Recently, I was combing through some of my data and had a thought: why is there a metric that takes a player’s weight into account for his forty yard dash time, but not for other combine events. Next, I tried to decide what other events that weight would affect a player, and the three cone drill and 20 yard short shuttle were two of the first. So, I decided to adjust the agility score (combines a players three cone and 20 yard short shuttle times) based on their weight. The results were pretty solid, but I felt they could be better. So I decided to average this number with a prospect’s speed score, and that was when the results became clear. This data showed which running back possessed both speed and agility, which is crucial for a running back to have. If a running back is extremely fast but isn’t agile enough to maneuver through holes, he will fail. Conversely, if a running back is extremely agile but isn’t fast enough to get past defenders once he makes them miss, he will fail. All successful running backs are both fast and agile, which leads me to believe that the quickness score could be crucial for running backs.
Weight-Adjusted Agility Score
Weight adjusted agility score is exactly what it sounds like. It factors a player’s weight into his agility score. It is calculated as follows:
(weight*639)/(agility score^3)
I used 639 because the average weight of running back’s over the past ten years has been 213 pounds. I multiplied weight by three and cubed the agility score mainly to get a number that is around 100. I chose three because of the three cone drill. So it was mainly just luck, but it worked out. The five highest scores were:
- Roy Helu
- Christine Michael
- Anthony Allen
- Le’Veon Bell
- Rashard Jennings
A pretty solid list, but not great. Allen has never done anything, and Michael has let to live up to his hype (although he hasn’t gotten an opportunity yet either). Helu and Jennings have been solid, and Bell has been a star. But the metric wasn’t that telling. Of the top 75 of the last ten seasons, only 30 backs became top 36 fantasy running backs in a given season(40%). If you only include the 26 backs who were drafted in the first three rounds, the number jumps up to 62% (16) of backs becoming top 36. I felt this number was good, but could be improved. Next, I decided to average a prospect’s weight adjusted agility score (WAAS) and speed score.
Quickness Score
The quickness score attempts to measure a prospects speed and agility into one metric. It is calculated using the following:
(Speed Score + WAAS)/2
Its a pretty simple metric, but the results were slightly better than WAAS. One reason for this is that it usually places a slightly greater emphasis on the element of speed. This is because most prospects usually have a higher speed score than WAAS score. All time, 77 prospects have achieved scores of 100 or greater, which I would consider to be a good mark. Of these 77, 35 have gone on to be top 36 fantasy running backs at some point in their careers (46%). If we take out UDFA’s (only three have achieved top 36 seasons: Ryan Grant, LeGarette Blount, and C.J. Anderson) the number rises to 50%. 33 running backs drafted in the first three rounds of the draft have achieved scores 100 or higher, and 70% of them have produced top 36 seasons (23 backs). If you could hit on seven out of every ten running backs that you take in your rookie draft, your team is in awesome shape and could quite possibly be one of the best in the league at the position.Finally, backs drafted later (4-UDFA) have a pretty good success rate. Of the running backs to receive a score over 100, 44 were drafted in the fourth round or later. 12 of them went on to have top 36 seasons, or 27%. Considering that only 8% of running backs drafted in rounds 4-7 become fantasy starters in their first three seasons this number is simply excellent.
Quickness Score, WAAS Compared to Speed Score
Speed Score is a solid predictor of fantasy success. Of the top 75 running backs, 37 have had a top-36 season in their careers (49%). This number is barely better than quickness score, and is slightly better than WAAS. Of these 75 backs, 42 were drafted in the first three rounds. 31 of these backs had top-36 seasons, or 74%. Again, this number is barely better than quickness score, but is much better than WAAS. One likely reason that Speed Score is slightly ahead of Quickness Score is because every running back to enter the NFL has a Speed Score, while not everyone has a Quickness Score. This is because players almost always participate in the 40 yard dash, as it is the “flashiest” event at the combine and pro days. A much smaller percentage of players do the three cone or 20 yard short shuttle, let alone both. But, the Quickness Score was much better at finding late round prospects. Of the top 75 Speed Scores, 34 players were drafted in round 4 or later. Only 6 of them (17%) achieved top 36 seasons. So although the Quickness Score is slightly behind in other area’s, it is 37% better at finding late round producers. The slight difference in other area’s is outweighed by the greatly improved chance of finding late round gems using the Quickness Score.
