Official scorer

In the game of baseball, the official scorer is a person appointed by the league to record the events on the field, and to send the official scoring record of the game back to the league offices. In addition to recording the events on the field such as the outcome of each plate appearance and the circumstances of any baserunner's advance around the bases, the official scorer is also charged with making judgment calls that do not affect the progress or outcome of the game. Judgment calls are primarily made about errors, unearned runs, fielder's choice, the value of hits in certain situations, and wild pitches, all of which are included in the record compiled. This record is used to compile statistics for each player and team. A box score is a summary of the official scorer's game record.

Newspaper writers initially performed this function in the early days of Major League Baseball (MLB). As the importance of baseball player statistics increased, teams began to pressure writer-scorers for favorable scoring decisions for their players in games played at home stadiums, and a home team scoring bias was perceived by many coaches, players, and writers. Controversies related to perceived bias or errors in scoring have led to questions about important baseball records, including several no-hitters and Joe DiMaggio's 56-game hitting streak of 1941. By 1979, many major newspapers decided to ban their writers from scoring baseball games due to conflict-of-interest concerns, and in 1980 MLB began to hire independent official scorers.

Since 1980, some reforms have been suggested to improve the performance of official scorers. In 2001, MLB formed a scoring committee to review their performance, and by 2008 the committee was given the authority to overturn scoring decisions. This authority was used by the scoring committee three times during the 2009 season. In 2006, an academic study seemed to confirm the historical existence of a home-team bias in scoring decisions, but this measurable bias decreased after 1979.

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