Created by Bill Barnwell and introduced in
Pro Football Prospectus and
ESPN Insider back in 2008, Speed Score is one of Football Outsiders' metrics for evaluating running back prospects. It's built on the simple idea that smaller backs tend to run faster than larger backs, so we should be more impressed by a 4.5-second 40-yard dash from a 220-pound back than the same clock reading from a 170-pound back. As such, Speed Score incorporates a back's official time in the 40-yard dash with his weight to produce a measure of his speed given his size using this formula:
(Weight * 200)/(40 time^4).
The average running back who makes it to the NFL will have a Speed Score around 100, with most running back prospects falling between 85 and 110.
There's no such thing as a can't-miss prospect, but players who breach that 110 score threshold have phenomenal track records. We went back and looked at every running back prospect who ran at the combine between 1999 and 2013 and checked their average yards per season over the first five years of their career. The 110+ club was between 2.5 and 4 times more likely to hit each and every benchmark then the average running back.
Speed Score 2018 | Football Outsiders