The guys over at Football Outsiders have a stat called the Speed Score, which they use for identifying running backs, based on the relationship between the 40 time and the player's weight. The formula is (Weight * 200)/(40 time^4). Players with scores over 110 tend to be good. Scores of 100 tend to be average. Players with scores in the 90s or lower tend to disappoint. Overall, it is an adequate metric for judging running backs, but it doesn't answer all of my questions. Speed Score, in essence, is a measure of the power or momentum a player is generating when they are near their top speed, but basing this off of the 40 time presents some issues. A player's long speed isn't going to be displayed nearly as often as their short area explosiveness. Speed Score is more about a player's ability to have a long breakaway run, and less about pounding the ball between the tackles. Speed Score, to me, is not a bad measurement, but is probably somewhat more suited to the fantasy football crowd.
I'm going to throw out a couple of ideas here (some are fairly obvious, and some are possibly stupid), and we'll see how things work out. I'm going to show a bunch of different scores for different running backs, but not show who these running backs are. We're looking to see how well the numbers can describe the way a player will end up playing the position. I'll list the player's 40 time, and Speed Score, which will be our measure to suggest the ability to break long runs. The player's time at the 10yard split, and their 2nd Gear Score, will also be tossed in there, in an attempt to better describe how a player builds their speed. I'll list the player's Kangaroo Score, to show short area explosiveness and power, which should relate to pounding the ball between the tackles. Sometimes a player's ability to break the long run is less useful than their ability to grind it out for 2-3 yards. I'll also list how the player scored on the agility drills, which should relate to their elusiveness, and some have also theorized, to their ability to be used as a receiver (this correlation is a bit more suspect, but interesting to consider). Kangaroo Scores and Agility Scores will be given, as always, in terms of how many standard deviations the player was from the average result for their peer group, either in a positive or negative direction.
So, based on the scores, try to imagine what sort of running back the player is. Is he a player that tends to run outside the tackles, or can he pound it inside? Is he likely to be eluding people, or running them over? Or, does he have the ability to succeed in multiple ways? Later in this post, I'll list who the players are, and you can judge how well your guesses turned out.
Player 40 Time 10 yard 2nd Gear Spd. Scr. Kangaroo Agility
What do you make of the players in the N, O, P, Q cluster? They all seem to have average to poor Kangaroo Scores, suggesting that they wouldn't excel as power running backs. They also all show good speed and agility, so they will probably be better suited to running outside the tackles and trying to evade people. Perhaps, if there really is a correlation between agility scores and being a receiving running back (somewhat debatable) they might do well here also.
Players A, B, F, H, L, S, V, and X, show much better Kangaroo Scores, which might suggest that they would be above average at running between the tackles. Still, many in this group are also showing the speed and agility to run outside also. A, B, H, V, and X also show good agility, so you might expect them to be better receivers and show some elusiveness.
Do players B, D, F, G, H, J, K, N, S, and W, appear to have a rather good second gear? Perhaps, beyond whatever quickness they possess, they might have even more deep speed than their 40 times might indicate.
Does player M appear to be a bozo who excels at nothing? Actually he appears to be bad at everything.
So, who are these guys?
I wouldn't say that the results from this are perfect, but I think they are fun to consider. There are two players in particular where I'm not sure if the numbers accurately capture the player's skills. LeSean McCoy (player I.) appears slower and less powerful on paper, than I feel he is in real life. It does credit him with being very agile though, which I think is true. The same could be said for Alfred Morris (player C.). On paper, he seems to be a moderately elusive, slightly more powerful than average, type of guy, with very poor speed. Still, I don't expect the numbers to tell the whole story every time. There will always be people who exceed your expectations, as well as people who fail to live up to their ability. Still, I have to admit, that I tend to be very wary of betting against the numbers.
As for Mark Ingram (player M.), yes, I think the computer would be correct to come to the conclusion that he is probably a bozo, who shouldn't have been taken in the first round. If fat, drunk and stupid is no way to go through life, then plodding, weak, and lacking agility is similarly not a likely path to success for a running back.
As always, this doesn't eliminate the value of actually watching them play. This is just something to consider along with all of the other facts that are out there. I think there are still very good reasons to watch a player's game tape, as some players are clearly more creative with how they go about using their physical gifts. This also doesn't even begin to delve into their college stats, though I may get into that subject at a later time.