I occasionally like to look at the trend in run pass balance.
Generally the sports analytics community claims that NFL coaches are not calling the optimal play mix. Concretely, coaches don't call enough passes. Throw balance out the window.
If that hypothesis is correct, we should expect to see NFL teams exploiting this inefficiency. Since this debate has been going on for a couple of years its interesting to see what's actually happening.
Guess what? Pass attempts are up.
In 2013 NFL teams called the highest percentage of passes in league history, at 56.6%. In 2013 there were 35.4 pass attempts per game and 27.1 run attempts per game, or 1.3 pass attempts for every run attempt.
It will be interesting to see where we reach equilibrium. Will we reach a 60% / 40% mix?
Passing efficiency stays steady
In the most recent year, across the league pass NY/A was 6.2 yards while rush Y/A was 4.2 yards. A frequent response to the claim that we're seeing a sub-optimal play mix, is that teams are already at the optimal run / pass balance. Teams don't attempt more passes because additional attempts would result in smaller gains (i.e. passing efficiency would decline).
If that was true, pass efficiency should have declined over the last few years as more passes are called.
So far that hasn't happened. Passing efficiency and pass ratio have both been increasing. Teams are both calling more pass plays and getting better results from calling passes. My guess is that you can chalk that up to the rule changes.
I've include two graphs that illustrate the trend in passing efficiency.
That's the update for this year.
p.s. if you're technically inclined, below are links to the source code used to generate the charts. IMO the links are more interesting than this post.