Rules of evidence

As to the rules of evidence, it is not always helpful to generalise, but it may be said that, on the whole, arbitral tribunals do not usually seek to confine themselves to following the strict rules of evidence as understood in common law jurisdictions.

Much depends on the composition of the tribunal and the agreement as to procedure and rules of evidence arrived at by the parties. Nevertheless, there is a tendency for tribunals to place an emphasis on the different weight that may be given to a piece of evidence, depending on its provenance, rather than to apply strict exclusionary rules. A tribunal will rightly be conscientious to ensure that the only evidence it takes into consideration is that which is relevant; nevertheless, an observer of an arbitration hearing is likely to identify it as being more influenced by the common law than any other legal tradition, albeit that in so many ways arbitration reflects a fusion of those traditions.

It will be for the parties to decide what rules of evidence, if any, should apply to their arbitration. It is usually good practice to agree as much detail as possible in the arbitration agreement itself. However, very often parties will only decide on the approach they wish to take to the admissibility and weight of evidence once a dispute has arisen. In the event that the parties do not come to an agreement, then it is for the arbitral tribunal to decide whether to apply strict rules of evidence on admissibility, relevance and weight and, in particular, to determine how to treat hearsay evidence and documentary evidence that may not be capable of being produced in a formal way.

As indicated above, in practice, an arbitral tribunal will look to admit into evidence all material put before it but then to make a determination as to relevance and weight. In considering the approach to evidence, it should be remembered that civil law practitioners frequently criticise international arbitration as being too common law-centric. Certainly the concept of hearsay evidence, for instance, is a common law one. An arbitral tribunal will need to consider what factors are taken into account in determining the weight that should be given to a particular piece of evidence, especially when it is, in common law terms, hearsay evidence.

As to deciding on the rules to be followed and on procedure generally, it will be recalled that article 19(1) of the Model Law makes it clear that the parties are free to agree on the procedure to be followed by the arbitral tribunal in conducting the proceedings. It is important that the parties reach such agreement whenever they are able. However, by virtue of art 19(2), where there is no such agreement the arbitral tribunal may, subject to the lex arbitri, conduct the arbitration in such manner as it considers appropriate.

In determining procedure, a tribunal will always have in mind that the proceedings, in a very real sense, belong to the parties. That is particularly the case in relation to delays in filing pleadings and submissions, and in complying with time scales generally. A tribunal may penalise a party by censure and in costs, but tribunals understandably are anxious to keep the goodwill of the parties and to enable proceedings to remain the parties’ private set of proceedings (to the extent that the applicable law and rules allow).

Burden of proof and standard of proof

The general principle is that the burden of proof in respect of any allegation rests upon the party making that allegation. As to the standard of proof, it should be taken that the standard of proof is the balance of probabilities; in other words, a 51% test. However, given that civil law practitioners are not always comfortable in describing the standard of proof in terms which essentially derive from the common law, the phrase balance of probabilities should be used cautiously. In addition, it is a reality of the practice of international arbitration that depending on the nature of the allegation being made and its ramifications, a tribunal may be inclined to look very carefully at the extent and weight of the evidence it requires before the burden is satisfied.