In my Schrodinger’s Bat column yesterday we updated our look at plate discipline by showing the leaders and trailers in four new metrics (Square, Fish, Bad Ball, and Eye) based on pitch location data from PITCHf/x. In addition to the leader boards we also included plots of Eye versus Fish and segemented hitters into four quadrants in order to provide a rough characterization of the continuum of approaches to plate discipline.
Not long after publication several readers noticed and gently let me know that the plots didn’t actually include all hitters due to the axes being scaled a little short thereby cutting out some of the more interesting hitters including Derek Jeter, Matt Holliday, and Vladimir Guerrero. And so in the interests of completeness here are the updated plots for all right and left-handed hitters. You’ll notice that these plots may differ slightly for some players since they are based on a few more days worth of data.
A second question raised by several readers asks how the various quadrants relate to performance. The expectation might be, as you would imagine, that players in the upper right quadrant would perform the best followed by the upper left and lower right and finally the lower left where hitters both swing at bad pitches and take good ones.
To be truthful I hadn’t taken the time to calculate this because of the relatively small sample size but spurred on by the question I did calculate EqA weighted by plate appearances for both right and left-handed hitters as shown in the following table. Here the quadrants are labeled starting with A in the upper left corner and moving clockwise.
Quadrant Count EqA
A 69 .264
B 38 .272
C 74 .269
D 25 .247
Quadrant Count EqA
A 51 .268
B 40 .282
C 43 .272
D 25 .266
And although the differences are not terribly large primarily because of the large amount of clustering towards the middle, this pretty much confirms our expectations as quadrant B (hits good pitches and avoids swinging at bad ones) does the best followed by quadrants C (takes good pitches but avoids swinging at bad ones), A (swings at bad pitches but hits good ones in the zone), and finally D (takes too many good pitches and swings at bad ones).