Advanced stats make compelling Hall of Fame case for Jamaal Charles

Lately, former Kansas City Chiefs running back Jamaal Charles has been making a lot of Arrowheadlines — if you’ll pardon the obvious pun. And no, it isn’t because he’s said he wants to make a comeback.

It’s because:

1. Arrowhead Pride writers have often been including him in our lists of the top five Chiefs of all time. In fact, by his inclusion in these lists, he is currently ranked as the seventh best Chief of all time. This is no small thing. Of the top nine, six are enshrined in the Pro Football Hall of Fame. The other three — Charles, Derrick Johnson and Patrick Mahomes — aren’t even eligible yet.
2. He is being used in the national media as one extreme of the duality of greatness: longevity vs. peak performance. Specifically, a player like Charles is a polar opposite to a player like running back Frank Gore, whom many now claim deserves a spot in the Hall of Fame because of his long tenure as a solid running back.

While I’ve been at AP, I’ve analyzed many aspects of the performance of the Chiefs and their players. But I have yet to hone in on a player I consider to be one of the greatest running backs of all time.

So in this article, I’m going to do just that.

Disclaimer: Stats are in no way the end all be all of a player’s skill. Recently-developed advanced metrics like Expected Points Added (EPA) are certainly superior to traditional box score stats — but if you want a real look at the greatness of a player, you need to turn to the film. In the past, plenty have done that for Charles. But in this article, I’m going to stick to the numbers, doing my best to put them in the proper context.

Note: All of data for this analysis was pulled from NFL play-by-play data through the publicly available R package nflfastR, and analyzed in the Python programming language. The full code for this analysis may be found here.

Jamaal Charles — the outlier of all outliers

The dictionary definition of an outlier is a person or thing differing from all other members of a particular group or set. That certainly matches my perception of Charles’ career, but let’s see if the numbers back that up.

We’ll start with a pretty standard plot: Yards per carry (X-axis) and EPA per carry (Y-axis). This lets us see a player’s contributions on a per-play basis — using both the traditional measure of yards per carry and one that allows us to better contextualize how those yards improved the team’s chances of scoring. If you’re unfamiliar with EPA, please read here.

This graph is an absolute mess (there are 240 running backs here), but the takeaway is clear: whether you look at yards per carry or contextualize those yards by down and distance, Charles was elite during his career.

But it might be a bit unfair to compare Charles to players like Aaron Jones, or Gus Edwards, who only had a few seasons in the league; notice Charles’ much larger bubble, which corresponds to how many carries he had.

Peak performance is one thing, but how a player sustains that performance over many seasons is another. If we restrict our sample to the 72 running backs with over 1000 carries since 2000, how does he stack up?

This graph is a lot more clear.

We see that Charles is much more of an outlier when we look only at backs who have large sample sizes. Over the past 20 years, there has not been a single back who has even sniffed his huge yards per carry — and even when contextualizing those yards by down and distance (EPA) he beats all but the Chiefs own Priest Holmes. So he’s one of — if not the — most prolific rusher of the past 20 years.

But is efficiency (production per carry) all that matters for the Hall of Fame? Longevity has to play a role too, right? Otherwise, how can we say Charles is any better than a back like Alvin Kamara?

Let’s look at the total EPA Charles added to his teams throughout his career — as compared to other top backs.

Of the 72 backs with over 1000 carries since 2000, Jamaal is one of just three backs (the other being Marshall Faulk, a current Hall of Famer, and Priest Holmes) who were able to make running the ball efficient for their teams.

Many say you need longevity to make the Hall of Fame. In practice, they are likely right. Our memories are short, so we often look to record books (based on volume stats like total rushing yards instead of efficiency stats like yards per carry) to define greatness.

But is that the right way to look at it?

Take a look at Frank Gore in this graph. When we look at backs with 1,000 or more carries, he’s below average. Sure... he amassed more carries during that time frame than anyone else. But the data leads us to believe that if Gore’s teams had just decided to hand off the ball to someone else, they’d get essentially the same (or maybe better) result. But Charles looks irreplaceable. Along with a few outliers, he looks like the only back capable of making the run game look efficient.

This is certainly a crude analysis, because we’re taking a play-level stat (EPA) and assigning the play outcome all to one player (the rusher). We know this isn’t good enough to evaluate the performance of a running back, because the offensive line and passing game have a great influence on how well a running back performs. But with the exception of two years Brian Waters was on the team, Charles’ offensive lines were nothing to write home about — and the Chiefs’ passing game was often more a curse than a gift.

So while we haven’t yet figured out a way to perfectly evaluate running backs with advanced data (tracking data could go a long way here), our best guess should be that this more comprehensive evaluation would only help Charles’ case for the Hall of Fame.

To me, Charles deserves Hall of Fame recognition. Will he get it? Maybe. Maybe not. But I hope this analysis gives you comfort that if you (like me) feel he deserves it, you aren’t crazy.

Jamaal Charles mattered. This data makes it easy to argue that he’s the best running back of the last two decades — which should put him in the conversation as one of the best of all time.