Defensive Smackdown

Rich Schultz

How good have Rex Ryan's defenses really been?

The statistic Rex Ryan and many Jets fans like to look to in measuring the effectiveness of Jets defenses during Ryan's tenure is total yards allowed.  Under that metric the Ryan defenses have been very good, though declining every year of Ryan's reign.  In 2009 the Jets defense was indisputably the best defense in the NFL.  It was #1 in yards allowed, #1 in points allowed, #1 against the pass.  That was a truly dominant defense.  In every year since, however, the defense has regressed in terms of total yards allowed.  From #1 in 2009, the defense has trended ever lower, to #3 in 2010, #5 in 2011, #8 in 2012 and finally #11 in 2013.   That is not the best of all possible trend lines, but it still reflects a pretty good defense even at its worst.


However, there is more to defense than just not allowing yards.  After all, the team that allows the fewer yards is not declared the winner after 60 minutes of play.   It's points that count, right?  In this metric Ryan's defenses have not fared nearly as well.  From #1 in 2009 the Jets defense rapidly diminished, to #6 in 2010, #20 in 2011, #20 in 2012, and #19 in 2013.  Ugh.  That progression is downright ugly.  But is it a better, more accurate reflection of the Jets' defensive prowess?  I would argue it is not, for one simple reason: turnovers.  Specifically, the Jets have turned the football over at an alarming rate in every year other than 2010 of the Rex era.  Teams with offenses that constantly hand the ball to the defense are obviously going to give up more points than teams that rarely turn the ball over, all other things being equal.  So even though at a very basic level one could argue that all that matters is points allowed, if you really want to get at which teams have the best defenses it would seem necessary to account for how often the offense turns the ball over.


This conundrum might sway you to revert back to yards allowed as the best measure of a defense, since yards allowed is in theory solely affected by defensive prowess, without being distorted by the effects of offensive turnovers. But is there a better way?  After all, it is certainly possible to envision a defense that gives up chunks of yardage between the 20s while doing two things well: creating turnovers and keeping the opposing team out of the end zone.  This in fact is pretty much what a typical Tampa 2 defense is designed to do.  If effective, such a defense could conceivably be the best defense in football without necessarily ranking all that high in terms of yards allowed.  So, how do we get a better measure of defensive prowess, one that not only takes into account the most important factor of all, points allowed, but also accounts for differing levels of difficulty based on how often the offense turns the ball over, thus increasing the odds of the defense giving up points for reasons that are all about the ineptitude of the offense, not the effectiveness of the defense?



Such a metric would have to solve this important puzzle: how many points is a turnover worth?  If we can quantify how much damage an offensive turnover does to defensive points allowed, then we can devise an "adjusted points allowed" metric which would in theory roughly project how many points every defense "should have" allowed, had every offense committed zero turnovers.  By placing every defense on a level playing field in this theoretical zero offensive turnover universe, we can in theory rank each team's true effectiveness in preventing opposing teams from scoring.  This system would have the virtue of largely eliminating the unfortunate distortions caused by offensive turnovers of ranking defenses by the simpler points allowed method.  It would also have the virtue of eliminating the distortions caused by ranking defenses with wildly divergent defensive philosophies by yards, where a system that is designed to give up yards but not points is unfairly penalized in comparison to a defense that may give up few yards but is inefficient at preventing points.  Finally this new metric would indirectly account for the increased defensive prowess of defenses that generate bunches of turnovers, in that the adjusted points allowed metric is a scoring metric, not a yards metric.  As such this metric will reward defenses that may give up a few more yards but are in fact more effective because they generate lots of turnovers and thereby prevent the opposition from  scoring.



This brings us to the all important question for the purposes of this new metric: how many points is a turnover worth?  If we can't answer this question with a reasonable degree of accuracy then the whole exercise is doomed.  Fortunately for us, there have been several studies that have done fairly sophisticated statistical analysis of this question, and have come up with a fairly consistent answer.  It turns out a turnover is worth just about 4 points.  Some studies place that number slightly higher, some slightly lower, but all come up with close to that same 4 point answer.  How very fortunate for us the math nerds have answered this all important question.  If you're interested in the details of how the mathematicians have answered this question, I refer you to the excellent articles found at Football OutsidersSportsRatings, and Sportsquant which detail some of the analysis that went into this answer.  Armed with this information we can proceed to build a metric which should be better than either points allowed or yards allowed in measuring the effectiveness of NFL defenses.

Here's how we build our model.  First we rank all NFL teams by points allowed, since the bottom line in the NFL is points.  Then, for every time each NFL team's offense turned the ball over, we subtract 4 points from the defense's points allowed total.  This simple calculation will in theory remove distortions caused by the offensive turnovers of each team and project just the points the defense should be held accountable for if all offenses had been turnover free.  In effect it levels the playing field for the defenses, and we are left with what should be something approximating a "pure" measure of defensive prowess, free from the distortions of offensive turnovers.  Since I have never seen this metric used anywhere before, unless somebody can point me to a prior author, I get to name this metric.  Yay!  Let's call this metric the Defensive Smackdown ratings.  These ratings should be better than either yards allowed or points allowed in measuring the effectiveness of NFL defenses.  So, without further verbosity, I present the Defensive Smackdown ratings for all NFL defenses during the Rex era.

<

2013
Team Points Allowed Offensive Turnovers Virtual Turnover Points Adjusted Points Allowed Rank
SEA 231 19 76 155 1
CAR 241 19 76 165 2
CIN 305 30 120 185 3
ARI 324 31 124 200 4
NYG 383 44 176 207 5
SF 273 16 64 209 6
NO 304 19 76 228 7
MIA 335 26 104 231 8
KC 305 18 72 233 9
BAL 352 29 116 236 10
DET 376 34 136 240 11
NE 338 20 80 258 12
SD 348 21 84 264 13
NYJ 387 29 116 271 14
PIT 370 24 96 274 15
BUF 388 27 108 280 16
IND 336 14 56 280 16
STL 364 21 84 280 16
TEN 381 25 100 281 19
CLE 406 29 116 290 20
DEN 399 26 104 295 21
HOU 428 31 124 304 22
TB 389 21 84 305 23
PHI 382 19 76 306 24
WAS 388 14 56 326 25
GB 428 25 100 328 26
ATL 443 28 112 331 27
OAK 453 31 124 331 27
JAX 449 27 108 341 29
DAL 432 20 80 352 30
MIN 480 32 128 352 30
CHI 478 23 92 386 32

Jets

<

2012
Team Points Allowed Offensive Turnovers Virtual Turnover Points Adjusted Points Allowed Rank
SEA 245 18 72 173 1
CHI 277 24 96 181 2
DEN 289 25 100 189 3
PIT 314 30 120 194 4
SF 273 16 64 209 5
MIA 317 26 104 213 6
CIN 320 26 104 216 7
ARI 357 34 136 221 8
ATL 299 18 72 227 9
NYJ 375 37 148 227 9
SD 350 26 104 246 11
MIN 348 23 92 256 12
NYG 344 21 84 260 13
HOU 331 17 68 263 14
CLE 368 26 104 264 15
STL 348 22 84 264 15
NE 331 16 64 267 17
GB 336 16 64 272 18
CAR 363 22 88 275 19
KC 425 37 148 277 20
IND 387 27 108 279 21
BAL 344 16 64 280 22
DAL 400 29 116 284 23
BUF 435 34 136 299 24
TB 394 23 92 302 25
DET 437 33 132 305 26
PHI 382 19 76 306 27
WAS 388 14 56 332 28
OAK 443 26 104 339 29
JAX 444 26 104 340 30
NO 454 24 96 358 31
TEN 471 28 112 359 32

<

2011
Team Points Allowed Offensive Turnovers Virtual Turnover Points Adjusted Points Allowed Rank
PIT 227 28 112 115 1
PHI 328 38 152 176 2
SF 229 10 40 189 3
HOU 278 20 80 198 4
MIA 313 25 100 213 5
ARI 348 32 128 220 6
SEA 315 23 92 223 7
CHI 341 29 116 225 8
KC 338 28 112 226 9
NYJ 363 34 136 227 10
WAS 367 35 140 227 10
TEN 317 22 88 229 12
CLE 307 19 76 231 13
CIN 323 22 88 235 14
JAX 329 23 92 237 15
DAL 347 21 84 263 16
NO 339 19 76 263 16
ATL 350 21 84 266 18
DEN 390 30 120 270 19
NE 342 17 68 274 20
BAL 378 24 96 282 21
SD 406 28 112 294 22
DET 387 23 92 295 23
GB 359 14 56 303 24
NYG 400 24 96 304 25
OAK 433 30 120 313 26
BUF 434 30 120 314 27
IND 430 29 116 314 27
STL 407 23 92 315 29
TB 494 40 160 334 30
CAR 429 23 92 337 31
MIN 449 26 104 345 32

<

2010
Team Points Allowed Offensive Turnovers Virtual Turnover Points Adjusted Points Allowed Rank
GB 240 22 88 152 1
PIT 232 18 72 160 2
CHI 286 31 124 162 3
NYG 347 42 168 179 4
NO 307 31 124 183 5
BAL 270 20 80 190 6
MIN 348 37 148 200 7
SD 322 29 116 206 8
MIA 333 31 124 209 9
CLE 332 29 116 216 10
NYJ 304 21 84 220 11
ATL 288 17 68 220 11
TEN 339 29 116 223 13
TB 318 19 76 242 14
STL 328 21 84 244 15
WAS 377 31 124 253 16
SF 346 23 92 254 17
CIN 395 34 136 259 18
CAR 408 37 148 260 19
OAK 371 26 104 267 20
DET 369 25 100 269 21
BUF 425 39 156 269 21
KC 326 14 56 270 23
NE 313 10 40 273 24
PHI 377 25 100 277 25
SEA 407 31 124 283 26
JAX 419 33 132 287 27
IND 388 25 100 288 28
ARI 434 35 140 294 29
DAL 436 30 120 316 30
HOU 427 18 72 355 31
DEN 471 27 108 363 32

<

2009
Team Points Allowed Offensive Turnovers Virtual Turnover Points Adjusted Points Allowed Rank
NYJ 236 30 120 116 1
BAL 261 22 88 173 2
DAL 250 19 76 174 3
ARI 325 36 144 181 4
CAR 308 31 124 184 5
SF 281 24 96 185 6
CIN 291 25 100 191 7
NE 285 22 88 197 8
BUF 326 30 120 206 9
IND 307 24 96 211 10
HOU 333 28 112 221 11
PIT 324 25 100 224 12
WAS 336 28 112 224 12
ATL 325 25 100 225 14
NO 341 28 112 229 15
CHI 375 36 144 231 16
GB 297 16 64 233 17
DEN 326 23 92 234 18
MIN 312 18 72 240 19
PHI 337 23 92 245 20
OAK 379 33 132 247 21
CLE 375 31 124 251 22
SD 320 17 68 252 23
TB 400 34 136 264 24
SEA 390 31 124 266 25
MIA 390 29 116 274 26
TEN 402 31 124 278 27
JAX 380 23 92 288 28
NYG 427 31 124 303 29
STL 436 33 132 304 30
KC 424 27 108 316 31
DET 494 41 164 330 32

There are a few things of note here.  First, it is interesting that according to the Defensive Smackdown ratings, the Jets defense has been good but not really elite in any year since 2009.  In fact the Jets defense, despite a near complete overhaul in personnel, has been surprisingly consistent in its ranking.  From 2010 through 2013 the Jets defense ranked #11, #10, #9 and #14.  For Rex detractors these numbers can be used to perhaps show how after the Jets overload blitzes took the league by storm in 2009, the league quickly caught up and the vaunted Rex defense has been just a little better than average ever since.  On the other hand Rex supporters also can draw something from these numbers, as the Jets defense is the only defense in the entire NFL to never rank in the bottom half of the league over the last five years.

Interestingly the Jets defense in 2013, despite being repeatedly burned deep, would likely have come in at just about the same level as the prior three years if it had only been able to generate turnovers at closer to a league average rate.  As it was the Jets were the second worst team in generating turnovers, and although these charts do not capture the net effect of that deficit, it is not difficult to see how the Jets lack of defensive turnovers would have led to more points for opposing offenses.

It may also be interesting to note that since 2009 the Jets defense has not even been the best in the AFC East, ceding that title to the Miami Dolphins every year since, and in 2013 even the lowly Patriots had a better defense than the Jets.  A big part of that picture is the Jets inability to generate a consistent pass rush since 2009 and a decreasing ability to generate turnovers, particularly since Revis left town.  GGN's own Xes&Os wrote a series of insightful fanposts regarding the Jets defense, the pass rush, and turnovers last year which may provide significant insight into these issues. You can check these out here:  Wrong Kind of Defense?, Rex's Pass RushNo Turnovers, Ryan Blitzes.

How about you?  Do you think the Defensive Smackdown ratings present an accurate picture of the Jets defense over the years?  What do you see in the numbers and on the field?  Is there something the Jets should be doing differently?  Do you expect to see major improvements in any areas in 2014 and beyond?  Will the Jets ever return to defensive dominance?   Let us know your thoughts in the comments.

X
Log In Sign Up

forgot?
Log In Sign Up

Forgot password?

We'll email you a reset link.

If you signed up using a 3rd party account like Facebook or Twitter, please login with it instead.

Forgot password?

Try another email?

Almost done,

By becoming a registered user, you are also agreeing to our Terms and confirming that you have read our Privacy Policy.

Join Gang Green Nation

You must be a member of Gang Green Nation to participate.

We have our own Community Guidelines at Gang Green Nation. You should read them.

Join Gang Green Nation

You must be a member of Gang Green Nation to participate.

We have our own Community Guidelines at Gang Green Nation. You should read them.

Spinner.vc97ec6e

Authenticating

Great!

Choose an available username to complete sign up.

In order to provide our users with a better overall experience, we ask for more information from Facebook when using it to login so that we can learn more about our audience and provide you with the best possible experience. We do not store specific user data and the sharing of it is not required to login with Facebook.

tracking_pixel_9341_tracker