An offer of proof—also known as an informal bill of exception—is a procedure available during trial for the presentation of evidence the trial court has excluded. An offer of proof is made outside of the jury’s presence and often after the judge has sustained an objection to the admissibility of the evidence.

A bill of exception—also known as a formal bill of exception—is a procedure that allows a party to complain on appeal about evidence that would not otherwise appear in the trial record (because there was no offer of proof made at trial) by detailing the evidence (testimony, etc.) that would have been offered if the trial court had allowed it.

In Virginia, an offer of proof is a procedural mechanism used during a trial when the court excludes evidence. This process allows the party attempting to introduce the evidence to make a record of what the evidence would have shown, had it been admitted. This is done outside the presence of the jury and typically occurs after an objection to the evidence has been sustained by the judge. The purpose of an offer of proof is to preserve the record for appellate review, providing an appellate court with a clear understanding of the nature of the excluded evidence and the context in which it was offered. On the other hand, a formal bill of exception in Virginia is a written statement by the judge detailing the evidence that a party claims was erroneously excluded. This is used when no offer of proof was made at trial, and it serves to inform the appellate court of the specifics regarding the excluded evidence. Both procedures are essential for ensuring that a party's rights are protected on appeal, particularly with respect to evidentiary rulings made during the trial.