Yesterday, I wrote how the NBA seemed to undervalue the three-point shot for many years. While the 3-point shot was consistently the better EV play, and the ratio of three-point shots to overall shots was increasing, it didn’t seem to increase quickly enough. As pointed out in the comments, one could make a pretty similar claim about pass/run ratio in the NFL.
It’s a little misleading to start things in 1970, since that’s really the beginning of the dead air era in football history. Pass efficiency was very high in the late ’40s and parts of the ’60s, so a chart beginning in 1970 would inaccurately imply a linear progression of the passing game. That said, because first down data is spotty the farther back we go, and because of the complexity involved in deciding how to treat the AFL, I’m going to limit myself today to the period from 1970 to 2016.
To measure pass efficiency, I used a familiar model: yards per pass attempt, including sacks, with a 9-yard bonus for first downs, a 20-yard bonus for passing touchdowns (excluding first downs), and a 45-yard penalty for interceptions; in other words, ANY/A with a first down bonus. For rushing, I used yards per carry, with the 9/20 yard bonuses for first downs and touchdowns. As you can see, in the early ’70s, a close to 50/50 split was pretty defensible.
It’s also remarkable how much the passing game has increased in recent times; the jump in passing game efficiency from 1978 to 2003 is roughly the same as from 2013 to 2015. Meanwhile, the graph below shows the pass ratio (i.e., sacks plus pass attempts divided by total plays) in each year since 1970:
We a similar change in pass ratio, but I don’t think any member of the football analytics community would tell you that it is commensurate with the increase in pass efficiency. There is a natural tendency for the best passing teams to pass less frequently due to the Game Script, so there is likely some sort of cap on high high the league-average — or any great passing team — will get in this regard. But 2016 saw the pass ratio jump to 59.1%, and there’s little doubt that the 60% mark will fall sometime soon, too.