Run Area Effects on Rushing Efficiency

Updated: June 13th 2018

One topic rarely covered by fantasy writers is the run area scheme of NFL offenses and its effects on rushing efficiency.  By run area, I simply mean where teams tend to run the ball along the offensive formation.  Do teams utilize outside runs heavily or rely on a more “between the tackles” philosophy and does the scheme affect expected rushing efficiency?  I examine NFL play-by-play data from 2014 to 2017 compiled at NFL savant to help answer the question.

Run Area Scheme

NFL teams, on average, maintain a fairly uniform run distribution across the formation as can be seen from Figure 1 below with a slight tilt toward plays in the middle of the offensive line.  Runs around the end make up a little over 23 percent of all rushes where center gap runs account for just under 27 percent.  While rushing distribution is somewhat uniform across the NFL, Table 1 details plenty of variation between NFL teams.  For example, the average run rate at the guard gap is around 25 percent in the NFL but some teams ran almost 50 percent of their plays toward the guard gap and others as little as 9 percent last season.

 

Figure 1.  NFL Rushing Distribution

Table 1.  Maximum and Minimum NFL Team Run Area Rates, 2017

The distribution of NFL runs may be tilted toward the interior of offensive lines but rushing efficiency clearly gains more toward the exterior.  Figure 2 displays a clear increase in yards per carry as rushes move from the center to the end.  This trend holds steady each year of the data set producing a reliable relationship.  NFL teams gain almost a full yard per carry more on end runs when compared to rushing at the center gap.  A couple of possible explanations quickly come to mind when looking at the rushing efficiency leaps as we move farther from the middle of formations.  First, the defender density (number of defenders per yard of field width) typically decreases as we move farther from the center.  This produces larger rushing lanes and correspondingly more opportunities for big plays as we move away from the middle of the formation.  Second, typically less stout run defenders occupy more of the area as we move to the outside of the formation.  Pulling offensive lineman are able to match up against outside linebackers and defensive backs instead of the hulking defensive tackles on the interior.

Figure 2. NFL Rushing Efficiency

Why then do teams not use exterior run schemes more often given the big efficiency differences?  Figure 3 helps provide an answer.  The expected increased yardage of outside rushing comes at a cost.  End runs result in almost double the rate of negative runs when compared to runs up the middle.  The benefits of those wider rush lanes can work in the opposite direction.  Defenders on the exterior deal with less linemen and have increased open areas to defeat blockers allowing more plays in the backfield.  Some coaching staffs display risk averse tendencies (possibly too much) not wanting to put their offenses in increased poor situations which result from using more end runs.  There are also other situational factors that dictate the use of more center runs.  Center runs have better odds of gaining short positive yardage which make them better bets for short yardage plays (think 3rd down and a yard to go) to extend drives.

Figure 3.  NFL Rushing Distribution, End vs. Center Runs

Best and Worst Team Situations for Rushing Efficiency

Taking into account the above data we can get a real feel for why some teams struggle with efficiently running the football.  I used each team’s directional running distribution and offensive line run blocking rankings (utilizing a composite of PFF offensive lineman run blocking grades) to model the expected yards per carry and compared that to actual rushing efficiency.   The benefit of this simple model is that it gives us a measure of team expected rushing efficiency independent of the running back play.  Table 2 gives us a look at some of the best and worst team situations in the NFL from 2017 for running back efficiency.

 

Table 2.  2017’s Best and Worst Situations for Rushing Efficiency

None of the top or bottom rushing situations should really shock anyone.   The top-5 situations all possessed top-6 offensive lines and all but Dallas ran heavy edge schemes.   Chicago might surprise some near the top.  It should not.  The Bears have one of the most underrated run-blocking units in the league and, despite running back Jordan Howard’s reputation as a between the tackles grinder, actually utilize one of the most running back-friendly schemes with the lowest rate of center runs and the second highest percentage of end runs.  The bottom-5, conversely, are generally characterized by bad run blocking units with running schemes emphasizing up-the-middle concepts and/or lack of perimeter runs.  Houston should surprise no one at the bottom of this list.  The offensive line does not contain a single player one would consider starting-NFL caliber and the Texans ran the lowest rate of those high-leverage end runs in the league.

Effects on Yards Before Contact

You may have read one of the many fantasy articles out there which try to employ yards before contact (YBC) as a measure of an offensive line’s effectiveness.  Be very careful with this interpretation.  While an offensive line certainly affects YBC, the data indicates run area scheme also has a substantial impact.  As we examined before, end runs result in a far higher rate of negative runs and correspondingly more hits in the backfield.  This means YBC numbers can diminish for teams with heavy end run schemes, even those with very good offensive lines.  Contrarily, teams which use a heavy interior run scheme may see YBC boosted beyond what the offensive line skill may dictate.

Keep Rushing Efficiency in Proper Context for RSO Leagues

Consider a running back receiving 250 carries (that would have been the 9th most from 2017) who gains an extra 0.5 yards per carry.  That translates to an extra 125 yards and 12.5 fantasy points in most leagues or less than a single fantasy point per game.  This translates to only a couple of extra touchdowns in a season.  Remember that variations in rushing efficiency plays a relatively minor role in running back scoring when compared to the impact volume and touchdown volatility have.


Bio:  Bernard Faller has degrees in engineering and economics.  He currently lives in Las Vegas and enjoys athletics, poker, and fantasy football in his free time.  Send your questions and comments (both good and bad) on Twitter @BernardFaller1.

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