Yards per Scoring Drive Analysis

Overview

This post will look at yards gained in various drives when considering the scoring result and the number of first downs.  This post furthers the analysis from the last post (Scoring Drives – First Down Analysis).

The Data

Same drill and data set as the last post.  There are three season’s worth of data used.  This is from the 2008-2010 USC’s football team.  This comprised of 448 drives which were recorded and went into the analysis.

Again, field goals were counted any time a field goal was attempted, regardless of the attempted distance or if the field goal was made or missed.  This analysis looks at the relationship between first downs and the offense getting into scoring position, so whether or not the field goal was made is generally irrelevant.

Yards per Drive

I decided to try to take the previous analysis a little bit further and look at both the average yardage gained for each scoring first down category.  First, let us review the distribution and number of drives based on scoring.

The majority of drives fail to provide a scoring opportunity.  Now let us look at the average yards per drive.  Overall, USC averaged 35.4 yards per drive.  Now let us look at how the yardage breaks down for these drives.

This seems fairly typical and expected.  The average unsuccessful drive barely gets off the ground.  Scoring drives gain more yards since they sustain the drives and get first downs.

On average, USC gained 1.6 first downs per drive.  Now let’s break it down into the number of first downs in each drive.

As can be seen here, unsuccessful drives average only a single first down.  Field goal attempts actually average a higher number of first downs than touchdowns (2.54 first downs vs 2.38 first downs respectively).  This is surprising given the previous graph which shows that touchdown drives average a significant 13.2 yards gained more than a field goal drive.

Applying First Down Analysis

Before we apply first downs to the analysis, let us first look at a graph which was shown in the last post.  This graph shows the number of drives at each scoring result with respect to the number of first downs gained.

This graph is very important as it will keep the number of drives in each category in perspective.

Now we are ready to break the data down further and look at how many yards are gained on average based on the number of first downs converted.

This graph is actually fairly typical and predictable.  Each category typically jumped up about 10 yards for each first down gained (which should be expected logically).

However, there are a couple interesting facts that can be drawn out from this graph.  A 3 and out (no first downs) averaged only 2.7 yards gained.  Conversely, a touchdown drive with no first downs gained 40 yards on average, which implies that field position played a big role.  Scoring in such a quick manner over 40 yards could also signify the willingness of coaches to take a shot downfield after big defensive plays such as turnovers.

In addition, I found one interesting phenomenon when looking at four first downs.  Unsuccessful drives with four first downs gained more yards than field goal attempts with the same number of first downs.  My initial thought was turnovers, but turnovers should be more or less equally spread out between numbers of first downs.  Instead, this phenomenon may signify drives which ended in “four down territory.”  This is the region of the field where it is just outside of field goal range, but also too short a field to have an effective punt.  It is worth noting that it is a fairly small sample size at four first downs (three unsuccessful drives and eight field goal attempts) so this may just be a statistical blip and not an actual trend.

Conclusion

First downs play an important role in football as they keep drives alive.  Unsuccessful drives gained only 16.5 yards and a single first down on average.  Going from the 16.5 yard average of an unsuccessful drive to the 62.5 yard average of a touchdown drive is obtained by converting first downs.  Our last post showed that converting even two first downs makes it statistically more likely to score a touchdown than to end up unsuccessful.  Our next post will take a look into how many yards on a given down and distance makes a play “successful” in its ability to convert first downs.

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