The NFL is becoming a passing league more and more but there is still a large contingent of coaches who believe in the value of “establishing the run.” In theory, there are a handful of benefits provided by committing to the run game: helping out the defense by controlling the ball, wearing down the opposing defense with “body blows” and, of course, setting up the play-action passing game.

That last one has been thoroughly debunked by stat nerds. There’s already plenty of evidence out there proving there’s no relationship between running success and play-action pass success, but here’s some more: Using data from the last four NFL seasons (2015-2018), I compared a team’s running performance (using Expected Points Added per rush attempt) to its play-action passing performance (using EPA per play-action dropback) and … there’s no relationship between the two.

The relationship between run percentage and play-action pass performance is a bit stronger but still insignificant…

In fact, there is stronger evidence suggesting that the reverse is true: That running more play-action passes gives the running game a slight boost. Now, the relationship between play-action percentage is still kind of weak, but it’s three times stronger than the relationship between run percentage and play-action performance…

But we have a problem of causation here: It could be that running success is leading to an increased usage of play-action because coaches would be more inclined to use play-action if they’re gashing teams on the ground — rather than the other way around. To test that theory out, I compared a team’s rushing success over the first half of a season and the difference in its play-action between the first and second halves of that same season. If rushing success does lead to more play-action passes then teams that ran the ball well early in the season would, in theory, run more play-action passes later on in the season. Well, that isn’t the case…

Not only is there no significant correlation, we actually get a negative relationship, meaning that teams that run the ball more effectively in the first half of the season actually decrease their usage of play action in the second half.

At the same time, there is a strong correlation between play-action usage during the first half of the season and the second half of the season.

That suggests that play-action usage is a philosophical thing — teams that use a lot of play-action are going to use it regardless of how well they run the ball — and not a results-based thing.

Even if running more play-action doesn’t have a direct effect on the running game, using more play-action should still lead to more situations that increase run efficiency. We know that passing on early downs is more efficient than running on those downs. And we know that play-action passes are more efficient than non-play-action passes. So using more play-action on first and second down would lead to more manageable third-down situations, when running the ball is actually more efficient than passing.

Get rid of those early-down runs and replace them with third-down runs, and running game efficiency would increase significantly.

Now, I can’t come to any firm conclusions based on any of the data I’ve presented here, but I can say this: NFL teams need to stop trying to establish the run and focus more on establishing the play-action pass.

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