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 South Carolina, an offer of proof is a procedural mechanism used during a trial to create a record of evidence that the trial court has excluded. This is done outside the presence of the jury, typically after an objection to the evidence has been sustained by the judge. The purpose of an offer of proof is to preserve the excluded evidence for appellate review, by demonstrating what the evidence would have shown and why it should have been admitted. On the other hand, a bill of exceptions, or formal bill of exception, is a written statement by the judge detailing the evidence that was not allowed to be presented during the trial. This is used to preserve a legal question for appeal when no offer of proof was made at trial. The bill of exceptions must be signed by the judge and is then included in the record on appeal to show the appellate court the evidence that was excluded and the context of its exclusion. Both procedures are important for ensuring that a party's right to appeal is protected, particularly with respect to evidentiary rulings made during the trial.