A Close Look: Penalties

Straightforward post today -- this year's Eagles committed the fewest penalties of any Reid-coached teams:

Of course, it would be pretty boring to just leave it at that, so let's put a graph together that matches up penalties committed and the average experience of the starting lineup, by season:

There's a nice little inverse relationship there at the end of the chart, but things bounced around a lot more back in the day.  Just for kicks, let's run a couple of correlations:

 

The top box is leagewide, penalties committed by and against each team (2008 season only).  I was wondering how much of an effect officiating crews might have on these stats -- as in, if the Eagles got a bunch of softy refs, maybe their stats would look artificially good.  There is a correlation there, although it's not enormous.  Feels about right, in fact.

The bottom box looks at years of experience for the starters, years as Eagles for the starters, and penaltis committed.  Not much of a result there at all.

But then I remembered something I'd written about a couple years ago.  After years of escalating numbers of penalties leaguewide, the refs suddenly started turning a blind eye to a whole bunch of infractions in 2006.  (There's another chart at the bottom here.)

So by just looking at the raw numbers, we're not getting a good sense of how the Eagles are doing on a "team-share" basis. 

Let's fix that:

 

With 32 teams in the league, each team "should" account for 3.125 percent of the penalties.  For a few years there, the Eagles were way above that level.  The last two, they've been much better.

What's really interesting, though, is running a correlation on the percentage, rather than raw, numbers:

That, folks, is starting to look a little more like a trend.