News & Analysis

Quantifying a running back's blocking advantage

By Scott Barrett
Feb 26, 2018

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Sep 10, 2017; Santa Clara, CA, USA; Carolina Panthers running back Jonathan Stewart (28) celebrates with running back Christian McCaffrey (22) after a touchdown against the San Francisco 49ers during the third quarter at Levi's Stadium. Mandatory Credit: Kelley L Cox-USA TODAY Sports

The data that NFL Next Gen Stats puts out, and for free, is truly remarkable. I’m much more a fan than a critic, but at the same time, I think many of these statistics can be improved upon; currently lacking nuance or much-needed additional context. For instance, their receiver statistic “average yards of separation” is incredible in theory, but lacks greater utility without the added context of route type and whether the defense was in man or zone coverage. One additional statistic that could be improved upon is “8+D%” for running backs, which calculates how frequently a runner faced eight or more defenders in the box.

In theory, the more times a running back faced eight or more defenders in the box, the more difficult it would be for that running back to post an impressive yards-per-carry average. My issue with this specific metric is that it doesn’t incorporate how many blockers that running back had on each run. If an offense had eight blockers in the box on an obvious running situation, it makes sense that the defense would try to match that with eight defenders in the box. Intuitively, it should be easier for a runner to gain positive yardage in this situation than if a defense had eight defenders in the box to an offense’s seven blockers in the box.

So, rather than just looking only at defenders in the box, I wanted to contrast that number with the amount of blockers in the box on each running play to determine a running back’s average blocking advantage. With the help of Nathan Jahnke, I was able to calculate this. For blockers in the box, we’re excluding quarterbacks, the runner, and all players lined up like wide receivers pre-snap. For defenders in the box, we’re excluding all players lined up at cornerback and free safety pre-snap. We then contrast these two numbers to determine a players true blocking advantage on each run.

In the below chart we’re excluding all goal-line carries (carries within 10 yards of the end zone) and all short yardage situations (third or fourth down with less than four yards to go). This chart includes all running backs with at least 100 such rushing attempts, and is sorted by average blocking average.

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