The best evidence rule is pretty much exactly what it sounds like: a rule of evidence requiring the “best” evidence of something be admitted at trial or during a hearing. In most cases, this means the original of a document or object (or a verifiably accurate copy) must be the one used in court, unless it has been lost or destroyed.
The best evidence rule has been part of U.S. law since colonial times. In the eighteenth century, a British court described the rule as barring all evidence unless it was “the best that the nature of the case will allow.” Before the era of reliable photocopiers and drag-and-drop file-sharing, the best evidence rule helped to reduce the number of error-ridden copies or downright forgeries in court by requiring that the original document, not a copy handwritten by a clerk, be used in court.
Today, litigants generally accept that a photocopy or scanned electronic version of an original document is not likely to come with major errors or fraudulent changes from the original. At worst, a copy or scan might be hard to read. Therefore, the best evidence rule does not typically come up when photocopies of a document are used in court, unless one of the parties suspects that the copies have been altered through fraud or by mistake.
The best evidence rule affects both real evidence, or physical evidence, and documentary evidence, or recordings of information used as evidence. In both cases, the “real McCoy” – a defective object in a products liability case or the original recording from a security camera, for example – is generally preferred over a copy of documentary evidence or a photograph, diagram, or model of real evidence.
This is not always the case, however. Sometimes, documentary evidence is acceptable because the actual object was destroyed or simply cannot be brought into a courtroom. For example, a 2011 issue of the ABA Journal discussed a personal injury case in which a railroad employee was injured by a defective locomotive. The employee’s attorneys tried to have photographs of the locomotive, which clearly showed the defects, admitted into evidence. The opposing attorney objected, however, citing the best evidence rule: the locomotive itself was the best evidence that the locomotive was defective. Therefore, the opposing attorney argued, the actual locomotive should be admitted into evidence – not the photographs of it.
Not surprisingly, the opposing attorney lost this argument. Even though it makes legal sense – the best evidence rule does require the actual object when you can get it – it doesn’t make real-world sense. Bringing a full-size locomotive into court would be nearly impossible, so even if the defective locomotive is still available, the best evidence rule would not require the plaintiff to bring it into court when good photographs were available to show the jury as well.
In some cases, the best evidence rule becomes an issue due to spoliation. Spoliation occurs when one party intentionally or negligently destroys or alters evidence, or something the party should reasonably understand might be evidence in an upcoming court case. When spoliation results in the destruction or altering of a piece of evidence, the best evidence rule may allow a copy, photograph, or “less than best” alternative to be used, because the original is no longer intact or accurate. In these situations, the court will usually also give a jury instruction that tells jurors they’re allowed to assume that the original would have been harmful to the person who spoiled it.