Jonathan Taylor led the NFL in rushing touchdowns and rushing first downs in 2015.

It was 18 years ago that I first asked the question, why do teams run the ball? And then 11 years ago, I revisited that post. Seven years ago, I wrote Part III of this article bringing the data current through the end of the 2018 NFL season. Today, a further update.

We pondered the original question in 2008 during the nascent era of football analytics.  Back then, it was not uncommon to see people comparing yards per pass attempt to yards per rush, noticing that yards per pass attempt was much higher, and then saying it was obvious that teams run way too often (which might have still been the correct conclusion). But that missed a lot. Passing plays come with sacks and interceptions; rushing plays come with rushing touchdowns; and once you account for the full package, the gap between passing and rushing shrunk pretty dramatically.  Most interesting was the innate way the NFL evolved: despite NFL teams surely not performing the same data analysis, throughout NFL history (including the pre-merger era), there was a strong relationship between how often teams ran and how efficient running was relative to passing.

Then, in Part II, I updated the analysis with a better way of measuring both passing and rushing efficiency. In Part III, I extended that through the 2018 season. The conclusion then was pretty straightforward: passing had become more efficient than rushing, teams had responded by passing more often, and the relationship between the two was still highly correlated.  At this time, it also seemed like passing efficiency was kind of like the housing mark in the early 2000s: it only went up. [continue reading…]