Penalties and the Limits of Statistical Analysis

I’m pretty sure this isn’t news to anyone, but penalties have been killing the Seahawks.  False starts, neutral zone infractions, defensive pass interference, unnecessary roughness — you name it, the Seahawks have been penalized for it.  According to Pete Carroll and others, the reason for the increase in penalties this season is the team’s youth and lack of experience.  As explanations go, this one has the benefit of sounding like a reasonable, valid answer.  It just seems logical that inexperienced players would make more mistakes, which in turn would lead to more penalties being assessed.

But do the stats bear that out?  Is there an inverse relationship between a team’s experience and the number of penalties they commit, or is there an explanation that better fits the data?  To find out, I started off by looking at stats for the last ten full NFL seasons, 2001 – 2010, although I ended up ignoring 2010 after I discovered some errors in Pro Football Reference‘s numbers for that season.  Not that it really mattered, because after a week’s worth of crunching numbers I’m left with very little of substance to show for all my work.

What I can tell you is that there does not appear to be any significant correlation between the number of penalties a team incurs and the average number of years of NFL experience for each player on the team.  The same goes for the average age of the players, who the head coach was (which is good news for Carroll), the team’s win-loss record, or the number of rookies in the starting lineup.  Looking at average years of NFL experience for just the starters on each team was slightly more promising1.  More experienced starting lineups appeared to get penalized less often than younger ones, but not consistently enough to definitely point to experience as a significant factor.  In short, I’ve got nothin’.

So as far as I can tell, it may sound reasonable to guess that there’s a connection between the experience level of a team and the number of penalties the players rack up, but the stats do not seem to back up that assumption.  It’s entirely possible that I simply didn’t examine a wide enough range of seasons for a pattern to emerge, but just examining ’01 through ’09 involved working out averages for 280+ starting lineups, and as it turns out that’s pretty much the limit of how much of this sort of thing I’m willing to do in my spare time.  If anyone else decides they want to go to the trouble of taking a more in-depth look at the data available, more power to you — I’d love to know what you discover, if anything — but I think I’ve had enough of sifting through penalty stats for awhile.

 

1 I included every player who started for at least 6 games, i.e. over 1/3 of the regular season.

Quantcast