Is Volume or Value Better for Fantasy Football Running Backs?

Most everyone has heard the old fable of the “Tortoise and the Hare”, by Aesop, but how many times have you actually considered which side you’d be rooting for if you were there? Would you be wearing foam bunny ears and snacking on fried carrot sticks as you prepped for the hare’s elite athletic ability to dazzle you? Or would you be wearing a turtle shell over your face – Browns fans-style – and cringe as your beloved tortoise got ready to put his elite endurance to the test?

I’m Team Tortoise all the way.

This is essentially your decision on fantasy football draft day at the running back position: do you live for the thrill of electrifying agility in your players, who are racking up insane yards per attempt, or do you take the slow-and-steady plodders with lower yards per attempt, but a high number of carries?

Thus, we run out our contestants once again, centuries later: should we be aiming for upside in athleticism or upside in usage? Which of these qualities makes for a better fantasy running back?

No Napping on the Job

This is one of the biggest questions in fantasy football: how do you find a quality running back? With the emphasis going away from single-back running games, it has become more and more crucial to find value at the running back position. Many people find it necessary to grab the elite runners at the top of the draft, investing in the Marshawn Lynch and Eddie Lacy-esque players of the world. Others prefer to avoid the position until the middle rounds, banking on the theory that there is a certain level of uncertainty across the position, due to injury, workload concerns, and the shortened longevity of the position.

Our official position at numberFire is that you should try to capitalize on the most proficient running backs in the league, those elite backs, and then be wary of most of the rest. As we’ve shown, those ranked outside the preseason top-12 have a nearly identical chance of being a fantasy RB1 as they do a fantasy RB4.

Inconsistency is quite rampant in the running back position. We can never be fully sure if our investment will pay off, unless we can pick apart the nuts and bolts of why some backs score more than others. What is the secret to fantasy running back nirvana?

I Accept Your Challenge

I decided to compare running back fantasy scores from the last three seasons (2012-2014) and see what surrounding factors supported these scores: were they value-based, or volume-based? Representing volume, I’m looking at sheer touches and opportunities – rushes plus receptions, and rushes plus targets, respectively; these are our bulk categories.

In terms of value, we will use our own Net Expected Points (NEP) metric, found exclusively here at numberFire. NEP helps us take the numbers we get from the box score and assign them contextual value so they relate even closer to the game on the field. By adding down-and-distance value, we can see just how much each play and each team as a whole influence the outcome of games. For more info on NEP, check out our glossary. The categories we’ll look at for value are Total NEP – for running backs, Rushing NEP plus Reception NEP – and per-touch Total NEP.

The table below shows all of these categories and their relationships to fantasy points for running backs with 50 or more total touches any season from 2012 to 2014, using a statistical factor called R correlation. This is measured on a scale of 0.00 to 1.00 (either positive or negative). The closer the value is to 1.00, the more direct of a relationship there is; the closer it is to 0.00, the more random the association is. What kind of correlation will we find?

Incredibly, both quantity correlations fall into the “very strong relationship” category, and just Total NEP on the whole crosses the “strong” threshold. On a per-play basis, Total NEP is just a moderate relationship. This means that among running backs with 50 or more touches – a reasonable minimum of three or so per game each season – volume of touches makes all the difference. Value is important, as shown by a strong relationship to Total NEP, but it is far outstripped by the raw amount of chances a running back can get.

This is why seasons like C.J. Spiller's incredible 2012 year, where he racked up 212 fantasy points on just 250 touches, are the outlier and not the norm. It’s for this reason that fantasy owners should have soured more on the prospects for DeMarco Murray – now in a potential timeshare in Philadelphia – not to mention someone like Giovani Bernard. Unless they have an absolutely exceptional year in terms of value, they simply cannot break out of a middling role in the fantasy landscape without an increased workload. For reference, Spiller’s insane 2012 showing is one of two sub-250 touch seasons in the top-30 fantasy seasons for a runner over the past three years. The other hyper-efficient one: Jamaal Charles’ 2014.

Slow and Steady Wins the Race

What does this mean for us fantasy owners? All of the evidence we have, from probability of finishing position, to per-game consistency, to correlation of fantasy points and touches, shows that we have to preference the top-notch running backs so much more than the next few tiers of players at the position. 300-touch running backs are scarce, and last year only Murray, Lynch, Le'Veon Bell, LeSean McCoy, and Matt Forte crossed that mark. This year, I’d expect at least two of those to miss the 300-touch line.

It's interesting to note, however, that for lower fantasy point running backs, there is almost no correlation to Total NEP. Backs with fewer than 150 fantasy points in a season the last three years had just a 0.24 correlation with Total NEP, but a 0.84 and 0.85 correlation to touches and opportunities. This means that for your end-of-the-roster players, don’t worry about yards-per-carry, or any sort of value statistic: you want pure opportunity to stash. Grab only the players with the most playing time upside.

For higher-fantasy point players – those with 150 fantasy points or more – touches and opportunities still reign supreme, with 0.76 and 0.78 correlations respectively. They do, however, have a 0.66 correlation to Total NEP. This means that you should factor in value and offensive system tiebreakers when considering your frontline, top-notch running backs.

Knowledge like this could make all the difference between a fairytale ending and the thorny sting of defeat.