Best Evidence Rule (Original Document Rule)

The best evidence rule, codified in Federal Rules of Evidence 1001-1008 and more precisely called the original document rule, requires that when a party seeks to prove the contents of a writing, recording, or photograph, the original must be produced unless it is unavailable for reasons not attributable to the proponent's bad faith. The rule recognizes that copies may contain errors or alterations that only comparison with the original would reveal.

The rule applies in two situations: when a party seeks to prove the contents of a writing (because the writing itself is the legally operative document, such as a contract, deed, or will), and when a witness testifies relying on a writing rather than independent knowledge. The rule does not apply when a witness testifies from personal observation that happens to coincide with the contents of a document — only when the witness's testimony is essentially a recitation of the document's contents.

Under the Federal Rules, a duplicate — a counterpart produced by the same impression or from the same matrix, including photocopies and digital copies — is admissible to the same extent as the original unless a genuine question is raised about the original's authenticity or it would be unfair to admit the duplicate. This liberalization reflects modern recognition that high-quality copies are generally reliable and that requiring originals in routine cases would be unnecessarily burdensome.

The rule provides several exceptions for when the original is unavailable. If the original was lost or destroyed in good faith, is not obtainable by judicial process, is in the possession of an opponent who was put on notice, or relates to a collateral matter, secondary evidence (such as testimony about the document's contents or a copy) is admissible. The judge determines preliminary questions about the original's availability under Rule 104(a), while the jury decides factual disputes about the document's contents.