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Baseball Stadium

Founded By
Baseball Nerds


UmpScores was born out of academic research conducted at Boston University and rooted in a mission to create transparency and performance measurement of MLB home plate umpires. The Team at UmpScores consists of baseball nerds, quants, programmers, and fans with a single desire to improve the game of baseball.

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Our Story

In April 2019, we published a widely cited report analyzing over 4 million ball-strike calls over 11 seasons (2008-2018).  The main findings in that report were that accuracy rates were much lower than reported by MLB, younger umpires tended to perform better than their older peers, and post season assignments tended to go to lower performing umpires. We also provided a follow-up report in November 2019 highlighting the fact that bad umpiring impacted the World Series.  In updating our original study, a report in 2021 was published that highlighted the improvement of umpire performance but also showcasing that many senior umpires continued to lag behind their younger counterparts in performance while still receive top assignments to playoff games.

Since 2019, the UmpScores team has provided umpire stats and analysis directly to you with focus on providing accurate and transparent season long metrics and individual game performance measurments. We focus on three main measurements of umpire performance: umpire accuracy, measured by our Bad Call Ratio (BCR); umpire precision, measured by our consistency metric; and performance in critical situations during games, which we highlight on each game scorecard. For a better understanding how we calculate each of these metrics, check out our methodology section.

Download the free UmpScores App to get season by season statistics and biographies of all MLB umpires, visit us on or follow us on social media for daily reports on each umpire’s performance in every game of the year.

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