SABR: Challenging Assumptions

Members of SABR–and if you’re not one, you should be–returned from work to find a treat in their mailboxes yesterday: the latest issue of the Baseball Research Journal, the fine publication issued by the organization that has done so much to change the way we think about, and even play, the game.

Some of the intriguing information in this issue:

-Robert Adair, Sterling Professor of Physics at Yale University and former National League “official” physicist (during the Bart Giamatti reign), reveals that the Questec system’s high error rate makes it a statistically useless tool for judging individual performance of umpires.

-Former MLB pitcher Dave Baldwin (a PhD and a specialist in systems engineering) and Terry Bahill explain the physical and physiological reasons why some fastballs appear to “rise” or jump when they reach the strike zone (they don’t; it’s an optical illusion).

-Frederic Reamer, yet another PhD, uses the statistical formula known as Spearman’s Rho to gauge the accuracy of the 2003 preseason forecasts by the experts at ESPN.com. The results: they did a pretty good job, but if you just picked the same order that the teams had finished in 2002 (basically, a default prediction), you would actually have done even better.

And there’s plenty more.

4 comments… add one
  • Being so Sabermetrically inclined must be a real blast as a Yanks fan, huh. Really outsmarting the game with those limited resources.
    Get a real team.

    Eliot February 18, 2004, 3:22 pm
  • Eliot – thanks for commenting, but I don’t see what YF’s post had to do with the Yankees or his allegiance to them. We appreciate the visit, in any case.

    SF February 18, 2004, 4:47 pm
  • Not to put too fine a point on it, but re: item 2 – no sh*t! Rising fastballs are, unless thrown by a pitcher upwards, a physical impossibility. They would, by their nature, if thrown conventionally and down the mound, otherwise defy gravity. Still, being a visual person and all, I am interested in the illusory aspects of them and the attendant explanation. I will purchase my subsciption presently…

    SF February 18, 2004, 4:54 pm
  • A note in my own defense, and an explanation
    First, in response to the comment by Eliot, would he suggest that all Yankee fans up and resign from SABR? I’m not sure the organization would find that prospect appealing.
    As for SF’s legitimate question question regarding the illusion of the jumping fastball, here’s the capsule explanation:
    The eye is, physiologically, not fast enough to continuously track the ball from the pitcher’s hand to the point of contact. At some point when the ball is on the way to the plate, the eye will jump to the position where, based on reflexive memory of other pitches thrown at the same velocity, it expects the ball to be. However, if the speed of the ball is underestimated–ie, if the ball is moving faster than the batter predicts–his eye (and swing) will go to a point slightly below the actual position of the ball, because he will think that ball will have been airborne for slightly longer than it actually has been, and therefore will have dropped a few crucial inches from its actual position (because all balls drop at the same rate). So when the eye jumps to the new position it will find the ball at a point higher than anticipated. Hence the apparent jump. (The authors do a dramatically better job of explaining this effect.)
    What is most useful about this analysis is that it shows just how crucial changing speeds is. Just ask Jaime Moyer.

    YF February 19, 2004, 4:34 pm

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Next post:

Previous post: