from Amazon
Friday, September 09, 2011
Spread in talent
The primary reason something stabilizes is based on the spread of true rate of whatever entities are involved.
As an example, hitter K/PA stabilizes very fast because there is a wide range in talent in terms of striking out.
The reason you find the wide range in talent is if a player is selected based on that component.
For a nonpitcher, having a high or low K/PA is not that important, because there’s tons other things a nonpitcher brings to the table to counteract the negative effects of a high K/PA. So, by not selecting specifically on that, we see a wide range in talent.
For a pitcher, having a high or low K/PA is important, because there’s comparatively little else he can do. And that’s because most pitcher’s have a small spread in talent on balls in play: they’ve been selected to make sure that the 75% of the time that they pitch to contact, that they don’t get blown away. So, they’ve already been selected based on BABIP, so they don’t necessarily selected based on K/PA.
This is why GB rates for pitchers stabilize very fast: pitchers are not selected based on being GB or FB pitchers.
(Of course, there are other things that you aren’t selected for, that doesn’t stabilize: that’s because it has very little value.)
Goalies in hockey are very tight in their save percentages because that’s the ONLY thing they can do. So, you have no choice but to see a tight range (on a per shot basis). However, since they face some 1500 shots per season, what is hidden on a rate basis is more visible on a volume basis.
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Inspired by this article.