Art. 921 Matters not grounds for reversal

If you're convicted of a crime and you appeal, the appeals court won't automatically overturn your case just because something went wrong during the trial. Small mistakes happen in almost every trial. Maybe a piece of paperwork had the wrong date, or a lawyer misspoke, or a minor procedure wasn't followed exactly right. None of these things by themselves will get a conviction thrown out.

The key question the appeals court asks is whether the mistake actually hurt your case in a real way. If an error didn't change the outcome and didn't harm your ability to get a fair trial, the court will let the conviction stand even though something technically went wrong. This is sometimes called "harmless error."

For this rule to matter, the mistake has to be serious enough that it affected your substantial rights, meaning it likely changed how the jury decided the case or took away a real chance you had to defend yourself. Small clerical errors, technical slip-ups, or minor rule violations usually don't meet that bar. This rule exists so that convictions aren't overturned over technicalities that didn't actually change the result of the trial.