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The guy on the right was a loser until he wasn't.

The guy on the right was a loser until he wasn't.

Longtime readers of this blog know that I’m not a big fan of Matt Stafford. Last year, when most people were praising his breakout 2011 season, I questioned whether he was as good as his backers claimed. And, of course, his 2012 performance only raised more questions.

Stafford has a 17-28 career record, which in light of his recent contract extension, has caused people to criticize the Lions for giving big money to a player who is not a “winner.” There are legitimate reasons to criticize Stafford, so why would people fall back on statements like this? I’m sure Lions fans wish the team had won more games under Stafford, but that’s in the past. The real question — and the one faced by Lions management before giving him the extension — is whether his current career record has any predictive value when it comes to his future record.

Since 1960, there have been 77 quarterbacks [1]Because their first seasons as starters came after age 25, I decided to eliminate Jeff Garcia, Trent Green, Warren Moon, Kurt Warner, Ed Brown, Tony Romo, Mark Rypien, and Jim Kelly from this … Continue reading who started at least 25 games in their first four seasons and then 25 more games in years five through eight. There’s some survivor bias in the sample — if you stick around for 25+ starts in years five through eight, you’re probably a pretty good quarterback — but there’s not much we can do about that. If you run a regression using winning percentage through four years as your input and winning percentage in years five through eight as your output, you get the following best-fit equation:

0.450 + 0.20 * Old Win %

The correlation coefficient is a tiny 0.04, and the p-value on the “Old Win %” variable is 0.09. Putting aside the questions of statistical significance, there is no practical effect. Stafford has a 0.377 winning percentage, which means this formula would predict him to win 52.6% of his games from 2013 to 2016. Joe Flacco won 68.75% of his games in his first four seasons; this would say he should be expected to win 58.7% of his games in years five through eight. In other words, someone with a great winning percentage should be expected to win only one more game per season than someone with a terrible winning percentage. And that’s even assuming the results are statistically significant, which many would say they are not. [2]And, of course, it doesn’t mean that that one extra win is because of the quarterback. Presumably, like in the case of Flacco, those quarterbacks who win games early are on good teams, and … Continue reading

I know some folks tend to “skim” the math section, so let’s put the advanced tools away for a second. Here are all 77 quarterbacks, listed from biggest increase in winning percentage from years five through eight compared to years one through four. Steve Young, Dan Fouts, and Bob Griese are the three quarterbacks with the biggest jumps in winning percentages. Young, for example, won just 28% of his games in years one through four (fraud!) and then 73.3% of his games in years five through eight (Hall of Famer!).

QuarterbackYear 11-4 Win%5-8 Win%Diff
Steve Young19850.280.7330.453
Dan Fouts19730.2690.680.411
Bob Griese19670.4570.830.373
Dan Pastorini19710.2750.6150.34
Don Meredith19600.370.6440.274
Rodney Peete19890.4050.6790.273
Tom Flores19600.3930.660.267
Peyton Manning19980.50.750.25
Alex Smith20050.40.6430.243
Phil Simms19790.4120.6490.237
Troy Aikman19890.50.7290.229
Trent Dilfer19940.460.6840.224
Tony Banks19960.3770.60.223
Jay Cutler20060.4530.6750.222
Joe Montana19790.5450.7220.177
Brett Favre19920.5780.750.172
Jake Plummer19970.360.5250.165
Steve McNair19950.5260.6840.158
Chris Miller19870.2620.4120.15
Bubby Brister19860.4140.5560.142
Randall Cunningham19850.5270.6670.14
Steve DeBerg19780.1940.3240.129
Fran Tarkenton19610.3430.4720.129
Jake Delhomme19990.5450.6670.121
Norm Snead19610.2790.3980.119
Jeff George19900.2860.3920.106
Steve Bartkowski19750.4440.5450.101
Vinny Testaverde19870.3480.4440.097
Kordell Stewart19970.5630.6510.089
Brian Griese19990.50.5880.088
Mark Brunell19950.5250.610.085
Terry Bradshaw19700.6140.6980.084
Richard Todd19760.4050.4820.077
Kerry Collins19950.490.5640.074
Tom Brady20010.7390.8130.073
John Hadl19620.530.60.07
Eli Manning20040.5450.6090.064
Ken Anderson19710.5450.5960.051
Jim Plunkett19710.3750.4190.044
Donovan McNabb19990.6460.680.034
Archie Manning19710.3020.3330.031
Drew Brees20020.50.5310.031
Bert Jones19730.5610.5830.022
Brian Sipe19740.50.5160.016
Boomer Esiason19840.50.5080.008
Ben Roethlisberger20040.7090.707-0.002
Dave M. Brown19940.4520.444-0.007
Joe Namath19650.580.571-0.009
Tommy Kramer19770.4690.457-0.012
Jim McMahon19820.70.688-0.013
Bobby Hebert19850.6220.6-0.022
Drew Bledsoe19930.5420.5-0.042
Daunte Culpepper20000.4880.439-0.049
Jeff Blake19940.4390.389-0.05
Bill Kenney19800.50.441-0.059
Jim Zorn19760.4290.364-0.065
Stan Humphries19900.6670.588-0.078
Greg Landry19680.6030.519-0.085
Jack Kemp19600.7740.683-0.092
Ken O'Brien19840.5320.438-0.094
Jay Schroeder19850.6920.592-0.1
Michael Vick20010.6530.548-0.105
Jim Hart19670.5480.434-0.114
Steve Grogan19750.6270.512-0.115
Carson Palmer20040.5250.4-0.125
John Elway19830.6790.543-0.135
Eric Hipple19810.5670.423-0.144
Joe Ferguson19730.5710.419-0.152
Jon Kitna19970.5450.391-0.154
Neil Lomax19810.5670.402-0.165
Dan Marino19830.7190.55-0.169
Neil O'Donnell19910.6120.442-0.17
Philip Rivers20060.7810.594-0.188
Aaron Brooks20000.5090.297-0.212
Bernie Kosar19850.6380.394-0.244
Jim Everett19860.6040.298-0.306
Marc Bulger20020.6360.255-0.381

In Young’s case, he went from the worst team in the league to the best, which helps to explain why his winning percentage went through the roof. That’s also a good counter to the argument of using records to judge quarterbacks. In Stafford’s case, his mechanics have come under fire, and that’s probably a fair criticism. He obviously needs to improve, but it’s not like he was bad last year. He posted league-average rates in both NY/A and ANY/A in 2012, although he only ranked 22nd in my modified version of passer rating. With Stafford’s numbers, you have to remember that he’s nowhere near as good as his gross numbers make him appear, but that doesn’t make him a bad quarterback. He had Calvin Johnson but not much else last year, and I expect his rate numbers to bounce back in 2013. Without Titus Young and with Reggie Bush, there are reasons to expect a bounce-back year for Stafford. As for why he lost so many games last year? Well, I’ve already covered that.

References

References
1 Because their first seasons as starters came after age 25, I decided to eliminate Jeff Garcia, Trent Green, Warren Moon, Kurt Warner, Ed Brown, Tony Romo, Mark Rypien, and Jim Kelly from this study.
2 And, of course, it doesn’t mean that that one extra win is because of the quarterback. Presumably, like in the case of Flacco, those quarterbacks who win games early are on good teams, and those teams are more likely to stay good than the bad teams.
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