Harmless error is a law term found in the extensive case law, state statutes as well as Federal Rules of Criminal Procedure. It is impossible to conduct all criminal trails totally error free. These can be applied to the ordinary evidential mistakes that are committed during a trail. The rule is present with all the 50 states and federal courts.
The ruling given by a trail judge that was given as a clear mistake, but the appellate court does not find anything to justify or reverse or modify the lower court's judgment at trail is called harmless error. An evidential context will help one understand this.
These errors include technical errors that have no bearing to the outcome of the trail. They also may include following a curative instruction like allowing a testimony to take place, then ordering to stricken it and admonishing the jury to ignore it. Most of the time, appeals court find the error by the judge to be harmless, as the appealing party would not have won the trail even if this error had occurred.
The standard is based on the finding that the error is not significantly prejudicial to the appellant. This error has had little or no effect to the outcome of the case. The appellant courts sent their opinion on a two-step analysis of harmless error standard. The first step involves analysis if the judge did indeed carry out an error. While the second step includes determining if this was actually harmless. In some cases, appeals courts only analyze if the alleged error was indeed harmless, and do not decide whether an error was actually committed.
According to a Federal Rule of Criminal Procedure 52(a), 'Any error, defect, irregularity or variance which does not affect substantial rights shall be disregarded.' Therefore, if the error committed does not affect the outcome of the trail, it is termed as harmless error. A criminal defense lawyer will help one understand the rule much better in an individual case.