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20 Jun 2016

Adjusted Interceptions 2015

by Vince Verhei

Around this time every year, we look at adjusted interception numbers from the prior season to determine which quarterbacks were actually skilled at avoiding turnovers, and which were merely the beneficiaries of good fortune (and defensive backs with bad hands). Usually we find several quarterbacks whose raw interception totals differ dramatically from their adjusted numbers, and those are the quarterbacks whose story we tell in this space. But there weren't any quarterbacks like that last year. In 2015, every quarterback threw about as many interceptions as he should have.

Before we get into the math, let's explain again how we arrive at our adjusted interception statistics:

  • We start with each player's actual interception total.
  • We then add plays where the quarterback threw a ball that could have or should have been intercepted but was not, either because the defender outright dropped the ball (which we have been tracking in game charting since 2007), or he had it knocked out of his hands by an offensive receiver (a "defensed interception," which we have been tracking since 2012). These are listed as "Drop/Def INT" in the table at the end of this page.
  • Next, we subtract plays where the interception (or a dropped interception) was tipped to the defender by a receiver who should have caught the pass. These are listed as "Tip INT" and "Tip AND Drop INT" in the table.
  • Finally, we subtract Hail Mary interceptions as well as interceptions thrown in desperation on fourth down in the final 2:00 of a game. These are listed as "HM/End Q4" in the table. In some cases we have included some other late-game fourth-down throws that fell just outside the two-minute mark, but there were none of those in 2015.

Almost all quarterbacks end up with more adjusted interceptions than actual interceptions. Only 23 of the 322 quarterback-seasons with at least 200 passes in the past nine years have had their interceptions adjusted downwards. The biggest disparity on record belongs to Jon Kitna, who threw 12 interceptions with the Cowboys in 2010, including four balls that bounced off his receivers' hands, leaving him with eight adjusted interceptions. The benchmark at the other end of the spectrum was set that same year, when Jets quarterback Mark Sanchez threw 28 interceptable passes, only to see defenders drop more (15) than they caught (13).

There's a slight flaw in that methodology, though, because we know that some interceptions will always be dropped (or broken up by a receiver). Thus, we can't look at a player's adjusted interceptions and say that is the number of picks he "should have" thrown. Instead, we need to take those adjusted interceptions and estimate how many should have been caught. Since 2007, there have been 4,306 actual interceptions in the regular season, and 5,442 adjusted interceptions. That's a ratio of about 79 percent -- in other words, a player's interception total will usually come out to about 79 percent of his adjusted interception total. We can then compare each quarterback's actual interception numbers to his expected interceptions to measure his luck (or lack thereof).

Take Jacksonville's Blake Bortles, for example. The second-year quarterback officially threw a league-high 18 interceptions last season. That includes one pass that hit a receiver first before being tipped to a defender. He threw nine other passes that were dropped by defenders. All of that gives us a total of (18 + 9 - 1) 26 adjusted interceptions, which was also the most in the league. We then take 79 percent of Bortles' adjusted interceptions and credit him with 20.5 expected interceptions. Since he actually threw 18, we can then say that he threw 2.5 fewer interceptions than he should have last year, based on average luck.

That minus-2.5 differential would make Bortles one of the luckiest quarterbacks of 2015, but not the luckiest. That honor would go to Carson Palmer, who threw only 11 interceptions despite an expected total of 14.2. Seven of his interceptable passes were dropped, and none were marked as Hail Marys or tipped passes. The unluckiest? That's a tie between Brian Hoyer and Blaine Gabbert, who each had seven actual interceptions compared to 4.7 expected. Hoyer had two interceptions on Hail Marys while Gabbert saw three passes bounce off his receivers for turnovers (nobody else had more than one). Between them, Hoyer and Gabbert threw only four dropped/defensed interceptions.

And then there's the matter of the Dallas Cowboys. The quartet of Matt Cassel, Brandon Weeden, Tony Romo, and Kellen Moore combined to throw 22 actual interceptions with only 17.4 expected. That's a collective difference of plus-4.6, far more unlucky than any individual quarterback. However, this brings us to the matter of small sample sizes. Individually, Moore threw six interceptions with only 3.2 expected, a difference of +2.8 that was higher than anyone else in the league, including Gabbert and Hoyer. Moore, though, threw only 110 passes, and falls below the 200-pass minimum we usually use for these kinds of measurements. The way this is being computed, perhaps we should use adjusted or expected interceptions as a minimum threshold, and not total passes. In that case, we would likely also eliminate both Gabbert and Hoyer from consideration. Among full-time starters, the most unlucky quarterback of 2015 was… also a tie. Eli Manning and Sam Bradford both threw 14 actual interceptions, compared to 11.9 expected interceptions. Regardless, for now, we will stick with our usual minimum of 200 passes.

Using this methodology, Sanchez's 2010 season remains the luckiest on record. For bad luck, though, Kitna's 2010 season is replaced by yet another 2010 campaign: Eli Manning threw 25 interceptions that year when he was only expected to throw 19.0. Looking at the 20 seasons since 2007 with the best and worst luck, we see that Manning is one of several quarterbacks to make both lists, including Tom Brady, Matt Ryan, Matthew Stafford, and Josh Freeman. This suggests that we really are measuring nothing but luck here, with wild swings possible from one season to the next.


Luckiest Quarterback Seasons, 2007-2015
Unluckiest Quarterback Seasons, 2007-2015
Name Year Team INT Adj INT Exp INT Diff Name Year Team INT Adj INT Exp INT Diff
M.Sanchez 2010 NYJ 13 28 22.1 -9.1 E.Manning 2010 NYG 25 24 19.0 +6.0
T.Romo 2009 DAL 9 21 16.6 -7.6 J.Kitna 2010 DAL 12 8 6.3 +5.7
D.Garrard 2009 JAC 10 21 16.6 -6.6 R.Fitzpatrick 2011 BUF 23 22 17.4 +5.6
B.Favre 2007 GB 15 27 21.3 -6.3 D.Brees 2007 NO 18 16 12.6 +5.4
A.Luck 2012 IND 18 30 23.7 -5.7 C.Henne 2010 MIA 19 18 14.2 +4.8
D.Stanton 2014 ARI 5 13 10.3 -5.3 T.Brady 2013 NE 11 8 6.3 +4.7
B.Favre 2009 MIN 7 15 11.9 -4.9 J.Freeman 2011 TB 22 22 17.4 +4.6
D.McNabb 2007 PHI 7 15 11.9 -4.9 M.Ryan 2013 ATL 17 16 12.6 +4.4
B.Weeden 2012 CLE 16 26 20.5 -4.5 E.Manning 2007 NYG 20 20 15.8 +4.2
K.Orton 2010 DAL 9 17 13.4 -4.4 M.Cassel 2012 KC 12 10 7.9 +4.1
J.Freeman 2010 TB 6 13 10.3 -4.3 G.Frerotte 2008 MIN 15 14 11.1 +3.9
E.Manning 2012 NYG 15 24 19.0 -4.0 P.Rivers 2014 SD 18 18 14.2 +3.8
T.Brady 2007 NE 8 15 11.9 -3.9 J.McCown 2014 TB 14 13 10.3 +3.7
J.Flacco 2011 BAL 12 20 15.8 -3.8 S.Bradford 2012 STL 13 12 9.5 +3.5
M.Stafford 2011 DET 16 25 19.8 -3.8 A.Dalton 2013 CIN 20 21 16.6 +3.4
M.Hasselbeck 2012 TEN 5 11 8.7 -3.7 M.Stafford 2009 DET 20 21 16.6 +3.4
N.Foles 2012 PHI 5 11 8.7 -3.7 M.Ryan 2011 ATL 12 11 8.7 +3.3
M.Ryan 2010 ATL 9 16 12.6 -3.6 T.Bridgewater 2014 MIN 12 11 8.7 +3.3
R.Tannehill 2013 MIA 17 26 20.5 -3.5 P.Rivers 2007 SD 15 15 11.9 +3.2
M.Vick 2010 PHI 6 12 9.5 -3.5 S.Hill 2014 STL 7 5 4.0 +3.1
minimum 200 passes

What you won't find in those tables are any seasons from 2015. The +2.3 differential that made Gabbert and Hoyer the league's most unlucky quarterbacks last year was the lowest league-leading mark on record. (If we did away with minimum passes, Moore's +2.8 mark would also be the lowest.) And while Palmer was the NFL's luckiest quarterback last year at -3.2, he would have finished first in that category in just one other season: 2008, when Tyler Thigpen was the luckiest quarterback at -3.0.

So here they are, the very boring numbers from 2015. Players are sorted by adjusted interceptions.

(EDITOR'S NOTE: This table was mistakenly first published with errors in the pass attempts, interception percentage, and adjusted interception percentage columns. Those errors have been fixed.)


Adjusted Interceptions, 2015
Name Team INT HM/
End Q4
Drop/
Def INT
Tip INT Tip AND
Drop INT
Adj INT Pass Att
(no DPI)
INT Rate Adj Rate Exp INT +/-
5-B.Bortles JAC 18 0 9 1 0 26 603 3.0% 4.3% 20.5 -2.5
14-R.Fitzpatrick NYJ 15 0 9 1 0 23 562 2.7% 4.1% 18.2 -3.2
3-J.Winston TB 15 0 7 0 0 22 530 2.8% 4.2% 17.4 -2.4
18-P.Manning DEN 17 0 4 0 0 21 329 5.2% 6.4% 16.6 +0.4
2-M.Ryan ATL 16 1 5 0 0 20 613 2.6% 3.3% 15.8 +0.2
7-B.Roethlisberger PIT 16 0 2 0 0 18 469 3.4% 3.8% 14.2 +1.8
3-C.Palmer ARI 11 0 7 0 0 18 530 2.1% 3.4% 14.2 -3.2
17-P.Rivers SD 13 0 4 1 0 16 660 2.0% 2.4% 12.6 +0.4
12-A.Luck IND 12 0 4 0 0 16 290 4.1% 5.5% 12.6 -0.6
10-E.Manning NYG 14 0 2 1 0 15 615 2.3% 2.4% 11.9 +2.2
7-S.Bradford PHI 14 0 1 0 0 15 530 2.6% 2.8% 11.9 +2.2
4-D.Carr OAK 13 0 3 1 0 15 571 2.3% 2.6% 11.9 +1.2
17-R.Tannehill MIA 12 1 5 1 0 15 585 2.1% 2.6% 11.9 +0.1
9-M.Stafford DET 13 0 1 0 0 14 589 2.2% 2.4% 11.1 +1.9
5-J.Flacco BAL 12 0 3 0 1 14 408 2.9% 3.4% 11.1 +0.9
6-J.Cutler CHI 11 0 3 0 0 14 482 2.3% 2.9% 11.1 -0.1
1-C.Newton CAR 10 0 5 1 0 14 493 2.0% 2.8% 11.1 -1.1
8-M.Mariota TEN 10 0 5 1 0 14 368 2.7% 3.8% 11.1 -1.1
Name Team INT HM/
End Q4
Drop/
Def INT
Tip INT Tip AND
Drop INT
Adj INT Pass Att
(no DPI)
INT Rate Adj Rate Exp INT +/-
9-D.Brees NO 11 0 3 1 0 13 625 1.8% 2.1% 10.3 +0.7
8-K.Cousins WAS 11 0 4 1 1 13 544 2.0% 2.4% 10.3 +0.7
5-N.Foles STL 10 0 2 0 0 12 334 3.0% 3.6% 9.5 +0.5
5-T.Bridgewater MIN 9 0 2 0 0 11 447 2.0% 2.5% 8.7 +0.3
12-A.Rodgers GB 8 1 4 0 0 11 570 1.4% 1.9% 8.7 -0.7
3-R.Wilson SEA 8 0 3 0 0 11 479 1.7% 2.3% 8.7 -0.7
11-A.Smith KC 7 0 4 0 0 11 470 1.5% 2.3% 8.7 -1.7
5-T.Taylor BUF 6 0 5 0 0 11 381 1.6% 2.9% 8.7 -2.7
17-B.Osweiler DEN 6 0 6 1 1 10 275 2.2% 3.6% 7.9 -1.9
7-R.Mallett BAL/HOU 6 0 5 1 0 10 240 2.5% 4.2% 7.9 -1.9
12-T.Brady NE 7 0 3 1 0 9 622 1.1% 1.4% 7.1 -0.1
14-A.Dalton CIN 7 0 3 0 1 9 387 1.8% 2.3% 7.1 -0.1
7-C.Kaepernick SF 5 0 3 0 0 8 244 2.0% 3.3% 6.3 -1.3
2-J.Manziel CLE 5 0 4 0 1 8 221 2.3% 3.6% 6.3 -1.3
16-M.Cassel DAL 7 1 2 1 0 7 202 3.5% 3.5% 5.5 +1.5
7-B.Hoyer HOU 7 2 2 1 0 6 367 1.9% 1.6% 4.7 +2.3
2-B.Gabbert SF 7 0 2 3 0 6 282 2.5% 2.1% 4.7 +2.3
8-M.Hasselbeck IND 5 0 1 0 0 6 256 2.0% 2.3% 4.7 +0.3
13-J.McCown CLE 4 0 1 0 0 5 292 1.4% 1.7% 4.0 +0.0
minimum 200 passes

With so little to say about 2015, we do have a chance to look back at some historical trends. Palmer's good fortune last season, for example, was nothing new. The veteran quarterback has finished with fewer interceptions than expected seven times in the past nine seasons now, and all told he has thrown 10.5 fewer interceptions than we would expect based on his adjusted interceptions. That makes him the luckiest quarterback since we started keeping track of these things. He's followed by Andrew Luck and David Garrard (both at -9.0, though Luck comes out as slightly luckier when we add a few decimal points), Joe Flacco (-7.8), and Kyle Orton (-6.4).

Meanwhile, no quarterback has had worse total luck than Drew Brees, whose total of 141 interceptions is 12.2 more than his expected output of 128.8. Brees is followed by Philip Rivers (+10.5), Kitna (+8.6), Eli Manning (+8.1), and Gus Frerotte (+8.0). Compare these totals to the luckiest and unluckiest single seasons we listed earlier, and you'll see there's not that much difference in the numbers between the two tables. This is another sign that we are in fact measuring random chance here, and that it's rare for a player to be especially lucky or unlucky for more than a couple of seasons.

Also, the more adjusted interceptions you throw, the more likely you are to see unusually good or bad luck. Eli Manning, Palmer, Brees, and Rivers are all in the top five in total adjusted interceptions since 2007. Jay Cutler, who is second behind Manning in that category, also shows up on expanded leaderboard in these categories.


Luckiest Quarterbacks, 2007-2015
Unluckiest Quarterbacks, 2007-2015
Name INT Adj INT Exp INT Diff Name INT Adj INT Exp INT Diff
C.Palmer 123 169 133.5 -10.5 D.Brees 141 163 128.8 +12.2
A.Luck 55 81 64.0 -9.0 P.Rivers 125 145 114.6 +10.5
D.Garrard 40 62 49.0 -9.0 J.Kitna 37 36 28.4 +8.6
J.Flacco 102 139 109.8 -7.8 E.Manning 155 186 146.9 +8.1
K.Orton 56 79 62.4 -6.4 G.Frerotte 27 24 19.0 +8.0
M.Vick 36 53 41.9 -5.9 M.Ryan 107 126 99.5 +7.5
T.Romo 104 139 109.8 -5.8 M.Schaub 84 100 79.0 +5.0
B.Favre 63 87 68.7 -5.7 J.McCown 30 32 25.3 +4.7
D.McNabb 45 64 50.6 -5.6 K.Cousins 30 32 25.3 +4.7
J.Cutler 136 179 141.4 -5.4 A.Smith 56 65 51.4 +4.7
B.Weeden 29 43 34.0 -5.0 C.Henne 63 74 58.5 +4.5
B.Roethlisberger 104 137 108.2 -4.2 A.Dalton 73 87 68.7 +4.3
R.Fitzpatrick 108 142 112.2 -4.2 B.Gabbert 31 34 26.9 +4.1
R.Mallett 8 15 11.9 -3.9 M.Cassel 76 91 71.9 +4.1
N.Foles 27 39 30.8 -3.8 S.Hill 30 33 26.1 +3.9
D.Anderson 47 64 50.6 -3.6 S.Bradford 52 61 48.2 +3.8
M.Hasselbeck 81 107 84.5 -3.5 T.Bridgewater 21 22 17.4 +3.6
C.Newton 64 85 67.2 -3.2 K.Warner 45 53 41.9 +3.1
M.Stafford 98 128 101.1 -3.1 K.Clemens 18 19 15.0 +3.0
J.Russell 23 33 26.1 -3.1 B.Quinn 17 18 14.2 +2.8
minimum 10 adjusted interceptions

Posted by: Vincent Verhei on 20 Jun 2016

7 comments, Last at 25 Sep 2017, 12:45am by GetExBoyfriendGuide1

Comments

1
by ChicagoRaider :: Tue, 06/21/2016 - 7:45am

Would the adjustments to DVOA/DYAR be significant for the +/-3 interceptions?

2
by Vincent Verhei :: Wed, 06/22/2016 - 3:08am

This is impossible to answer with any real accuracy because the circumstances for each interception are different. The costliest interception last year was worth -79 DYAR (a pick-six thrown by Matt Schaub against Miami), while Andy Dalton had an interception that was actually worth +1 DYAR after opponent adjustments (thrown on third-and-25, and 51 yards downfield so it gained Cincinnati some field postion). But the average interception last year was worth about -48 DYAR.

3
by Axe2Grind :: Wed, 06/22/2016 - 12:00pm

I would be curious to know if there is any impact from the opponents that the QBs faced. For instance if one team has particularly bad hands, are all the QBs facing them benefiting from non-interceptions. This might be especially impactful if the teams in their division are all poor defenders. For example if Buffalo, Miami and New York Jets are all bad interceptors, Brady might be the benefactor of 4 or 5 non-interceptions a year since they play 6 games each season against those teams. In the unluckiest list for the 2007-2015 I don't see QBs from some of the divisions and a few of them are from the same divisions.

IF there is some trends by division / opponents, maybe its not as random as it appears.

Jereme Brown

4
by Sixknots :: Wed, 06/22/2016 - 4:23pm

"So here they are, the very boring numbers from 2015"

Well, one number does jump out. 6.4% of Peyton Manning's passes were or should have been intercepted. All-time defense or no, how the heck do you get to the SB doing that?

5
by tuluse :: Wed, 06/22/2016 - 5:06pm

Well he only threw about half the passes for the team, and the other guy was 2.2%.

6
by Vincent Verhei :: Wed, 06/22/2016 - 7:24pm

I have said many times that the 2016 version of Peyton Manning is the worst quarterback ever to win a Super Bowl.

7
by GetExBoyfriendGuide1 :: Mon, 09/25/2017 - 12:45am

I love this adjusted adjustments as they are awesome. Read at http://getexboyfriendguide.com/