In a league of relativity, whenever a running back rushes he either helps or hurts his team. If a running backs aggregate rushes gain more yards than what an average back might have achieved, he has helped his team; If he gains less, he ...
In a league of relativity, whenever a running back rushes he either helps or hurts his team. If a running backs aggregate rushes gain more yards than what an average back might have achieved, he has helped his team; If he gains less, he hurt it.
This would imply that Yards Per Carry is a valuable indicator of the value a player brings within his teams scheme. If a player is capable of achieving an above average YPC, it should be reasonable to assume he has pushed the overall rushing value of his team in an above average direction. The inverse should also hold true. While these assumptions are correct, YPC fails to establish the context in which the average was achieved. Marshawn Lynch and Joique Bell had essentially the same YPC however not a single person would suggest they're equivalent in value. Why? Because Lynch carried the ball ~250 more times than Bell and even though they were roughly as efficient on a per carry basis, Lynch had much more total value. In other words: Both Lynch and Bell were good, but Lynch was good more. Our dilemma however, is not comparing two like players, but rather two unlike players. To further this point, we'll need the help of our old friend Justin Forsett who In 2012 was actually significantly superior to Lynch on a per carry basis. As stated, Forsett had a much higher YPC but he achieved it over a much smaller number of carries. Additionally, both Lynch and Forsett were above average in terms of YPC, just not equally so. It is to this very situation that I have attempted to formulate a meaningful statistical comparator.
Our method of comparison will evaluate the relative value of the following 67 running backs. My cutoff was arbitrary but I feel this list hits all the staples with only a few notable omissions (Sproles).
Each player has their rushing ATT(attempts) divided by the sum of all players ATT to yield their %ATT(percentage of attempts).
Each player has their rushing YDS(yards) divided by the sum of all players rushing yards to yield their %YDS(percentage of rushes).
All runners being equal, you would expect a players %ATT to equal their %YDS. Since players are obviously not all equal, we can determine the difference between their expected contribution and their actual contribution by subtracting their %ATT from their %YDS. %YDS-%ATT can be interpreted as total value above average.
We can then convert a players %YDS-%ATT into YAA(yards above average) by multiplying the percentage against the total number of yards. This is merely the same number presented in a recognizable fashion; it can also be interpreted as total value above average.
Dividing YAA by a players ATT gives us their YPCAA (yards per carry above average)
Peterson brought ~1.41% surplus value or in other words ~614 surplus yards on his 348 carries for a per carry average of 1.76 above your normal player.
Adrian Peterson, RB
C.J. Spiller, RB
Jamaal Charles, RB
Marshawn Lynch, RB
Alfred Morris, RB
Frank Gore, RB
Justin Forsett, RB
Doug Martin, RB
Andre Brown, RB
Bryce Brown, RB
Ahmad Bradshaw, RB
Chris Johnson, RB
Joique Bell, RB
Kendall Hunter, RB