https://thenextweb.com/science/2019/04/12/baseball-stat-heads-tracked-4m-pitches-to-prove-that-umpires-really-are-blind/

It’s been less than a month since Opening Day. The 2019 Major League Baseball (MLB), like more than a century of professional baseball seasons before it, has already seen its share of controversial calls by the game’s most hated employees: umpires.

For the home plate umpire, life can be a bit tricky. He stands inches behind the catcher, zeroing in on another man, the pitcher, standing 60 feet, 6 inches from home plate. In a fraction of a second, he’s responsible for determining whether a pitch traveling at speeds often exceeding one hundred miles per hour lands within an invisible rectangle that’s, roughly, located between the bottom of the numbers on a jersey — though that’s really more like the top of their belt, these days — and the knees. And as anyone who’s ever watched a baseball game can attest, they’re not infallible.