28 USC Appendix Rule 61 - Harmless Error

Unless justice requires otherwise, no error in admitting or excluding evidenceor any other error by the court or a partyis ground for granting a new trial, for setting aside a verdict, or for vacating, modifying, or otherwise disturbing a judgment or order. At every stage of the proceeding, the court must disregard all errors and defects that do not affect any partys substantial rights.