Catcher's ERA (CERA) in

baseball statistics Baseball statistics play an important role in evaluating the progress of a player or team. Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itsel ...

is the

earned run average In baseball statistics, earned run average (ERA) is the average of earned runs allowed by a pitcher per nine innings pitched (i.e. the traditional length of a game). It is determined by dividing the number of earned runs allowed by the number ...

of the

pitcher In baseball, the pitcher is the player who throws ("pitches") the baseball from the pitcher's mound toward the catcher to begin each play, with the goal of retiring a batter, who attempts to either make contact with the pitched ball or draw ...

s pitching when the

catcher Catcher is a Baseball positions, position in baseball and softball. When a Batter (baseball), batter takes their at bat, turn to hit, the catcher crouches behind home plate, in front of the (home plate, home) Umpire (baseball), umpire, and recei ...

in question is catching. Its primary purpose is to measure a catcher's game-calling, rather than his effect on the opposing team's running game. Craig Wright first described the concept of CERA in his 1989 book ''The Diamond Appraised''. With it, Wright developed a method of determining a catcher's effect on a team's pitching staff by comparing pitchers' performance when playing with different catchers.

Baseball Prospectus Baseball Prospectus (BP) is an organization that publishes a website, BaseballProspectus.com, devoted to the sabermetric analysis of baseball. BP has a staff of regular columnists and provides advanced statistics as well as player and team perf ...

writer

Keith Woolner Keith Woolner (born c. 1968) is an author for Baseball Prospectus and is the creator of the statistic Value Over Replacement Player (VORP). VORP is acknowledged by the sabermetrics community as one of the key concepts in the analysis of a player's p ...

has written that "catcher game-calling isn't a statistically significant skill" after doing statistical analysis of catcher performance.

Sabermetrician Sabermetrics, or originally SABRmetrics, is the empirical analysis of baseball, especially baseball statistics that measure in-game activity. Sabermetricians collect and summarize the relevant data from this in-game activity to answer specific ques ...

Bill James George William James (born October 5, 1949) is an American baseball writer, historian, and statistician whose work has been widely influential. Since 1977, James has written more than two dozen books devoted to baseball history and statistics. ...

also performed research into CERA, finding that while it is possible that catchers may have a significant effect on a pitching staff, there is too much yearly variation in CERA for it to be a reliable indicator of ability. James used simulations of catchers with assigned defensive values to directly compare CERAs, which influenced Woolner to perform similar simulations but instead using weighted events to calculate pitchers' runs per plate appearance. Through this, Woolner concluded that even if catchers do have an effect on pitchers' abilities to prevent runs, it is undetectable and thus has no practical usage. He also stated that "the hypothesis most consistent with the available facts appears to be that catchers do not have a significant effect on pitcher performance".

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See also