from the no-not-nuclear-war-but-baseball dept.
Brayden King and Jerry Kim write in the NYT that a team studying more than 700,000 pitches into the strike-zone during major league baseball games found that umpires frequently made errors behind the plate about 14 percent of non-swinging pitches were called erroneously. Using pitch-location data compiled by high-speed cameras , the team found that many of those errors occurred in fairly predictable ways. For example, umpires tend to favor the home team by expanding the strike zone, calling a strike when the pitch was actually a ball 13.3 percent of the time for home team pitchers versus 12.7 percent of the time for visitors. Other errors were more surprising. For example, analysis suggests that umpires were 13 percent more likely to miss an actual strike in the bottom of the ninth inning of a tie game than in the top of the first inning, on the first pitch.
However the research team also observed that there are other errors that are not deliberate that may reflect an unconscious and biased decision-making process. In general umpires tend to make errors in ways that favor players who have established themselves at the top of the game's status hierarchy (PDF). For example, an umpire was about 16 percent more likely to erroneously call a pitch outside the zone a strike for a five-time All-Star than for a pitcher who had never appeared in an All-Star Game and an umpire was about 9 percent less likely to mistakenly call a real strike a ball for a five-time All-Star. Finally pitchers with a track record of not walking batters like Greg Maddux were much more likely to benefit from their All-Star status than similarly decorated but "wilder" pitchers like Randy Johnson.
"This season Major League Baseball is allowing its officiating crews to use instant replay to review certain critical calls, including home runs, force plays and foul balls. But the calling of the strike zone determining whether a pitch that is not swung at is a ball or a strike will still be left completely to the discretion of the officials," conclude the authors. "Technologically, Major League Baseball is in a position, thanks to its high-speed camera system, to enforce a completely accurate, uniform strike zone. The question is whether we, as fans, want our games to be fair and just, or whether we are compelled to watch the game because it mimics the real world, warts and all."