NEW YORK—It is a historic year for Major League Baseball (MLB) as the organization introduces its expanded use of instant replay, allowing umpires to review home run calls, forced plays, foul balls and more. But the one decision still left fully in the hands of umpires is the calling of the strike zone. Should the rules be expanded for review of those calls? A new study from Columbia Business School says reviewing strike zone calls may be the one call All-Star pitchers would loathe. 

The study reviewed nearly 800,000 pitches from roughly 5,000 games in 2008 and 2009 and compared these pitches to the MLB’s official strike zone. The researchers found that umpires grant a larger and more generous strike zone to All-Star pitchers, and were also less likely to miss pitches that were in the official strike zone for these pitchers.

“All-Star pitchers should thank their lucky stars that instant reply does not cover ball-strike calls this year,” said Professor Jerry Kim, assistant professor at Columbia Business School and author of the research. “Our empirical evidence proves that most of the wrong calls during at-bat scenarios are in the star’s favor. The Clayton Kerhsaws, and Justin Verlanders of the world have more to lose than the average Joe pitcher.”

The research, titled “Seeing Stars: Matthew Effect and Status Bias in Major League Baseball Umpiring” is co-authored by Brayden King, associate professor of management and organizations at the Kellogg School of Management, and will soon be published in the academic journal Management Science.

The research revealed additional startling takeaways regarding umpire bias:

• Umpires make a mistake on around 14% of all called pitches by either calling a pitch outside the strike zone a strike, or calling a pitch inside the zone a ball.
• An umpire is about 16% more likely to erroneously call a pitch outside the strike zone for a five-time All-Star pitcher than he is for a player who has never gone to an All-Star game.
• An umpire is about 9% less likely to mistakenly call a real strike a ball for a five-time All-Star.
• These mistakes happen at a higher rate when the stakes are high (i.e., important game situations).
• All-Star batters also receive the benefit of the doubt from umpires, but the effect was smaller than for pitchers.

Even more surprising is what the research identifies is the intriguing source of distraction for umpires whose job is to ensure the integrity of the game is sound in an objective, unbiased way: the umpires can not help but be ‘star-struck’ over the All-Star pitchers.

Kim and King found that umpires, just like all humans are hard wired to place rankings on people and use that information to make decisions. Time and time again, the umpire’s subconscious mind was influenced by status and reputation causing what the research refer to as the ‘Matthew Effect,’ or an accumulated advantage.

“Ultimately, non All-Star players, with good performance, find themselves handicapped by comparison, while All-Star players may find themselves rewarded even when they are undeserving,” said Kim.

The Research

Kim and King reviewed nearly 800,000 pitches using the MLB’s four high-speed cameras installed in each MLB stadium. The cameras take 25 snapshots of each pitch, capturing the speed and spin rate from different angles, and recording where in the strike zone the pitch lands.

This data, collected from almost 5,000 games in 2008 and 2009, gave the researchers exact measures of quality that they could compare to umpires’ actual calls, which they compared with player stats and All-Star Ballot standing. The two used the MLB’s official strike zone images, alongside the exact coordinates from the videos to determine whether the pitch was an actual ball or strike.

In order to understand the conditions under which an umpire makes mistakes, the researchers looked at pitches where the ball was outside of that strike zone, but the umpire called a strike or conversely when the pitch was inside of that strike zone but the umpire called a ball.

To learn more about the cutting-edge research being conducted at Columbia Business School, please visit www.gsb.columbia.edu.

To learn more about Columbia Business School's Executive Education, please visit  www.gsb.columbia.edu/execed.

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About Columbia Business School

Columbia Business School is the only world-class, Ivy League business school that delivers a learning experience where academic excellence meets with real-time exposure to the pulse of global business. Led by Dean Glenn Hubbard, the School’s transformative curriculum bridges academic theory with unparalleled exposure to real-world business practice, equipping students with an entrepreneurial mindset that allows them to recognize, capture, and create opportunity in any business environment. The thought leadership of the School’s faculty and staff, combined with the accomplishments of its distinguished alumni and position in the center of global business, means that the School’s efforts have an immediate, measurable impact on the forces shaping business every day. To learn more about Columbia Business School’s position at the very center of business, please visit www.gsb.columbia.edu.

About Professor Jerry Kim

Professor Kim studies status competition in market and non-market (i.e., government and regulatory) settings. One stream of research investigates how status influences the strategic outcomes for life sciences firms, from alliance formation to FDA approval speed for new drugs. Another stream focuses on how status considerations bias the decision-making process of individuals and organizations in a wide range of contexts, including executive compensation, baseball umpiring, and patient treatment at large hospitals. His work has been published in journals such as the Academy of Management Journal, Strategic Organization, and Research Policy, and profiled in publications such as The Economist. Professor Kim teaches the Strategy Formulation course in the MBA and Executive MBA programs, and has received multiple awards for teaching excellence. Graduating MBA students selected him as the winner of the Singhvi Prize for Scholarship in the Classroom in 2011 for his dedication to teaching and ability to communicate knowledge. He also received the Dean’s Award for Teaching Excellence in 2008.