Running Back Rating

The true value of a good running back is that he can consistently gain yards, get first downs, and thus keep drives going. It's not as simple as looking at a back's yards per carry though. Many backs average over 4.0 ypc, yet clearly their team isn't able to just hand it off to them play after play. Granted, no team can attack a defense by constantly giving the ball to one player, yet certain backs are clearly more able to churn out the yards when it matters. So, how can this ability be measured?

To be able to consistently get first downs requires a back gain 10 yards every 3 downs (on the assumption that teams rarely go for it on 4th). Considering that the yardage gained is only really valuable if there's a first down (or touchdown) involved, it makes sense to award yards for it. To compensate, and keep the final numbers close to "real yards", we will offset the additional yards for firsts and touchdowns by removing the minimum yards needed per down (3.33) to keep gaining firsts. Furthermore, adjustments should be made for fumbles. Thus is born the Running Back Points Per Carry:

RBPPC = (Adjusted Yards - 3.33*(Attempts) + 10*(1st downs + TD)) / Attempts


Charting Percentile v RBPPC for featured backs** since 2003 shows that about one third of them combine rushing average with enough scores and fresh downs to keep their offense on the move. 3.33 is, by definition, the borderline score for a strong every-down runner.

View the complete list here.

LaDainian Tomlinson has been highly effective through 2007, but had a very low year in 2008.

Clinton Portis was stellar in Denver (5.03), but has been far less effective, despite huge yardage numbers, since moving to the Redskins (2.22, 3.20, 2.36, 3.28).

Cincinatti probably made a terrible decision to give Cedric Benson a big contract. He was borderling in 2006, but has been around 1.7 the last two years. That's just not going to cut it.

Michael Turner put the Falcons' running game on his back with a rating of 3.70 and over 23 carries a game.

The Giants didn't skip a beat transitioning from Tiki Barber to the Brandon Jacobs/Derrick Ward duo (in fact, they got even better).

Edgerrin James's decline after being a strong option in Indy (3.41, 3.36, 3.70) was so sudden (1.84, 1.99) that it pretty much confirms a weak Cardinals' offensive line. He wasn't a breakaway threat for either, and was still one of the hardest guys to bring down. Think Emmitt Smith's 1.72 in Arizona was a coincidence?

** - 150 season rush attempts