Who Is Responsible For A Called Strike?

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Authors

Joe Rosales
Scott Spratt

Abstract

Abstract: The purpose of this paper is to introduce a new methodology for quantifying what is commonly referred to as “pitch framing,” in which we attempt to divide the credit for whether a pitch is called a ball or strike among the catcher, the pitcher, the batter, and the umpire involved. We call our system Strike Zone Plus/Minus, and it is unique from other pitch framing methodologies in two ways. First, we treat pitchers, batters, and umpires as independent actors in the system rather than treating them as variables to adjust the catcher's performance by. Second, we use Baseball Info Solutions data on where the catcher sets his target for the pitch, allowing us to incorporate the pitcher's command (how close he comes to hitting the target) into our system. Our results show that we are successfully measuring the abilities of each participant independently of each other and that we are reliably measuring a consistent pitch framing skill. Strike Zone Plus/Minus produces results that are more comprehensive and in some cases radically different than publicly available framing methodologies, which will have many implications. The most direct one will be the valuation of catchers in the free agent market.