Posted by LoboOne04 on 7/5/2018 1:07:00 PM (view original):
Do we assume that P1 is the pitch a guy throws most often? And P2 is the second-most often, and so on? I see guys who have a higher P3 than P2, or higher P4 than P1. Or high P1, P2 and P4, but a trash P3.
Plot twist- the pitchers don't actually "throw pitches" on HBD. The Sim evaluation is plate appearance by plate appearance, not pitch by pitch.
After each plate appearance the Sim does some RNG to assign a number to how many pitches took place in the at bat, but it's retroactive.
From what I observe, P1-P5 is secondary RNG (after hitter split v hitter split), expressed exclusively as average pitch as opposed to Dev chat's explanation that pitch sequence matters, which acts as the pitcher's influence on slugging percentage. In the batter-pitcher interaction, the batter is weighted about 66-33 with regards to slugging.
Also 5-pitch pitchers are scaled differently than 4, 3, and 2 pitch pitchers because the null values are not averaged in as zeroes and because the "par value" for each P is different, approximately 80-70-55-40-25 (I think it's actually closer to 82-68-54-40-24)
Because of this, pitchers with better avg pitch will keep more balls in the park and will therefore benefit from plus plays more often and have lower OAV. But there's no pitch sequence or anything like that, they're all evaluated together at the same time as an average