Most commercial arbitrations involve documents because they invariably concern written agreements that, among other things, commit the parties to resolve their disputes in arbitration. But witnesses are also needed to present and defend a case because they can fill in what a contract does not cover, including the context in which the contract was entered into and performance under it.
Although witnesses present their evidence in hearings orally, it has become common practice in international arbitration for their initial, or direct, testimony to be put forward in written form through witness statements. These statements, often detailed because they set forth what would otherwise be presented in direct oral testimony, are made available to the parties and the tribunal (usually three arbitrators) as part of the parties’ prehearing submissions in which they also make presentations concerning the facts of the case, the legal issues and their positions on them.
One result of this practice is that the presentation of evidence in hearings in international arbitration upends the order in which documents and witnesses are presented in traditional American court proceedings, where documents are admitted in evidence only after they have been identified and authenticated at trial by witnesses. In contrast, in international arbitration, the authenticity of documents is ordinarily accepted when they are presented prior to the hearing unless a party then questions their authenticity, enabling the tribunal to deal with such issues before the hearing.