In baseball, a run scored without an out is called an unearned run. This typically occurs when the opposing team's defense commits an error, allowing a baserunner to score without earning the run through conventional hitting. The distinction between earned and unearned runs is important for evaluating a pitcher's performance, as it reflects how many runs resulted from errors versus legitimate hits. This statistic can influence a player's ERA (earned run average) and overall effectiveness on the mound.