THE BOOK--Playing The Percentages In Baseball

Tango,

I am glad that you like the work.  You are right that splitting up the data by pitch count is important.  I am going to do that in a future post.  What are the other subgroups that you include in your model?

Dave continues:
http://baseballanalysts.com/archives/2009/03/deconstructing_1.php

Fastballs and sliders show a statistically significant platoon split: there is a significantly lower run value outcome when the pitcher and batter have same handedness than when they have different. This makes sense with usage patterns for sliders, which are pitched more in at-bats when the batter and pitcher have the same handedness. You can also see here just how nasty sliders are to same handed batters, significantly lower than any other pitch.

Curveballs are interesting, there is no significant platoon split and there is a trend (although not significant) for curveballs from LHPs to have higher run value outcomes than curveballs from RHPs. This is strange as lefties throw curveballs more often than righties.

Changeups show no statistically significant platoon split. Which, again, is in line with what we expect based on their usage pattern. They are mostly thrown in opposite handed at-bats when fastballs or sliders would have a relatively higher run value.

In which publication and year (08 THT Annual?) did someone show the platoon breakdowns by pitch?  What surprised most people was the strong platoon differential for fastballs and weak one for curves.  I was not surprised by the slider as that always seems like a devastating pitch for same handed batters.  The only time that pitch is effective against opp handed batters is when it is thrown as a slurve under the hands or at the “ankles” usually by a left handed pitcher to a RHB.

That was John Walsh’s great article in the 08 Annual.

Big thumbs up.