An analysis of nearly 4 million pitches shows just how many mistakes umpires make

Sign of times: MLB gives OK to electronic pitch calling

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MLB Umpires Missed 34,294 Pitch Calls in 2018. Time for Robo-umps?, BU Today

Analysis of nearly 4M pitches shows how many mistakes umpires make - Boston Business Journal

Major league 11 seasons · Analysis of 4 million ball pitch data and analysis of how well the referee judged - GIGAZINE

Grading MLB umpires: Meet the humans behind the Twitter bots that track balls and strikes - The Athletic

The Robot Umpire: The technology is there, it makes no sense not to use it

Can someone explain to me how angel hernandez is an umpire?? : r/baseball

Best of BP: The Philosophy of Robot Umps and Hit By Pitches - Baseball ProspectusBaseball Prospectus

Analysis of nearly 4M pitches shows how many mistakes umpires make - Boston Business Journal

MLB home plate umpires make incorrect calls at least 20% of the time

Why doesn't the MLB use technology to call balls and strikes when it's much more accurate than umpires? - Quora