refers to violations of procedural rules or constitution
al guarantees that are not prejudicial
, i.e. do not affect the ultimate outcome of the case.
Federal Rules of Civil Procedure
Rule 61. Harmless Error
The court at every stage of the proceeding must disregard any error or defect in the proceeding which does not affect the substantial rights of the parties.
Federal Rules of Criminal Procedure
Rule 52(a). Harmless and Plain Error.
Harmless error. Any error, defect, irregularity, or variance that does not affect substantial rights must be disregarded.
If an appellant
shows that the lower court or agency committed error
during the course of the proceedings below, the appellant is entitled to relief
) to correct the error, unless the appellee
shows that the error is harmless.