IV. Taking of Evidence
Unless the parties have agreed upon a detailed set of rules for the taking of evidence, the arbitral tribunal usually has a broad discretion in the way it conducts the taking of evidence. If one of the parties comes from a common law legal system and the other party has its seat in a civil law country, the arbitral tribunal may use this flexibility to find a compromise between the differences in the taking of evidence of both judicial systems.
Whereas parties in common law systems usually can make use of a pre-trial discovery (meaning that the parties may request relevant information and documents from the opposing party in order to “discover” facts to rely a case upon), parties in civil procedures in most civil law countries can generally obtain a document in the possession of the other party only if it is specifically described to the court and if it is substantiated that it is of relevance for the alleged fact. Moreover, while under most common law procedures witnesses can be directly or cross-examined by party representatives, under most civil law systems only the judge will ask questions to a witness. Furthermore, common law systems tend to give witness testimony far more weight than is usual in civil law systems. Other major differences concern whether expert witnesses are appointed by the parties (typical of the common law approach) or by the arbitral tribunal (typical of the civil law approach), how legal arguments are presented at a hearing (common lawyers usually will rather concentrate on only the key points whereas civil lawyers will rather offer to elaborate on any of his pleading points in detail) and on the way how persuasive authority is used (while common lawyers rather rely on court judgments with a similar set of facts, civil lawyers will rely on many statements published by scholars).
To bridge these gaps, the International Bar Association has established the IBA Rules on the Taking of Evidence in International Commercial Arbitration, which are often agreed upon by the parties for that purpose and which are regarded as non-binding guidelines by many arbitral tribunals in cases where the parties have not agreed upon their application.
Another important difference to the power of a state court is that the arbitral tribunal itself will usually have no coercive power to compel a witness. Yet, depending on the lex loci arbitri, the arbitral tribunal may seek the assistance of a local state court.