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Guest Post: Testing the Tape on Running Back Metrics

Brian Malone, a writer for dynastyleaguefootball.com, has put together a great guest post today. You can follow him on Twitter at @BrianMaloneFF. Thanks to Brian for today’s article!


Testing the Tape

Projecting a player’s NFL potential from his college football performance is something like predicting a player’s potential as a tennis pro from his performance in the collegiate racquetball club.  Sure, there’s correlation, but the variance in level of competition and style of play create ample noise.  No wonder folks on Twitter spend hours debating hand size: at least it’s a standardized measure, and it’s not obviously worse than things like collegiate yards per carry.

The better approach is film study.  Unfortunately, I’m not any  good at it.  Indeed, I don’t even know how to tell whether anyone else is any good at it.  But that’s a problem we can attack.  And the natural starting point is Matt Waldman’s Rookie Scouting Portfolio (RSP), which has the benefits of quantified observations, independent analysis, and a 10-year history.

The RSP includes a checklist of observed skills and abilities, including things like “Runs behind pads/Good pad level” and “Catches ball with proper hands technique.”  The RSP assigns a weight to each and combines them into what I’ll call trait scores (i.e., “Power” and “Balance”) and an overall score.

Note the three steps to this process: (1) observing the skills and abilities; (2) assessing the importance of observed skills and abilities to each trait; and (3) assessing the importance of each trait to a player’s overall ability.  The first step is off limits: we’ll take the observations as given.  But the others are fair game: we have the tools to use Waldman’s observations, plus a little math, to build a traits-based model for predicting a prospect’s success. [continue reading…]

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Guest Post: Putting Lipstick on the YPC pig

Brian Malone, a writer for dynastyleaguefootball.com, has put together a great guest post today. You can follow him on Twitter at @julesdynasty. Thanks to Brian for today’s article!


Putting lipstick on the YPC pig

We all know that that yards per carry is, as Danny Tuccitto puts it, nearly a “bunkum stat” in terms of predictive power.   Even as a descriptive tool, YPC is tolerable but unsatisfying.  Matt Forte (4.12) and Chris Johnson (4.15) had nearly identical YPC in 2015, but their paths to these numbers were notably different.  Forte rarely got stuffed behind the line of scrimmage, and he was well above average at posting four-yard gains.  Johnson, in contrast, was a home run hitter, padding his YPC with runs longer than 20 yards.

Painting a better picture

We could supplement YPC with the standard deviation of a player’s runs.  Or, as Jeff Levy suggests, we could include confidence intervals to define a player’s “true” YPC.  Both supplements add useful information, but neither smacks the reader in the face with the contrast between Forte and Johnson.  For that, we may need a visual. [continue reading…]

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