Chase Value: xChase+ and the decision cards

By Samuel Sullivan · LinkedIn

Chase rate counts how often a hitter swings at pitches outside the zone and treats every one as the same mistake. This project prices every chase in runs with Statcast data, ranks every qualified hitter, and turns the number into a one-pitch plan a coach can hand to a player.

Decision cards and the roster, every qualified hitterA card for each hitter: zone pictures by count and pitcher hand, the biggest leaks, the plan, the count check and the target. Or the roster: every hitter by team on one page, sorted by runs at stake, each name opening his card. Interactive, for every season since 2021; the view, team and season switches are on the page. The 17 noted hittersCards, plans, count checks, targets and a coach's note for the hitters the coaching reports name. The method and the evidenceHow a chase is priced, whether xChase+ repeats, what happened when hitters fixed their leaks, and the frozen predictions for 2027.

Statcast data via pybaseball. Pages are generated by the project's scripts; nothing here is edited by hand except this one.