Pitch Type Linear Weights by David Appelman May 20, 2009 You may have noticed a new section in the player pages called “Pitch Type Linear Weights”. First of all a huge thanks goes out to Dave Allen and his tremendous work over at baseballanalysts.com. With his help, we’ve implemented his linear weights by pitch framework using the Baseball Info Solutions pitch type data. What this section does is it uses linear weights by count and by event and breaks it down by each pitch type so you can see in runs the actual effectiveness of each pitch. There are two stats for each pitch type. The first one is preceded by a “w” and this is the cumulative runs above average for a particular pitch type. Then there are the statistics trailed by “/C” which denotes runs above average per 100 pitches of that type. This is kind of a first stab at the data and the weights we’re using are per an actual event, so singles, doubles, triples, etc… are weighted properly using data from 2005-2008. Behind the scenes we’re also calculating the data by batted ball type, so there’s always the possibility of displaying a “defense neutral” runs above average by pitch type as well. Right now we’re only showing this in the pitcher’s stats pages and for the Baseball Info Solutions data. I expect over the next month that we’ll roll this out in the PitchFx sections and the leaderboards and maybe even for Plate Discipline stats.