Introducing: Weighted Plate Discipline Index (wPDI) for Pitchers
Today, I will attempt to develop a simple pitcher metric. My exercise will provide us with a recapitulation of the plate discipline data at our disposal, while at the same time afford us the opportunity to unearth some fascinating pitching tendencies of lesser known hurlers.
To do this, let’s start with the basic ingredients of plate discipline, from the point of view of the pitcher.
We can break down any pitch into these simple binary events:
- Was the ball thrown in the strike zone?
- Was the ball swung on?
- Did the batter make contact with the ball?