Run-Pass Imbalance by Year

I've been chronicling the imbalance in the payoffs of runs and passes on first down in several recent articles. One of the possible explanations for the imbalance is that coaches are too slow to adapt to the NFL rules that seem to become friendlier to the pass year after year. If so, maybe the adaptation to the new realities can be seen in a decrease in the payoff imbalance over recent years.

The graph below charts the difference in payoffs between passes and runs by year. As with my previous posts, data are limited to 'normal' football situations--when the score is close and when time is not yet a factor. As you can see, there may be a slight decreasing trend in the imbalance, suggesting coaches might be catching up.



There's not enough data to say for sure. Obviously, there is some random fluctuation involved from year to year. The NFL's rules keep changing, even through the current season. Plus, the Wildcat offense has created an entirely new wrinkle.

If any apparent decrease in EPA imbalance is real, I'd expect that it's probably due to an increase in the frequency of passing and an according response by defenses. But as we see below, that's not the case. Offenses are passing no more frequently now than in previous years.



An alternate explanation would be that defenses have been adapting, not offenses. Perhaps they have become keyed more towards stopping passes on first down. There's no way to know without better defensive data, so this is just thinking out loud for now.

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4 Responses to “Run-Pass Imbalance by Year”

  1. Alchemist says:

    Hey Brian, I'm sorry for being off-topic, but whatever happened to the sub-site you created where readers could contribute their own articles? I don't see it referenced anywhere on the site anymore. I'm asking because I'm launching a basketball analysis site and I thought it would be appropriate to post something about it there. I don't want to post the site here in the "regular" section of your site because that's quite spammy and not really related to your football posts.

  2. Anonymous says:

    our reference is to "offences", meaning cumulative outcome of all teams' offences, or the average. The impression I get from observing the current hegemony of teams which can (and do...or so do) pass more (notably including the most recent edition of the Vikings with the addition of a canny still-capable old quarterback), is that there is no, or at least there are very few, teams that embody this depiction -- that an inordinately large (or unbalanced, if you will) volume of the passes pile is being accumulated by the teams doing the winning -- who pass not only because their coaches are more committed to something like your broader understanding on the relative efficacies in passing and running, but also because they can. Since in this era of sideline play-calling, both sets are critical
    (mind and skill), is it possible the cumulative impression of a broad, pervasive pattern of maladaptive or retarded behavior in this respect can be generally attributed more to the latter than to the former?

  3. Anonymous says:

    i wouldnt be terribly surprised chris johnson if chris johnson was single-handedly responsible for this decline.

  4. Brian Burke says:

    Alch-It's community.advancednflstats.com. I took the link off because it's been getting more spam posts than real posts by about 1000:1. I've done a terrible job promoting it and re-formatting tables, etc. in the submissions was very time consuming--So it's unofficially dormant at the moment.

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