Twain doesn’t actually take credit for coining the phrase, but he definitely tapped into our collective skepticism about numbers – especially somebody else’s numbers – when it comes to making an argument. Skepticism is good. It leads to more interesting, more accurate, and more predictive conclusions.
A recent Rotoworld news blurb focused on a STATS ICE claim that Eddie Lacy and Kenjon Barner led NCAA running backs in success rate last year. Success rate can be defined in various ways, but essentially the idea is to stay ‘on schedule’ in your drive. This seems to make some intuitive sense, but is it actually valuable? In order to judge the value of a stat, we need to know what the stat explains and what it predicts. If we’re going to use it to evaluate NFL prospects, what do the profiles of current players tell us about the stat?
Success Rate and the Pro Running Back
1) It’s possible team success rate has value, but the success rates of individual runners are almost entirely at the whim of scheme and usage. Last season, the Patriots’ scheme created an environment that placed three runners in the success rate top ten. Stevan Ridley was not one of them.
2) Here are the 2012 ranks of the superstars according to Advanced NFL Stats: Adrian Peterson (38), Jamaal Charles (42), Doug Martin (44), Arian Foster (53), Ray Rice (54).
3) In 1994 Barry Sanders averaged 5.7 yards per carry with a success rate of 46%. Emmitt Smith averaged 4.0 yards per carry with a success rate of 52%.
4) A prejudicial but potentially illuminating example: Let’s say Runner A gains 4 yards on first down, 4 yards on second down, and 1 yard on third down. His success rate is 67%. Runner B gains 3 yards on first down, 3 yards on second down, and runs 74 yards for a touchdown on third down. His success rate is 33%.
What does success rate tell us about Eddie Lacy and Kenjon Barner?
Almost certainly nothing. (And it may be that STATS ICE wasn’t implying that it did.)
Lacy ran behind one of the most heralded offensive lines the college game has seen. It would be a shock if anyone other than Lacy led the NCAA in success rate. I could obviously end up being wrong on the Alabama back, but there are plenty of reasons to believe Lacy is a lesser version of Mark Ingram.
Playing in one of the most explosive and efficient offenses in college football history, it would be a serious failing if Kenjon Barner hadn’t come in near the top of the list. I’ve always liked Barner. He’s a slightly lesser version of the underrated LaMichael James and should be drafted accordingly.