In baseball, an earned run is any run for which the pitcher is held accountable (i.e. the run did not score as a result of a fielding error or a passed ball). If a run is not earned, it is an unearned run. Even if a runner scores on a fielding error by the pitcher himself, it is an unearned run.
Earned runs are specially denoted because of their use in calculating a pitcher's earned run average.
In determining earned runs, the official scorer must reconstruct the inning as it would have occurred without the errors (which include catcher's interference ) and passed balls, with the benefit of the doubt always being given to the pitcher in determining which bases would have been reached by errorless play.
See also
