THE BOOK--Playing The Percentages In Baseball

Monday, December 17, 2007

Similarity Scores for Pitch Types

What Joe does is exactly how I do my similarity scores for hitters (in my case, I use hitting components, like BB/PA, 3B/2B+3B, etc), and for fielders from the Fans’ Scouting Report (z-scores).  If you look for a fielder where you want to know where to regress him, you always regress the sample performance toward the population you draw the player from.  In my case, I know the RF population that Jose Guillen is drawn from, so, that’s where I’m regressing his UZR toward.  Same applies for pitchers.  Look for pitchers most similar in speed, movement, rotation, release (as well as repertoire), and that’s where you regress to.  For guys like Fausto Carmona and Eric Gagne, this becomes imperative to do.