In which BP debuts a new column, called Lies, Damned Lies.
Strikeout Rate, Redefined
April 16, 2003
Abstract: Nate explains why measuring pitchers’ strikeout and walk rates using outs as a denominator–i.e., rates per nine innings–is less useful than measuring rates per batter faced. This is fairly common practice now, but a) not the most common practice, and b) he takes it a step further to show how K/9 creates a notion of linearity that is actually not consistent with real life.
Key Quote: “Implicit in all of this is that ERA doesn't display a particularly linear response to batting events. When evaluating offensive performance, it's safe to ignore the non-linear nature of run production except in the extreme cases–like, say, Barry Bonds and a random group of eight mortals. The same can't be said for pitchers because they, by the very nature of their job description, face a series of opposing batters in sequence. Little differences go a long way. The problem is, this fact is obscured when the inputs are denominated in the same units as the outputs.”
Super Duper Duper Key Quote: The front half of this piece is actually where Silver lays out a decent portion of his worldview, and in very simple terms his approach to using data. Not just metaphorically; he literally foreshadows the jump into superstardom that he would make a half-decade later:
We know better, of course, just like we know not to trust any financial disclosures coming from Herr Selig, or directions coming from a cabbie at the train station, or poll numbers coming from just about anybody. In a number of surveys, most Americans didn't support unilateral military action in Iraq when multilateral action was first presented to them as an alternative–yet when that option was withdrawn from them, both literally and figuratively, a solid majority came out in favor of going in alone. Now, Patriotism has a lot to do with that, and well it should, but so too does question order and non-neutral wording. We know all of this, of course, because we're smart.
Hey, I think I'm pretty smart, too, and I have an annoying little hobby of trying to deconstruct print and television advertisements on the spot. It's not out of any postmodern malaise so much as the naive hope that by decomposing something, I'll somehow be able to avoid succumbing to it. But open up my wallet, and you'll find a Starbucks Card, a Banana Republic Card, and two out of the three pieces from the yellow group in the McDonald's Monopoly game from a few summers ago (damned Marvin Gardens).
All of this is a roundabout way to say that, while we can strive to be as critical as we want to be, the problem with taking something for granted is that we never realize that we're doing it until it's too late. One of those things–ranking somewhere in importance between wrinkle-free chinos and the siege of Basra–is the use of pitching statistics that are denominated in innings pitched.
There’s so much there. He’s told us that he is suspicious of all data, despite himself being a champion of data; that he is particularly suspicious of the provider side of data; that he, too, is a provider of data and should be treated as fallible; that he himself is aware of his own fallibility; that baseball is one of just many fields in which he sees opportunity to explore the nature of truth; but that he doesn’t simply view these questions as academic, or amusements, or puzzles, but as real-world matters with real-world consequences. In these three paragraphs, you could say he foreshadows his career turns, but more than that you could say he lays out all the reasons we never lost interest in him.
On the Nate Silver Must-Read Scale: For the topic, 1, but for the writing 3.