Saturday, February 05, 2011

2010 NFL regular season wins and stat correlations

With the Superbowl a day away, here are correlations between several favorite stats and wins during the 2010 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:

Offense20102009
Turnover ratio.72.69
Points scored.71.88
Team passer rating.68.81
3rd down conversion %.64.64
Time of possession.61.46
1st downs.51.70
Total yards gained.49.77
Yards gained per pass play.49.80
Run attempts.48.12*
Total yards gained per play.43.81
Run yards gained.35.04*
Pass/run ratio(.31).02*
QB hits allowed(.31)*(.53)
Pass yards gained.30*.68
Sacks allowed(.26)*(.53)
Offensive penalty yards(.11)*.04*
Pass attempts(.06)*.14*
Yards gained per rush play.05*.09*
4th down conversion %(.05)*.25*
Defense
Points allowed(.72)(.68)
Rush yards allowed(.56)(.58)
Opponent's passer rating(.54)(.47)
Yards allowed per pass play(.49)(.57)
Total yards allowed(.47)(.56)
1st downs allowed(.43)(.45)
Total yards allowed per play(.32)(.54)
Sacks made.30.41
Run yards allowed per play(.16)*(.33)
3rd down conversion % allowed(.13)*(.23)*
Passing yards allowed(.13)*(.24)
4th down conversion % allowed.03*(.30)
Defensive penalty yards(.01)*.14*
Special Teams
Average kickoff return yards gained.23*.05*
Average kickoff return yards allowed(.13)*.15*
Average kickoff (kicking team).08*.32
Field goal % made.08*.03*
Average net punt yards (kicking team)(.08)*.27*
Total penalty yards committed(.08)*.11*

* not statistically significant at 90% confidence

When I heard a sports writer in Chicago predicting that the special teams game would be a "slaughter", as the Bears are among the best and the Packers are notoriously bad, I thought "if the post from last year has anything to say, it's that that doesn't matter."

The most notable difference from a season ago, and a possible deviation from an ongoing trend in the NFL that has seen the passing game become increasingly determinative of success and the run game meaning less and less, is that teams like the Jets, Eagles, Bucs, and Chiefs that could move the ball on the ground fared pretty well. Arguably, these are mostly mediocre teams that ended up with winning records largely due to softness of schedule. But as Steve Sailer has pointed out, 2009 was an extremely pass-friendly season even by recent standards, and 2010 was more in line with the rest of the last decade.

Penalties and turnovers, penalties and turnovers, penalties and turnovers... Or how about "turnovers and turnovers"?

Data from the last two seasons correlates at .90, essentially meaning that over 80% of a stat category and its correlation with its team's number of wins is 'explainable' by looking at what occured the year before. That is, from an obviously limited sample of only two years, the numbers put up by successful teams in '09 were largely the same types of numbers put up by successful teams this season.



5 comments:

sykes.1 said...

It has been suggested that teams that are winning switch to the running game to kill the clock. I.e., teams don't use the run early in the game to score points, they use it late in the game to preserve victory.

If true, this would affect some of your correlations, e.g., the pass/run ration (-0.31).

Audacious Epigone said...

Sykes,

Undoubtedly, both to limit turnovers and to run off the clock. It would be interesting to see what the pass:run ratio is for, say, teams with two-possession leads during the fourth quarter. It is something far less than 1, I'm sure.

That also provides some explanation as to why total rushing yards correlates modestly with wins while average yards per carry does not--teams that are winning run more (although not necessarily more effectively, since the opposing defense mostly expects them to run) and consequently rack up more yards on the ground towards the end of the game, while teams that are down air it out (and, if they are being blown out, are often given short yardage over the middle by the winning defense at the expense of extra coverage deep and near the sidelines).

Jokah Macpherson said...

Well, Green Bay certainly won the turnover battle.

Steve Sailer said...

2009 seemed like the Platonic essence of where the game has been headed while 2010 was more random.

Anonymous said...

I wonder what the turnover correlation would look like if only counting the first half of games? To reduce the effect of teams turning the ball over (interceptions) while under pressure trying to make a comeback.