Earned Run

In baseball, an earned run is any run for which the pitcher is held accountable (i.e., the run scored as a result of normal pitching, and not due to a fielding error or a passed ball). Any runner(s) who tags his base and reaches home plate is scored against the pitcher as an earned run(s). An error made by the pitcher in fielding at his position is counted the same as an error by any other player.

Earned runs are specially denoted because of their use in calculating a pitcher's earned run average – the number of earned runs allowed per 9 innings (regulation game) pitched. Earned runs stem from the theory that the pitcher has sole responsibility to earn strikes against opposing batter(s) until at least three batters are retired in each inning of play, and nine innings (a complete game) are pitched.

To determine whether a run is earned, the official scorer must reconstruct the inning as it would have occurred without the errors (for purposes of this rule, the "errors" also include passed balls). The benefit of the doubt is always given to the pitcher in determining which bases would have been reached by errorless play.

If no errors and no passed balls occur during the inning, all runs scored are automatically earned (assigned responsible to the pitcher). In a few cases, an error can be rendered harmless while the inning is still going on. For example, a runner on first base advances to second on a passed ball. The next batter walks. Since the runner would now have been at second anyway, the passed ball no longer has any impact on the earned/unearned calculation.