Chapter 35 - Expert Evidence - Handbook on International Commercial Arbitration - Second Edition
Many references may raise issues that either cannot sensibly be resolved without expert testimony or the determination of which are greatly assisted by expert testimony. In consequence, and in addition to documentary evidence and witness statements, it is common practice to adduce the evidence of experts. Expectations as to the manner in which experts are selected, appointed, and give evidence can, however, vary greatly.
To many the notion of expert evidence in arbitration is an anathema as the arbitral tribunal are appointed for their expertise. This is indeed often the case for trade arbitrations with disputes on, say, quality. The preponderance of lawyers as arbitrators necessitates that technical evidence is given by experts. This results in expert evidence on, among others, engineering, science, trade practice, foreign law and accounting. The issues upon which expert evidence is adduced are therefore not on whether something occurred but why or how it occurred or on the consequences of a breach of contract, such as the damages naturally arising flowing from the breach. The common feature is that the evidence is of opinion. Necessarily, there can be a range of opinion, typically with a narrower range within which reasonable professionals could quite properly differ. This makes the function of the tribunal all the more difficult.
Historically, it was often said that expert evidence is precluded on the ultimate issue but that rule is now abolished in most common law countries. Provided a tribunal does not abrogate its responsibility and effectively delegate the decision-making process to the expert, it is quite proper to adduce expert evidence and, if two or more experts opine on the same issue, it is the function of the tribunal, using its own expertise or experience as necessary, to prefer the opinions of one expert over another (or prefer parts of the opinions of one and parts of the opinions of the other).