Balls in play, by count
I'm sure I'm not the first to look at this but I had to see it for myself. I'm looking at the results on balls in play by different counts. Is a hit ball more likely to be a hit when the count is 3-1 as opposed to 1-2? The answer seems obvious, and it is in fact true, but I still needed to quantify it. The numbers presented here are "safe percentage", which is hits (excluding homers) plus reach on error divided by balls in play.
I divided the numerous possible counts as hitters, pitcher, and neutral:
Hitter's counts: 3-1, 3-0, 2-0
Pitcher's counts: 0-1, 1-2, 0-2
All others are neutral.
The results, first for ground balls:
For fly balls you actually see a better safe% in pitcher's counts, but that is an illusion, since by looking at balls in play I'm removing homeruns. And the hardest hit flyballs in hitters counts turn into homeruns. Adding back the homers I get:
So a pitcher who maximizes pitching ahead in the count (think Greg Maddux in his prime) can have a 20-40 point advantage on balls in play over a guy pitching behind (Brian Fuentes recently). This is a potential enhancement for TotalZone, but in practice it barely makes a difference. It is not a difficult thing to add into TotalZone, and I will use the ball/strike count as a parameter in the future, it makes very little difference. Most player-seasons are unchanged, at least once the results are rounded to the nearest run, and didn't find any player season where the result changed by more than one run. Probably
The change is not worth it to rerun and repost all the TZ numbers I've already put on the web, so they will stay, but I will use it in the future. It doesn't have a huge effect on fielding ratings, but might help explain the difference among pitchers of balls in play.