QB Defensive Support: Part 2

Last week I outlined my methodology for measuring QB defensive support, and looked at the best and worst seasons using that metric. Today’s post will explore the career numbers for the 107 quarterbacks in my study.

I originally planned to simply tally the seasonal numbers without adjustment, but that presented a problem: The top of the support leaderboard was disproportionately filled with QB’s who were exceptional at avoiding interceptions. This makes sense because throwing picks generally makes it harder to prevent the opponent from scoring, although I expected the effect to be minimal enough that it wouldn’t really make a difference. Well, it does make a difference.

To counter the interception issue, I added three point of defensive support for every marginal INT thrown in the regular season. Marginal INT’s are calculated by taking the difference between a given QB’s INT% and the league average rate1, then multiplying that difference by the number of pass attempts. I know from expected points models that the typical INT is worth roughly -3 EPA, so each marginal INT makes the defense look three points worse than it actually is. As an example, Len Dawson threw -31 marginal INT’s during his career, which “saved” 93 points for his defense. Dawson’s career support is then adjusted by -93 points.

A more rigorous study would also adjust for playoff interceptions and lost fumbles, but I don’t currently have the means for easily compiling the marginal version of those statistics. Again you’ll just have to use common sense and make mental adjustments when necessary.


By deafult, the table below is sorted by career defensive support, but you can also sort by support per game, adjusted points allowed per game, and Conventional Wisdom score. The latter is included to give perspective on how the defensive support a QB receives affects his public perception.

QuarterbackQGmAdj PA/GSupportSup/GConv
Otto Graham12015.78176.8247
Ben Roethlisberger22019.06983.2185
Tom Brady28619.86222.2384
Terry Bradshaw16016.05843.6222
Joe Flacco16719.15803.5105
Bart Starr13717.55734.2209
Russell Wilson10717.85485.1138
Trent Dilfer11616.94864.265
Len Dawson14918.44803.2185
Jim McMahon9916.34304.390
Jack Kemp11019.44193.883
Brett Favre31919.73931.2251
Joe Montana18518.83762.0292
Johnny Unitas19019.43752.0231
Troy Aikman16918.13722.2187
Phil Simms16718.33702.2116
Donovan McNabb17419.33632.1125
Craig Morton15317.53522.3105
Ron Jaworski14718.03422.387
Roger Staubach12816.73272.6205
Alex Smith15820.33061.982
Andy Dalton11220.12982.770
Ken Stabler15218.12511.7153
Drew Bledsoe19819.62441.294
Bob Griese14218.22201.5180
Brad Johnson13419.32121.699
Jim Kelly17119.11931.1170
Joe Theismann13019.31561.2130
Steve McNair15920.11450.9110
Steve Grogan13318.91421.165
Philip Rivers20021.61350.7132
Steve Young15019.41340.9217
John Elway24220.01310.5227
Bobby Layne14421.01200.8150
Kerry Collins19120.7990.569
Dave Krieg18620.1880.5100
John Hadl17120.4820.5107
Cam Newton11622.0770.785
Jeff Hostetler8719.4580.794
Doug Williams8719.8480.666
Steve Beuerlein10820.1480.474
Bobby Hebert11019.7450.466
Mark Brunell15620.7280.2101
Mark Rypien9019.5270.396
Randall Cunningham14220.4200.1100
Neil O'Donnell10920.280.181
Tony Romo13222.250.0114
Gus Frerotte10120.920.044
Nick Foles4422.9-10.070
Rich Gannon13720.6-60.0129
Babe Parilli11122.7-13-0.177
Matt Ryan16522.6-14-0.1123
Billy Kilmer11719.9-27-0.282
Vinny Testaverde21320.7-32-0.180
Jim Harbaugh14120.5-32-0.271
Peyton Manning28821.7-33-0.1307
Roman Gabriel15720.9-38-0.2110
Aaron Rodgers15722.9-65-0.4189
Matt Schaub9723.1-88-0.981
Ken Anderson16220.4-89-0.5135
Carson Palmer18222.5-92-0.594
Jake Plummer14221.6-92-0.658
Lynn Dickey11121.1-92-0.865
Tommy Kramer11121.5-94-0.869
George Blanda11923.5-96-0.8115
Eli Manning22522.5-96-0.4139
Michael Vick11622.6-100-0.969
Chris Chandler14021.3-102-0.786
Kurt Warner12722.0-108-0.8198
Jim Plunkett14320.7-110-0.8113
Bernie Kosar11521.4-122-1.181
Richard Todd10421.7-143-1.453
Jay Cutler14923.2-145-1.077
Joe Ferguson15520.9-153-1.068
Steve Bartkowski12421.6-165-1.379
Brian Sipe11021.5-171-1.687
Dan Marino25821.4-195-0.8212
Boomer Esiason17621.5-220-1.2117
Matthew Stafford12824.3-223-1.770
Warren Moon21121.6-246-1.2137
Matt Hasselbeck17222.9-250-1.593
Jeff Garcia12323.2-259-2.195
Ken O'Brien11422.7-262-2.375
Charley Johnson12023.0-267-2.274
Norm Van Brocklin11023.9-269-2.4157
John Brodie16222.7-270-1.7105
Dan Pastorini12121.6-283-2.351
Jim Everett15822.1-303-1.978
Aaron Brooks9224.3-316-3.455
Joe Namath12923.2-324-2.5132
Neil Lomax10224.3-335-3.386
Trent Green11724.1-361-3.181
Jim Hart17421.8-373-2.177
Daunte Culpepper9924.8-374-3.892
Marc Bulger9125.4-376-4.170
Y.A. Tittle17223.8-380-2.2149
Sonny Jurgensen14323.8-398-2.8155
Fran Tarkenton24621.9-407-1.7198
Steve DeBerg15922.8-409-2.665
Jon Kitna13224.2-420-3.254
Jeff Blake10225.1-437-4.361
Norm Snead16123.5-445-2.869
Jeff George12224.1-475-3.972
Jim Zorn10524.2-478-4.556
Drew Brees26023.9-496-1.9207
Archie Manning12824.1-579-4.562
Dan Fouts17323.5-582-3.4156

Much like the single season lists, the top of the career list is populated by QB’s who won a lot of rings. Otto Graham famously reached the championship game in all 10 of his professional seasons, but the accomplishment is less impressive knowing that Graham was essentially gifted a touchdown head start in every game of his career by his incredible defenses. Steeler greats Ben Roethlisberger and Terry Bradshaw owe a significant amount of their jewelry to the ferocious defenses they shared a locker room with.

Perhaps the most telling example of great defenses boosting a quarterback’s legacy is the reputation of Joe Flacco. Despite career passing statistics that fall below league average, Flacco is generally viewed as a top 50 QB of all time. While his 2012 playoff run and Super Bowl MVP are the shining beacons for his legacy, the foundation for Flacco’s reputation as a winner was built over the previous four seasons. Flacco posted a 44-20 record over his first four years and made the playoffs each season despite posting a middling ANY/A+ of 102. That’s because he was carried to wins by the dominant Baltimore defense, gifting him +422 points of support from 2008-2011. With all those victories in the bank, Flacco was dubbed a winner, a clutch QB, and better than Matt Ryan. But he wasn’t a “winner”, he just had a great defense behind him.

In order to fully grasp the relationship between defensive support and QB reputation, I think it helps to see the data presented in a visually intuitive manner. Below is a chart plotting career defensive support against Conventional Wisdom score:

The correlation between the two variables is a pretty strong .42, which indicates that a QB’s reputation is significantly affected by the strength of his defenses. The guys on the left were dealt a major disadvantage by having to overcome poor defenses, and you can see the effect by virtue of how low most of their CW scores are. A few elite QB’s made it to Canton despite bad defenses holding them back, but Fouts, Brees, Tarkenton, Jurgensen, Tittle, Namath, Moon, and Marino have only two championships on their resumes combined. Meanwhile, the likes of Graham, Brady, Bradshaw, and Starr have 21 total rings on their fingers. It’s well within reason to think that any foursome from the former group could also win 21 championships if they had the defensive support enjoyed by the latter group.

Speaking of foursomes, the same hypothesis applies to the Big 4 of the current era. Tom Brady has more rings and SB appearances than Peyton Manning, Drew Brees, and Aaron Rodgers combined. But it’s not because Brady is a better QB than the other three (he’s about even in my opinion), it’s because he’s had consistently good defenses his entire career while the others have most certainly not. In the chart you can see Brady all alone in the top right corner with +622 support, while Manning, Rodgers, and especially Brees fall on the negative side of the ledger. Imagine if Brees had an extra 1,118 points in his pocket (the difference between his support and Brady’s)…don’t you think he might have a few extra rings to show off?

  1. Technically a rolling three year average calculated by Bryan Frye