Earned run

In baseball, an earned run is any run that was fully enabled by the offensive team's production in the face of competent play from the defensive team. Conversely, an unearned run is a run that would not have been scored without the aid of an error or a passed ball committed by the defense; it is "unearned" in that it was, in a sense, "given away" by the defensive team.

Earned and unearned runs count equally toward the game score; the difference is purely statistical. Both total runs and earned runs are tabulated as part of a pitcher's statistics, but earned runs are specially denoted because of their use in calculating a pitcher's earned run average (ERA), the number of earned runs allowed by the pitcher per nine innings pitched (i.e., averaged over a regulation game). Thus, in effect, the pitcher is held personally accountable for earned runs, while the responsibility for unearned runs is shared with the rest of the team.

To determine whether a run is earned, the official scorer must reconstruct the inning as it would have occurred without errors or passed balls.

If no errors and no passed balls occur during the inning, all runs scored are automatically earned (assigned responsible to the pitcher(s) who allowed each runner to reach base). Also, in some cases, an error can be rendered harmless as the inning progresses. For example, a runner on first base advances to second on a passed ball and the next batter walks. Since the runner would now have been at second anyway, the passed ball no longer has any effect on the earned/unearned calculation. On the other hand, a batter/runner may make his entire circuit around the bases without the aid of an error, yet the run would be counted as unearned if an error prevented the third out from being made before he crossed the plate to score.

An error made by the pitcher in fielding at his position is counted the same as an error by any other player.

A run is counted as unearned when:

While the inning is still being played, the second and the second-last scenario can cause a temporary situation where a run has already scored, but its earned/unearned status is not yet certain. Under the last circumstance, for example, with two outs, a runner on third base scores on a passed ball. For the time being, the run is unearned since the runner should still be at third. If the batter strikes out to end the inning, it will stay that way. If the batter gets a base hit, which would have scored the runner anyway, the run now becomes earned.

Under the second circumstance, if there are runners on base and a batter hits a foul fly ball that is dropped, and then bats in the runners on base through a base hit (including a home run), the runs are unearned for the time being, as the runners should not have advanced. If the results of the remaining at-bats in the inning would not have scored the runners, the runs remain unearned. However, if results of subsequent at-bats would have scored the runs anyway, the runs would count as earned, unless they only would have scored as a result of a subsequent error or passed ball.