February 20th, 2007, 02:08 PM
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#1 (permalink)
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Hall of Famer
Join Date: Nov 2006
Location: Starbucks
Posts: 8,258
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Conditional Linear Weights
DETECT-O-VISION » Preview of Conditional Linear Weights and Super DNRA
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Before we can start to understand how player statistics reflect real world value, we need to come up with a system for evaluating the events that make up a baseball game that comes as close as possible to crediting the players for the part of the event over which they have direct control. Let’s begin by discussing how best to define an event type.
When a ball is struck (by the batter), there are infinitely many possible shapes the flight path can take depending on weather conditions, the angle of impulse (the force of the bat propelling the ball), the initial contact velocity, and any spin on the ball. Statisticians have classified the trajectory types four ways. You’ve got grounders (the initial velocity of the ball is not directed upward to any degree and the ball touches the ground before leaving the infield), pop ups (the ball does not leave the sphere of influence of the infielders and spends a long time in the air), line drives (the ball does not reach very high into the air and does not touch the ground before leaving the infield) and flyballs (the ball is contacted upward and outward, leaving the infield). Two additional classes have been added to the above four by our previous database optimization, those being bunts (the batter intentionally uses his bat to deaden the ball, no swing is made) and foul flies (different from pop-ups and flyballs because they have zero chance of resulting in the batter reaching base and are not restricted to the infield or outfield).
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and
DETECT-O-VISION » Open Question: Is Team Defense Worth More?
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When BillJames created wn shares, one of the kludgy things he did to try to force the ratings to look "right" to him was to make team defense 52% of the picture and team offense 48%. Logically, it doesn't seem to fit. If you score as many as you allow, you're a .500 team, not a .490-whatever team. Offense and defense are essentially independent halves of the game, so why did James choose to make that correction?
He probably didn't know it, but he was most likely sensing two facts that can't be ignored.
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I like his ideas, what I'm wondering is are they new? Who else is working on this kind of thing?
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I'm sorry I left for a while. I needed a vaction, and then work changed substantially. I'm over 50 hour weeks, plus two hours a day of commuting time.
A few weeks ago I launched my own blog about Seattle Sounders FC and Life in Puget Sound. I won't be by these parts often as my focus has changed. Sorry about the unannounced retirement.
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