Home plate umpires are getting better. Will that hold off the robots?

Boston University business school professor Mark Williams maintains an umpiring database, which grades ball- and strike-calling accuracy. Williams, a lifelong baseball fan, decided to start grading umps after getting frustrated by missed calls during the Red Sox’ 2018 World Series run and became skeptical of MLB’s accuracy claims. His data goes back to 2010, early in the pitch-tracking era.

Ball-strike accuracy was 7% better in April compared to April 2022. Williams’ bad call ratio metric - the percentage of strikes called outside of the strike zone’s confines and balls called within it - was 6.7% for the month. If it held, it would represent a record, bettering last year’s 7.2% for April, which was also the mark for the entire season.

If this April’s metric is extrapolated across the entire season, it’ll represent better than a 50% improvement from 2010, when umpires missed 14.3% of calls.