Short answer. Not automatically. Rule 51, Section 6 bars a new trial or reversal for an evidentiary or procedural error unless refusing to act would be inconsistent with substantial justice, and requires the court to disregard any error that does not affect the parties' substantial rights.
What the law says
No error in either the admission or the exclusion of evidence and no error or defect in any ruling or order or in anything done or omitted by the trial court or by any of the parties is ground for granting a new trial or for setting aside, modifying, or otherwise disturbing a judgment or order, unless refusal to take such action appears to the court inconsistent with substantial justice.
Rule 51, Section 6 — Harmless error. Read the full provision →
What the law says
The court at every stage of the proceeding must disregard any error or defect which does not affect the substantial rights of the parties.
Rule 51, Section 6 — Harmless error. Read the full provision →
The harmless error rule
Section 6 protects judgments from being upset over every procedural misstep. No error in either the admission or the exclusion of evidence and no error or defect in any ruling or order or in anything done or omitted by the trial court or by any of the parties is ground for granting a new trial or for setting aside, modifying, or otherwise disturbing a judgment or order, unless refusal to take such action appears to the court inconsistent with substantial justice.
The substantial rights test
The section adds an affirmative duty for the appellate court, not just a limitation on when relief is available: the court at every stage of the proceeding must disregard any error or defect which does not affect the substantial rights of the parties. An error that made no real difference to the outcome or fairness of the case is to be set aside as inconsequential.
Why this matters for how appeals are argued
An appellant relying on a trial court error needs to show more than that a mistake occurred — the error has to be tied to substantial justice or to the parties' substantial rights being affected. An evidentiary slip that had no real bearing on the outcome, however technically wrong, will not by itself unravel the judgment under this rule, no matter how clearly the record shows the trial court got the ruling wrong.
What kind of showing actually succeeds
An appellant who wants to invoke this rule effectively needs to connect the specific error to a concrete consequence: evidence that, if properly admitted or excluded, would plausibly have changed the result, or a procedural defect that deprived a party of a genuine opportunity to be heard. A bare list of technical missteps in the trial court's rulings, without explaining how each one actually affected the outcome or fairness of the proceeding, gives the Court of Appeals little basis to disturb the judgment.
Related provisions
- Rule 51, Section 6 — Harmless error
- Rule 51, Section 8 — Questions that may be decided
- Rule 51, Section 4 — Disposition of a case