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 New Hampshire, 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 the evidence they sought to introduce, which is done outside the presence of the jury, typically after an objection has been sustained. The purpose of an offer of proof is to preserve the issue for appeal by demonstrating what the evidence would have shown, allowing appellate courts to review the trial court's decision to exclude it. On the other hand, a bill of exception in New Hampshire is a more formalized process that is used to preserve a record for appellate review when no offer of proof was made at trial. It details the evidence that would have been presented, allowing the appellate court to consider whether the exclusion of such evidence was erroneous and whether it affected the outcome of the trial. Both procedures are essential for ensuring that a party's right to appeal is protected regarding evidentiary rulings made during the trial.