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QBR and winning percentage

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By okc_dave
11 comments / new
Doug Pensinger

Bob Stoops created a minor flurry last week when he took a jab at the SEC's sudden inability to stop good QBs from putting up big numbers:

"Just a few years ago, we had all the quarterbacks," Stoops said in a small session with beat reporters, according to The Oklahoman. "And now, all of a sudden, we can play a little better defense and some other people can't play defense.

"Funny how people can't play defense when they have pro-style quarterbacks over there, which we've had. They're all playing in the NFL right now."

Stoops has a point. From 2009 to 2013, the Big 12 had the following QBs selected in the top 4 rounds of the NFL draft:

  • Josh Freeman
  • Stephen McGee
  • Sam Bradford
  • Colt McCoy
  • Blaine Gabbert
  • Robert Griffin III
  • Ryan Tannehill
  • Brandon Weeden
  • Geno Smith
  • Landry Jones
In the same time period, the SEC had the following QBs drafted in the top 4 rounds:
  • Matthew Stafford
  • Tim Tebow
  • Cam Newton
  • Ryan Mallett
  • Tyler Wilson
10 high-round NFL QBs in the Big 12 to 5 over that time period in the SEC. It's doesn't take an expert to tell you that Big 12 defenses probably had a tougher time stopping NFL talent than SEC units did.

Stoops' comments got me to thinking about the relationship between a quarterback and a team, though. I thought it would be interesting to look at a simple relationship: QB play and winning. I took each team's QBR ratings from 2009-12 and compared them to team winning percentages. The scatter plot looks like this:

Screenshot266_medium

Team QBR doesn't completely explain winning percentage, but there is clearly a relationship.

I'll do some more posts on QBR, but for now let's look at some outliers:

Best Team QBR Ratings, 2009 - current (primary QB):
1) Baylor 2013 - 97.4 (Bryce Petty)
2) Oregon 2013 - 93.5 (Marcus Mariota)
3) Stanford 2010 - 92.2 (Andrew Luck)
4) Louisville 2013 - 92.0 (Teddy Bridgewater)
5) Wisconsin 2011 - 91.6  (Russell Wilson)

Best Individual QBR Ratings, 2009 - current:

Note: all seasons are 2013 unless noted otherwise. Looks like this isn't quite apples and oranges...we'll need to look at this again at the end of the season.

1) Bryce Petty (Baylor) - 97.7
2) Marcus Mariota (Oregon) - 96.7
3) Aaron Murrary (Georgia) - 95.6
4) Russell Wilson (Wisconsin) - 94.2 - 2011
5) Terrel Hunt (Syracuse) - 93.4
6) Zach Mettenberger (LSU) - 92.3
7) Jameis Winston (FSU) - 91.6
8) Johnny Manziel (A&M) - 90.5 - 2012
9) Johnny Manziel (A&M) - 89.1
10) Teddy Bridgewater (Louisville) - 88.6

BCS Teams that overachieved their QB play, 2009 - 2012:

For these charts, I took the formula from the trendline in the chart above and applied it to each team's QBR. The formula produced a predicted winning %. I calculated the difference between the predicted winning percentage and the actual winning percentage to see which teams overachieved or underachieved based solely on their team QBR:

Team Year QBR W% Pred. W% Overachieve
Alabama 2009 57.5 100.0% 56.1% 43.9%
Iowa 2009 41.4 84.6% 40.9% 43.7%
Nebraska 2009 32.1 71.4% 32.2% 39.2%
LSU 2012 38 76.9% 37.7% 39.2%
LSU 2010 46.8 84.6% 46.0% 38.6%
Georgia Tech 2009 42 78.6% 41.5% 37.1%
Penn State 2011 33.1 69.2% 33.1% 36.1%
Florida 2012 50.8 84.6% 49.8% 34.9%
Ohio State 2012 67.3 100.0% 65.3% 34.7%
Notre Dame 2012 60.6 92.3% 59.0% 33.3%

BCS Teams that underachieved their QB play, 2009 - 2012:

Team Year QBR W% Pred W% Underachieve
Indiana 2011 43.0 8.3% 42.4% -34.1%
Minnesota 2010 59.4 25.0% 57.8% -32.8%
Washington State 2010 49.1 16.7% 48.2% -31.5%
Arizona 2011 65.8 33.3% 63.9% -30.5%
Oregon State 2011 53.8 25.0% 52.6% -27.6%
Minnesota 2011 53.3 25.0% 52.1% -27.1%
North Carolina State 2009 69.6 41.7% 67.4% -25.8%
Indiana 2012 60.2 33.3% 58.6% -25.3%
Washington State 2011 60.0 33.3% 58.4% -25.1%
Kansas 2011 42.1 16.7% 41.6% -24.9%

As I mentioned, I'll have more on QBR as the season rolls along.

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