Run Value by Pitch Type and Location
In my first post, I noted Tango and Lichtman's comment that run value by pitch location analysis was limited when averaged across pitch types and pitch counts. In this post, I will address the first concern by looking at the run value by pitch location of the different pitch types separately (but again averaging across count).
I split the data by handedness of the batter and the pitcher and then split this information into four different pitch types (based on the pitch fx classification). As in the first post, all images are from the catcher's perspective so that a right-handed batter stands to the left of the strike zone and a left-handed batter stands to the right of the strike zone. At the top of each image is the proportion of pitches between the given handedness combination made up of the given pitch type (out of the four pitch types considered). Counting just these four pitch types, 60.9% of pitches from a right-handed pitcher to a right-handed batter are fast balls.
Of the pitches considered, fast balls made up over 60% of pitches in each handedness combination. Thus, the overall run value maps in the first post are largely reflecting the run values for fast balls. But there are some small differences:
Changeups are overwhelmingly thrown when the pitcher is of the opposite handedness of the batter. Additionally, the few times when changeups are thrown when the pitcher and batter have the same handedness may be a highly non-random sample: pitchers with outstanding changeups and good pitcher's counts (this is just speculation). Because of this and the small data size we should not read too much into the same-handedness changeup maps.
Curves are thrown in relatively constant proportion in all handedness combinations, expect for leftie/leftie where they are thrown a little bit more.
Sliders are thrown more when the batter and pitcher have the same handedness (the opposite of changeups), thus the same caveats apply to reading too much into the opposite-handedness maps.
These separated by pitch type maps allow us to make some additional insights into the overall maps in the first post. The negative to neutral region above the strike zone is mostly the result of fastballs, while the negative to neutral region below the strike zone is mostly the result of non-fastball pitches. Within the strike zone, most pitches have the same overall structure with the center of the zone and down and in having the highest run value, although the pattern is not quite as apparent with curveballs.