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 Rhode Island, an offer of proof is a procedural mechanism used during a trial when the court excludes evidence. This process allows the attorney to create a record of what the evidence would have shown, had it been admitted, by presenting it outside the jury's presence, typically after an objection has been sustained. The purpose is to preserve the issue for appeal by demonstrating how the exclusion of the evidence could have affected the outcome of the case. On the other hand, a bill of exceptions, or formal bill of exception, is a more antiquated procedure that was historically used to document objections to the exclusion of evidence for appellate review when no offer of proof was made during the trial. Modern practice, however, has largely replaced bills of exception with transcripts and other means of creating a record for appeal. It is important for attorneys to understand and utilize these procedures to ensure that a proper record is made for potential appeals regarding evidentiary rulings.