https://techcrunch.com/2019/04/08/a-new-study-of-mlb-pitch-calls-makes-a-strong-case-for-robotic-umpires/

Boston University grad students analyzed more than four million pitches from 11 seasons of Major League Baseball (2008-2018), and the findings aren’t great for human umpires. According to the study, umps made 34,294 incorrect ball and strike calls in 2018. That works out to 14 blown calls per game and 1.6 per inning.

It’s not a huge number, compared to the 162 games each of the league’s 30 teams play in a given regular season, but it’s enough to give pause — and to confirm the suspicions that many irate spectators have had for years.