Editing Official scorer (section)

====Unearned runs====
Earned runs are runs that are directly attributable to a pitcher's efforts without a lapse by the defense. An [[unearned run]] does not adversely impact a pitcher's [[earned run average]] (ERA), and is only possible when an error (including catcher's [[Interference (baseball)|interference]]) or a [[passed ball]] occurs earlier in the inning. Unearned runs are primarily discussed in rule 10.16 and often require a judgment call by the official scorer.<ref name="bbskUER">Wirkmaa, pp.185–217</ref>

At the conclusion of an inning during which runs are scored after an error or passed ball, the official scorer attempts to recreate the events of the inning without the errors or passed balls. If in the official scorer's opinion a run would not have scored without the defensive lapses, then the run is unearned. If the scorer believes that a run would have scored anyway, the run is earned and charged to the pitcher. In one basic example, if the first batter reaches by an error, the second batter hits a [[home run]], and the next three batters [[Strikeout|strike out]], then one of the two runs scored was unearned. There are rules and restrictions which govern this general guideline.<ref name="bbskUER" />

When reconstructing an inning without errors or passed balls:

* Potential outs that were not recorded because of an error are presumed to be an out when the inning is reconstructed by the official scorer.
* [[Intentional base on balls|Intentional walks]] which were issued are still presumed to be [[Base on balls|walks]].
* Runs that are scored after what should have been the third out are automatically considered to be unearned.
* When the batter is given first base because of catcher's interference or [[Obstruction (baseball)|obstruction]], the official scorer does not presume that an out would have been recorded on that runner, but if that runner later scores the run is unearned.
* A run scored by a runner who advances due to an error or passed ball is unearned, unless it would not have made a difference in the reconstruction of the inning.<ref name="bbskUER" />

Most of the above rules are straightforward, but some judgment is required by the official scorer when a baserunner advances due to a defensive lapse and later scores. In this situation, the official scorer must decide what would have happened if the runner had not advanced. This is often an easy decision, but it can occasionally be difficult. In one difficult example with a runner on first and two outs, the batter hits a single but a defensive error allows an advance by the lead runner from second to third, and a soft run-scoring single is hit followed by an out. In that situation, the offense "should" have had runners on first and second with 2 outs when the run-scoring single was hit. Since the next batter was put out, the official scorer must decide based on the hit, the speed of the baserunner, and the positioning of the defense whether the runner would have been able to score from second in the reconstruction of the inning without the error.<ref name="bbskUER" />