbers. In fact, Denver’s Von Miller, who has 16 sacks this year, is already the record holder in the official sack era. Derrick Thomas (14.5 sacks in 1992, 13 in 1996) in Kansas City, Washington’s Ken Harvey (13.5 in ’94) and Cleveland’s Jamir Miller (13 in ’01) are the only other 4-3 outside linebackers with more than twelve sacks in a season since 1982. (Of course, Thomas also had a 20-sack season a 3-4 outside linebacker.) Charlie Clemons, with 13.5 sacks in 2001, is the record holder among 4-3 middle linebackers.