(Much) More on 1st and 10 Run-Pass Balance

In a recent article I presented evidence that offenses should generally pass more often on first down. Accounting for both the potential gains and the potential risks of each type of play, passing tends to lead to a greater net point advantage than does running. The analysis was based on a concept known as Expected Points, which measures the average point advantage an offense can expect given a down-distance-field position situation.

Expected Points incorporates all the various factors such as turnovers, yardage gains, sacks, incompletions, first down conversions, scoring, and so on. But I thought it would be helpful to dig deeper to investigate how and why passing appears more advantageous. In this article, I'll present a series of graphs comparing running and passing on first down, each one looking at a different facet of the game.

As in the original article, all data are restricted to what I call 'normal' football conditions, when time is not a factor and the score is relatively close. I looked at plays from the first and third quarters and when the score was within 10 points. This way, the effects of 'hurry-up' play and 'trash time' are excluded.

The first graph looks at series conversion rates. Generally, offenses that begin a series with a pass are more likely to convert than offenses that begin a series with a run. Note that this includes not only a conversion on the first down itself, but on subsequent plays on the series as well. Only inside the 10 yard line do runs tend to lead to conversions more often. Touchdowns are considered successful conversions. On all the graphs, be careful to note the scale on the vertical axis. Sometimes a small difference can look large, and vice-versa, due to the span of the scale.

The next graph looks at the average gain by first down play type. This includes sacks, penalties, and other losses, but is not adjusted for turnovers.

The next several graphs look at drive results by first down play types. In other words, how often does a drive end in a certain type of result based on the first down play type? Note that the graph looks at how often the drive ultimately culminates a certain way, and not how the first down play itself ends. This is an important distinction because, for example, although a pass usually increases the chance of turnover, running on first down may tend to lead to third and long situations, which usually dictate a very predictable pass. I suspect this tendency helps mitigate the increased turnover risk on the pass play itself.

The graph below looks at turnovers. Passing plays lead to a higher risk of turnover than run plays on 1st down, whether due to interception or the sack-fumble.

The next two graphs look at scoring. The first graph plots the likelihood of a successful field goal, and the second graph plots the likelihood of a touchdown. For most of the field, passing leads to a higher chance of scoring. Once inside field goal range, running will tend to yield field goals and the expense of touchdowns. But once inside the 10-yard line, running produces slightly more touchdowns.

The final graph looks at the likelihood of a drive culminating in a punt. At all field positions, running on first down is more likely to lead to a punt.

 

I think that these numbers generally support the result seen in the original article that passing is, on net, more lucrative than running on first down. Passing usually produces bigger gains, more conversions, less punts, and more touchdowns, but at a bigger risk of a turnover.

As always, the usual caveats apply.