from Amazon
Friday, January 22, 2010
ICC or Intra Class Correlation
Warning! Long post!
Many of you are aware of some of the comments and assertions that Tango and I (and others) have made about regression correlations ("r") as a measure of the amount of “talent” that a particular metric reflects. For example, if you do a regression of a group of pitchers’ BABIP in one year on another year, especially if you limit your sample to pitchers who change teams from one year to the other (in order to filter out defense and park effects) you will get a very low correlation or “r”. What that means (assuming that our sample of pitchers is large enough so that we are pretty confident in the magnitude of that “r") is that there is very little “talent” associated with a pitcher’s BABIP. At least that is how we couch the “effect” in English.
What Tango and I have stated many times is that what we really mean by “very little talent” is that the spread of talent among the population that we drew our sample from (presumably in a random fashion) is small. What we mean by “small,” since words like small and large only have meaning relative to something else (a large cat may be the same size as a small dog, right?), I am not sure. Maybe it is relative to other pitching metrics - maybe it is relative to something else.
What I do know is that “there is little talent in BABIP among pitchers” is probably not the best way to couch the situation, since at some level below MLB, there could be a much larger spread of BABIP talent but that by the time MLB pitchers get to the show, they all have around the same talent, but not necessarily “no talent”, if you know what I mean. It is likely that there is a small spread of BABIP among pitchers at all levels, at least as compared to other baseball talent, for pitchers and hitters, otherwise we would probably see a larger spread at the MLB level, but that is not a given.
Recent comments
Older comments
Page 1 of 344 pages 1 2 3 > Last »Complete Archive – By Category
Complete Archive – By Date