2011 NFL regular season wins and stat correlations

With the conference championships teed up for next weekend, here are correlations between several stats and wins during the 2011 NFL regular season. This isn't a sports blog, and I'm not making any audacious claims about being able to provide special insights. Just the raw correlations for entire teams here, next to the same for last year for comparative purposes:

Offense	2011	2010	2009
Team passer rating	.79	.68	.81
Team points scored	.77	.71	.88
Yards gained per pass play	.72	.49	.80
Total yards gained	.63	.49	.77
1st downs	.61	.51	.70
Total yards gained per play	.60	.43	.81
Pass yards gained	.59	.30*	.68
Turnover ratio	.56	.72	.69
Time of possession	.55	.61	.46
3rd down conversion %	.53	.64	.64
QB hits allowed	(.40)	(.31)*	(.53)
Sacks allowed	(.29)*	(.26)*	(.53)
4th down conversion %	.26*	(.05)*	.25*
Rush attempts	.19*	.48	.12*
Pass attempts	.17*	(.06)*	.14*
Yards gained per rush play	(.10)*	(.05)*	(.09)*
Rush yards per game	(.07)*	.35	.04*
Total team penalty yards	.04*	(.08)*	.11*
Offensive penalty yards	(.03)*	(.11)*	.04*
Pass:Run ratio	(.01)*	(.31)	.02*
Special teams
Average net punt	.38	(.08)	.27*
Average yards gained per kick return	.38	.23*	.05*
Average kickoff distance	.26*	.08*	.32
Average kickoff return yards allowed	(.11)*	(.13)*	.15*
Field goal %	.07*	.08*	.03*
Defense
Rushing yards allowed per game	(.60)	(.56)	(.58)
Points allowed per game	(.58)	(.72)	(.68)
Opponent's passer rating	(.56)	(.54)	(.47)
Yards allowed per pass play	(.35)	(.49)	(.57)
4th down conversion % given up	(.33)	.03*	(.30)
Passing yards allowed per game	.28*	(.13)*	(.24)*
3rd down conversion % given up	(.18)*	(.13)*	(.23)*
Sacks made	.15*	.30	.41
Defensive penalty yards	.13*	(.01)*	.14*
1st downs given up per game	(.10)*	(.43)	(.45)
Total yards allowed	(.09)*	(.47)	(.56)
Yards allowed per play	(.09)*	(.32)	(.54)
Yards allowed per rush	(.05)*	(.16*)	(.33)

* not statistically significant at 90% confidence

Quarterbacks are king. Teams that move the ball through the air, win. Teams that can't, don't. The difference between having a play maker with a rifle for an arm like Jay Cutler and a dud like Caleb Hanie is starting off 7-3 and finishing 1-5. Need we even mention Peyton Manning?

The 2011 season felt to this fan more like 2009, which Steve Sailer deemed the year only passing mattered, than it did 2010. Indeed, the correlation with wins and the statistics presented above between the 2011 and 2009 seasons is .84, even more rigorous than the .76 correlation between 2011 and 2010.

OneSTDV, on why the NFL is the most popular sports league in the US:

The NFL is now the ultimate sports behemoth, perhaps as a result of helmets and pads covering up black superstars and whites still dominating the marquee positions of QB and head coach.

I'm unclear as to how strong the relationship between professional sports players' demographics and the popularity among the public of the sports they play is. The NHL and MLS are both a lot whiter than the NFL while remaining far less popular than that football behemoth is. Over the last few decades, the MLB has become increasingly non-black and yet has experienced a long-term decline in popularity not just among blacks but also among whites to such an extent that football, not baseball, now clearly deserves to be referred to as America's favorite pastime. But it's hard to argue that in football's most important position, whites are in fact overrepresented relative to racial composition of the country as a whole.

While assertions that "defenses win championships" inevitably abound during postseason play, the offensive correlations are considerably and consistently stronger*. That total rushing yards allowed--not yards per attempt, but total run yards given up--correlates more strongly with wins than any other defensive stat does says a lot about offensive predominance. When defenses give up a lot of rushing yards in a game, it's often because the opposing team spent a good chunk of the second half on the ground to burn off the clock and avoid costly turnovers while protecting an early lead that the losing team's offense couldn't match.

To argue that offense matters more than defense does might seem like arguing that it only matters how hard your side pulls on the rope in tug-of-war, not how hard the other side does. Yet defenses in the NFL are mostly fungible. Tampa 2 is a bit of an exception, where the outsized importance of the middle linebacker is akin to the quarterback's, albeit to a lesser degree, but the phrase "cookie cutter" gets (over)used so often because it is accurately descriptive. If an offense can move the ball in the air against a standard NFL defense, that team is likely to be found still playing in January.

It's sometimes asserted that special teams are one-third of the game. It's not true in terms of duration and rarely feels like they are as important as downs from scrimmage. The table above confirms that feeling.

Turnovers and penalties? Turnovers, yes. Penalties, not so much. The Colts and Cowboys were the least penalized team in the league this year. The Raiders and Lions were the most penalized (even if penalties don't appear to be significant in the outcome of games, it is telling that the notoriously dirty Raiders and Detroit, which was embarrassingly chippy this season, accumulated the most fouls).

* Of course, especially stout defenses are still helpful. The Ravens and 49ers both have shots at the Super Bowl primarily because of the strength of their defenses (or, in the case of San Francisco, the astounding and league-leading +28 turnover ratio that continued in the upset against New Orleans). To oversimplify, next weekend features the Ravens and 49ers representing defensive primacy and the Giants and Patriots the power of offensive dominance. Should make for some enjoyable spectating!