Think of a simple task that you do hundreds or thousands of times each year. Maybe it’s taking your phone out of your pocket. Maybe it’s grabbing a coffee mug off the shelf. Something simple, that you almost never screw up. Almost. One time out of 200 you might drop the phone. One time out of 500 the coffee mug slips and shatters. These are common man’s equivalent of fumbles. Fumbles for any NFL running back are rare, but a few high profile cases can get a back the “bad hands” label, implying that they are more prone to fumbling than their peers.
But are running backs with bad hands really a thing? Or are fumbles just random unavoidable occurrences? To answer these questions. we grabbed running back data from the last four NFL seasons (2012-2015), specifically the rushing attempts and fumbles. We only included backs with at least 200 rush attempts across the four seasons we examined. Figuring out which backs are more or less prone to fumbling could give you an edge in the fantasy football game, particularly if your league carries heavy penalties for fumbles.
The first thing we did was plot out the number of rushing attempts for each running back compared to their total fumbles (each player is one dot in the figure below):
We see a pattern that we would expect, more rushes leads to more fumbles. But if workload alone was the reason fumbles happened, all the dots would fall pretty neatly around the dashed trend line. But that is not the case. There is a lot of scatter (noise) associated with the dots, which tells us that total rushing attempts is an important factor, but it’s not the sole predictor of how many times a player fumbles. Put into other words, if a running back rushes 400 times, we would predict them to fumble about 4 times (conveniently, the average number of rush attempts per fumble is about 100). In real life, whether that running back fumbles more or less than 4 times over 400 rushing attempts would be the result of “bad hands” or “safe hands”. Running backs above the line in the previous figure fumble more often than predicted, those below the line fumble less often than predicted. Now we’ll break that down who those players are.
Which running backs have bad hands?
There are some running backs that fumble far more often than we would predict they should based solely on their workload. These are the running backs, that through past performance, have earned the bad hands label. In this table we show predicted fumbles for each player (based on the number of carries), how many times they have actually fumbled, and the difference (negative numbers mean more fumbles than predicted). Jamaal Charles, and his +6 difference, has fumbled 6 more times than we would have predicted based on workload along. That’s not great.
Which running backs have safe hands?
Some running backs fumble far less often than we would predict based on their workload. These are the safe hands crew, starting with the safest (least fumbles compared to predicted) at the top of the list and the next safest following:
Running backs not appearing on either list can be considered relatively average in terms of how often they fumble.