by Vincent Verhei

If you're reading this, odds are good that you've got some familiarity with football statistics -- which numbers are relevant and meaningful, and which are more trivial and insignificant. Take quarterback stats, for example. Tune in to your average highlight show or sports radio station and you'll no doubt hear how many passing yards your local signal-caller accumulated after each game. Fantasy players will want that info, but will want to know how many touchdowns their guy had too. Old-school coaches will mostly focus on how many interceptions he threw. Those seeking deeper analysis will look at completion percentage, yards per pass, or even NFL passer rating. Others will turn to adjusted net yards per attempt at Pro Football Reference, which is often more accurate than any of these because it also includes data on sacks. Here are at Football Outsiders, of course, we prefer DVOA, and that's partly because it includes very important information that is not available in any of these other numbers. Because in 2017, there is something more important than yards, touchdowns, sacks, or interceptions when evaluating quarterbacks. This year, the most critical element in evaluating a quarterback's performance might be the quality of the defense on the other side of the ball.

We have been doing opponent adjustments for quarterbacks (and other players) since Day 1 around here, but we have never seen them have such dramatic effects as they're having this year. This is what happens when you have a defense like Jacksonville, which already has 11 interceptions and 35 sacks -- more than several teams had in all of 2016. At the same time, you have to account for a defense like Oakland, the first team since at least 1940 to get through its first nine games without intercepting a single pass. Those aren't the only teams with extreme results either. The wild disparity in pass defenses this year is having a massive effect on quarterback adjustments.

We can use some pretty standard mathematical evaluations to show the gaps between the best and worst pass defenses this year. The variance of all 32 pass defense DVOAs in 2017 is 4.1 percent; the highest we have on record for a full season since 1986 was 3.6 percent in 1991. If you prefer to measure these numbers in standard deviations, then you get 20.0 percent for this season, and 18.9 percent for 1991. That shows how radical the differences between the best and worst pass defenses are this year, but it still doesn't tell us the full picture. Is it the elite defenses that are skewing these results, the terrible defenses, or both?

Let's take a more detailed look at what's going on this season. Jacksonville, of course, has the best pass defense DVOA in the league at -35.2%. The average of the best pass defense DVOA each season from 2002 to 2016 was -29.1%. So Jacksonville isn't just the best pass defense this season, but they're about 6.0% better (accounting for rounding errors) than the best pass defense in a typical season. This year's second-best pass defense, the Rams, has a DVOA of-24.5% -- 5.1% better than the average of -19.4% for the second-best defenses of the past 15 years. Oakland, meanwhile, has a pass defense DVOA of 49.3% -- that is 17.4% worse than the usual league-worst pass defense of 31.9%. (We went back to 2002 because that was the year the NFL expanded to 32 teams. We also checked the numbers for the top 10 and bottom 10 teams each season since 1986, but the results were very similar.)

The following table shows where each team ranks in pass defense DVOA this season (not including the Miami-Carolina Monday night game), and what we would expect their DVOA to be based on historical norms of teams ranked in that slot.

2017 Pass Defense DVOA vs. Historical Norms Rank Team DVOA Normal

DVOA* Dif

Rank Team DVOA Normal

DVOA* Dif 1 JAC -35.2% -29.1% -6.0% 17 DEN 9.3% 5.6% 3.7% 2 LARM -24.5% -19.4% -5.1% 18 ARI 9.6% 7.5% 2.1% 3 BAL -23.0% -16.7% -6.3% 19 DAL 12.5% 8.3% 4.2% 4 NO -20.8% -13.1% -7.7% 20 ATL 14.1% 9.1% 5.0% 5 PIT -11.2% -10.8% -0.4% 21 NYJ 15.2% 9.7% 5.5% 6 CAR -8.6% -9.3% 0.7% 22 KC 15.2% 10.8% 4.4% 7 LACH -5.8% -7.7% 1.9% 23 GB 21.5% 12.1% 9.4% 8 SEA -5.7% -6.4% 0.7% 24 TEN 22.4% 12.8% 9.6% 9 PHI -3.9% -4.4% 0.5% 25 IND 27.4% 14.4% 13.0% 10 DET -2.5% -2.9% 0.3% 26 CLE 27.7% 16.4% 11.4% 11 CHI -1.2% -1.3% 0.1% 27 SF 28.0% 18.0% 10.0% 12 MIN -0.5% 0.0% -0.5% 28 TB 31.7% 20.1% 11.6% 13 BUF 2.2% 1.2% 1.0% 29 NYG 32.8% 22.9% 9.9% 14 WAS 2.6% 2.4% 0.1% 30 NE 34.1% 25.5% 8.6% 15 CIN 4.1% 3.1% 1.0% 31 MIA 36.9% 27.4% 9.6% 16 HOU 6.9% 4.8% 2.1% 32 OAK 49.3% 31.9% 17.4% * Average Pass Defense DVOA at this Ranking, 2002-2016

This makes the strength of the best pass defenses this year very clear. We already mentioned that Jacksonville and the Rams are significantly better than the best two pass defenses in most years, but Baltimore is also better than the typical third-place team, while the Saints (Really! We double-checked!) are better than what you would expect from a fourth-place team. That's four teams with a pass defense DVOA of -20.0% or better, which would tie the record (set in 1990 and 2008) for most such defenses in a season, assuming each can maintain that level of performance over the next seven weeks.

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After that, things start to level off, and the next dozen or so teams fall about where you would expect them to. Around the halfway point, though, things head south in a hurry. The bad pass defenses this year are all worse than they would be in a typical season, and those at the bottom end of the table are especially putrid. There are 10 teams this year with pass defense DVOAs of 20.0% or higher. That would shatter the record of seven, set in 2004, 2013, and 2015. The Raiders are threatening to break the all-time record for worst pass defense DVOA, the 48.1% mark set by the Saints way back in 2015.

With so many good defenses this year -- and so many, many bad defenses -- the schedule strength for quarterbacks should tend to even out over the course of the season. Every quarterback is going to bump into these teams a lot. After 10 weeks, Ben Roethlisberger's passing DYAR gets a +193 boost in DYAR after opponent adjustments, the highest in the league, while Philip Rivers has the highest penalty at -141 DYAR. Both have a long way to go before we worry about the records of +372 set by Tom Brady in 2009, or -291 set by Kurt Warner in 1999. (Bizarre fact: Matt Ryan is in second place in both categories, with a +300 in 2013 and a -280 in 2015.) It's also possible that some of these extremes will level off over the rest of the year, and opponent adjustments won't be as strong then as they are now.

In the small picture, though, it's crucial that we keep defenses in mind when we are evaluating quarterbacks each week. With all the hype around the quarterback position this year, some might believe that defense doesn't matter anymore, but nothing could be further from the truth. In some ways, defense matters more than it has in a long, long time.

Quarterbacks Rk Player Team CP/AT Yds TD INT Sacks Total

DYAR Pass

DYAR Rush

DYAR Opp 1. Cam Newton CAR 21/35 254 4 0 0 160 129 31 MIA 2. Philip Rivers LACH 21/37 235 2 1 0 159 159 0 JAC Rivers is the first quarterback to throw two touchdown passes against Jacksonville this year, and also the first quarterback to play the Jaguars and not give up a sack. He is just the second quarterback to throw for 235 yards against Jacksonville; the other was Ben Roethlisberger, whose 312 yards were accompanied by five interceptions. That is why he finished as the top quarterback on Sunday despite some pretty ugly splits. On third downs, he went 4-of-11 for 46 yards with only two conversions (including a touchdown) and one interception. This was a bizarre game in which the Chargers had many opportunities to kill clock and failed. On Los Angeles' final five drives (not including a kneeldown), Rivers went 1-of-4 with as many yards (1) as interceptions. 3. Tom Brady NE 25/34 266 3 0 1 145 149 -4 DEN No, it is not your imagination: Brady spent almost the entire game in Denver territory. New England's field position was so good, Brady only threw eight passes on the Patriots' side of the 50. (It helps that those eight throws resulted in six first downs and 96 total yards.) He was especially effective throwing to his backs: 7-of-7 for 44 yards and five first downs, including a pair of scores. An eighth throw resulted in a 3-yard DPI. 4. Case Keenum MIN 21/29 304 4 2 0 137 144 -6 WAS In one ten-pass stretch that started in the second quarter and ended in the third, Keenum completed nine passes for 137 yards and four touchdowns. Eight of those completions picked up first downs; the other was a 9-yard gain on first-and-10. Later, he threw interceptions on back-to-back plays. Streaks can run both ways. 5. Drew Stanton ARI 24/47 273 1 0 2 119 122 -3 SEA Stanton gets a big boost in opponent adjustments for throwing a zillion passes against a good defense. Before Richard Sherman's injury, Stanton went 8-of-17 (47%) for 89 yards (5.2-yard average) After Sherman's injury, including his last play, Stanton went 16-of-30 (53%) for 184 yards (6.1-yard average). 6. Jared Goff LARM 26/37 355 3 0 3 114 110 5 HOU Goff was terrific going up the middle against Houston: 7-of-8 for 162 yards. Yes, 94 of those yards came on one touchdown to Robert Woods, but only one of those completions (an 8-yard gain on third-and-15) was considered a failed play. 7. C.J. Beathard SF 19/25 288 2 1 0 100 80 19 NYG When C.J. Beathard is ripping your defense apart with long bombs, you may have problems in your secondary. On passes that traveled more than 15 yards downfield, Beathard went 4-of-6 for 190 yards and two touchdowns. 8. Matt Ryan ATL 22/29 215 2 1 1 98 98 0 DAL Ryan's first third-down pass against Dallas was intercepted, but he was nearly perfect after that: 8-of-9 for 100 yards with seven conversions (including a touchdown) and one sack. 9. Brett Hundley GB 18/25 212 1 0 3 92 83 9 CHI Hundley threw four passes to receivers 9 to 12 yards downfield; all were incomplete. His five passes deeper than that, though, resulted in four completions for 93 yards and a touchdown, plus a DPI for 29 more yards. 10. Drew Brees NO 18/25 184 0 0 0 71 61 10 BUF About three minutes into the third quarter, Brees completed a 21-yard pass to Michael Thomas on second-and-15. The Saints then proceeded to run the ball on 24 consecutive plays (including a Brees scramble for a touchdown), a stretch that covered four drives. Then Brees hit Thomas for 5 yards on a fourth-and-3, and the Saints ran the ball five more times to finish the game. On passes that traveled at least 5 yards past the line of scrimmage, Brees went 7-of-9 for 129 yards. 11. Jay Cutler MIA 22/37 213 2 1 0 70 70 0 CAR 12. Kirk Cousins WAS 26/45 327 1 1 1 68 51 17 MIN Aside from an interception, Cousins did very well moving Washington into scoring range. Once in scoring range, though, he had almost no success to speak of. Inside the Minnesota 30, he went just 1-of-11 with a sack. That one completion was a 7-yard gain on third-and-8. Rk Player Team CP/AT Yds TD INT Sacks Total

DYAR Pass

DYAR Rush

DYAR Opp 13. Nathan Peterman BUF 7/10 79 1 0 0 66 66 0 NO All of Peterman's plays came with Buffalo down by at least 37 points and less than five minutes to play. Six of his completions resulted in first downs; the other was a 9-yard gain on first-and-10. 14. Russell Wilson SEA 22/31 238 2 0 5 46 42 4 ARI The magic range for Wilson came 6 to 16 yards beyond the line of scrimmage. On passes at that distance, he went 8-of-10 for 138 yards and a touchdown. 15. Ryan Fitzpatrick TB 17/34 187 1 1 1 34 40 -6 NYJ Fitzpatrick didn't have much luck on deep passes against his old team: 2-of-8 for 39 yards with an interception. 16. Eli Manning NYG 28/37 273 2 0 3 30 30 0 SF Manning was really good in short-yardage against San Francisco -- not just at getting conversions, but in turning them into big plays. On third- or fourth-and-2, he went 5-of-6 for 87 yards. 17. DeShone Kizer CLE 21/37 232 1 1 1 25 12 13 DET Kizer struggled badly on third downs, going 3-of-8 for 19 yards and only one conversion. He did have more luck on fourth downs, going 3-of-3 for 45 yards and three conversions. The downside is that all three of those plays came with the Browns down by 14 points with less than four minutes to go. 18. Mitchell Trubisky CHI 21/35 297 1 0 5 22 22 0 GB Trubisky was at his best between the 40s: 8-of-11 for 138 yards and a touchdown. 19. Ben Roethlisberger PIT 19/31 236 2 1 1 20 25 -5 IND Roethlisberger's best range came 7 to 15 yards past the line of scrimmage, where he went 7-of-9 for 102 yards and two touchdowns. A tenth throw at that range resulted in an 11-yard DPI. 20. Jacoby Brissett IND 14/24 222 2 1 3 19 28 -10 PIT Brissett only went 3-of-8 on first downs, but he made those three completions count: a 16-yard gain to T.Y. Hilton, a 60-yard touchdown to Donte Moncrief, and a 61-yard touchdown to Chester Rogers. 21. Matthew Stafford DET 17/26 249 3 1 4 4 -6 10 CLE Stafford played well after halftime, but he was the worst first-half quarterback of the week: 6-of-11 for 57 yards with two sacks and an interception. Only one of those completions resulted in a first down. 22. Marcus Mariota TEN 25/44 264 1 1 4 0 -16 16 CIN Mariota really struggled to complete deep passes against the Bengals, going 1-of-8 for 20 yards. Rk Player Team CP/AT Yds TD INT Sacks Total

DYAR Pass

DYAR Rush

DYAR Opp 23. Blake Bortles JAC 28/51 273 1 2 3 -12 -13 1 LACH Bortles had big troubles between the 40-yard lines, going 8-of-18 for 57 yards with a sack and an interception. 24. Andy Dalton CIN 21/35 265 2 0 1 -26 -26 0 TEN On third and fourth downs, Dalton went 5-of-10 for 37 yards with a sack-fumble and only two conversions. 25. Brock Osweiler DEN 18/33 221 1 1 0 -27 -27 0 NE Coming into Week 10, the Patriots ranked 14th in coverage against tight ends, and 30th in coverage against running backs. Throwing to his backs and tight ends, Osweiler went 4-of-7 for 12 yards and an interceptions. None of those completions counted as successful plays. Four of those seven throws were failed third-down plays. 26. Tyrod Taylor BUF 9/18 56 0 1 2 -43 -55 12 NO None of Taylor's completions gained even 10 yards. Only two resulted in first downs. He only had two plays on New Orleans' side of the field: a pair of red zone incompletions. Throwing to his wide receivers, he went 1-of-6 for 9 yards. 27. Tom Savage HOU 18/36 221 1 2 3 -81 -78 -3 LARM Savage had a terrible day in the red zone, going 1-of-7 for 5 yards with no touchdowns, one sack, and two interceptions. 28. Dak Prescott DAL 20/30 176 0 0 8 -89 -109 20 ATL Eight sacks is bad. Two fumbles on eight sacks is worse. 29. Josh McCown NYJ 23/39 262 1 1 6 -101 -101 0 TB GABBERT WATCH UPDATE: Ah, this is more like it! After a terrible game in Week 1 against Buffalo, McCown had been floating around at a mediocre level of badness, and it was starting to look like there was no chance he would break Blaine Gabbert's record for worst total passing DYAR. But if there's one thing we have learned in nearly 16 years of watching Josh McCown play horrible football, it's that he's always liable to play horrible football again. McCown now has -242 passing DYAR this season and -1,573 in his career -- still a fair distance from Gabbert's mark of -1,928. However, word out of Arizona is that Drew Stanton might miss the Cardinals' Week 11 game against Houston, which means Gabbert might actually wind up playing again. And if he plays well (which has happened before -- witness this two-touchdown, no-interception game against Detroit in 2015), he might even catch McCown from underneath. Let's be honest, this race would be the most exciting thing concerning the Jets or Cardinals at this point in the year. As for his game against the Buccaneers, most of McCown's good plays came in quasi-garbage time, after the Jets fell behind by 12 points in the fourth quarter. His one touchdown came on his last pass of the game, but you can't really call it garbage time because the Jets did have a chance to recover an onside kick and try a Hail Mary at the end of the game, though that was not to be. Regardless, in the portion of this game where neither team led by more than one score, McCown went 11-of-23 for 121 yards with an interception and three sacks. The funny thing about this game is that McCown was actually effective on deep passes: 6-of-10 for 139 yards and a touchdown. Even his interception didn't kill his DYAR because it was thrown 49 yards downfield. But he was the worst passer in the league this week on short passes, with a league-high ten failed completions. Plus, you know, six sacks. That's bad too.

Five Best Running Backs by DYAR (Total) Rk Player Team Runs Rush

Yds Rush

TD Rec Rec

Yds Rec

TD Total

DYAR Rush

DYAR Rec

DYAR Opp 1. Alvin Kamara NO 12 106 1 5/5 32 0 60 53 7 BUF I have spent a lot of time poring through NFL play-by-play data the past few years. I have never seen anything like what the Saints did to Buffalo. New Orleans ran for 20 first downs in this game. The Cardinals only have 30 rushing first downs all season. The last team to rush for 20 first downs in a game: the Kansas City Chiefs in 2004. New Orleans had 12 rushing first downs against Buffalo in the third quarter alone. There have been several weeks this season in which no team accumulated a dozen first downs rushing in an entire game. Kamara himself ran for nine first downs, five of them on runs of 10 yards or more, while getting hit for no gain or a loss just once. That's the most rushing first downs any player has had in a game since Le'Veon Bell had 12 in Week 6 against Kansas City. Kamara's receiving DYAR is lower than you'd expect because two of his catches were failed third-down plays. 2. DeMarco Murray TEN 14 42 2 4/4 30 1 57 30 26 CIN A slow and steady day on the ground, with every carry gaining at least 1 yard, but none gaining more than 9. Murray did manage five first downs in there. His best catch was his 7-yard touchdown on third-and-goal. 3. Rex Burkhead NE 10 36 0 2/4 27 1 57 34 23 DEN Burkhead's day was similar to Murray's. Every run gained 1 to 8 yards, with three first downs. His best catch was a 14-yard touchdown. 4. Mark Ingram NO 21 131 3 0/0 0 0 55 55 0 BUF Hey, remember when I said Alvin Kamara was the first player with nine rushing first downs in a game since Week 6? That's not technically true, because Ingram had nine too, and his ninth came a few plays before Kamara's did. Every single one of Ingram's carries gained at least 1 yard, and good luck finding another example of that for a guy with 20-plus carries. And unlike Burkhead and Murray, he had some pop to his game too, with four 10-plus-yard runs, the longest a 25-yarder (on fourth-and-1 at that). 5. Todd Gurley LARM 11 68 0 6/7 68 0 50 20 30 HOU Gurley was hit for no gain or a loss four times, including a 7-yard loss on first down in the red zone. but he had four first downs on the ground, on gains of 11, 11, and 15 yards, plus a 34-yard gain on first-and-20. His best catch was a 43-yard gain on first-and-5.

Five Best Running Backs by DYAR (Rushing) Rk Player Team Runs Rush

Yds Rush

TD Rec Rec

Yds Rec

TD Total

DYAR Rush

DYAR Rec

DYAR Opp 1. Mark Ingram NO 21 131 3 0/0 0 0 55 55 0 BUF 2. Alvin Kamara NO 12 106 1 5/5 32 0 60 53 7 BUF 3. Dion Lewis NE 14 55 1 0/0 0 0 41 41 0 DEN A long gain of just 9, but three first downs on the ground, with only two hits for no gain or a loss. 4. Kenyan Drake MIA 7 82 1 2/2 10 0 38 37 2 CAR 5. Jonathan Stewart CAR 17 110 0 0/0 0 0 34 34 0 MIA

Worst Running Back by DYAR (Total) Rk Player Team Runs Rush

Yds Rush

TD Rec Rec

Yds Rec

TD Total

DYAR Rush

DYAR Rec

DYAR Opp 1. Melvin Gordon LACH 16 27 0 5/8 15 0 -73 -45 -29 JAC A long run of just 5 yards, only two first downs, and four hits for no gain or a loss. Only one of Gordon's catches produced a first down. He had five third-down targets and failed to pick up a first down on any of them. He also takes a big hit due to opponent adjustments for facing Jacksonville, which came into the week next to last in run defense DVOA and was 28th going into Monday Night Football. However, there is reason to think the Jaguars' run defense DVOA will continue to improve.

Um. pic.twitter.com/BTGhKPAFkN — Vincent Verhei (@FO_VVerhei) November 14, 2017

Worst Running Back by DYAR (Rushing) Rk Player Team Runs Rush

Yds Rush

TD Rec Rec

Yds Rec

TD Total

DYAR Rush

DYAR Rec

DYAR Opp 1. Melvin Gordon LACH 16 27 0 5/8 15 0 -73 -45 -29 JAC

Five Best Wide Receivers and Tight Ends by DYAR Rk Player Team Rec Att Yds Avg TD Total

DYAR Opp 1. Adam Thielen MIN 8 12 166 20.8 1 74 WAS Each of Thielen's eight receptions produced a first down, including three third-down conversions and three gains of 38 yards or more. 2. Chester Rogers IND 6 6 104 17.3 1 63 PIT Rogers' DYAR total includes 62 DYAR receiving, 1 DYAR rushing for his one carry for 3 yards. Five of his catches produced first downs, including three third-down conversions. 3. Devin Funchess CAR 5 6 92 18.4 2 56 MIA 4. Michael Thomas NO 9 10 117 13.0 0 54 BUF All nine of Thomas' receptions produced first downs, including gains of 20-plus yards and three conversions on third or fourth down. 5. JuJu Smith-Schuster PIT 5 7 97 19.4 1 52 IND All of Smith-Schuster's catches produced first downs, including a 20-yard gain on third-and-12, a 44-yard catch-and-run, and a 7-yard touchdown.