Parties engaged in arbitration are, broadly speaking, free to decide how evidence is to be taken and handled during the arbitral process. The parties can tailor the rules of evidence to meet the particular requirements of their dispute, rather than having unfamiliar or less efficient rules forced upon them by a court. This flexibility is one of many advantages that arbitration has over court litigation.

Agreeing what the rules of evidence will be in an arbitration can be difficult. If the Tribunal and the parties' respective legal representatives come from different legal backgrounds, they may have differing and sometimes contradictory expectations as to how evidence is to be presented and adduced. This is often the case in arbitrations in the Middle East where common law lawyers from the West and regionally-trained civil law lawyers may be involved in the same case. This presents a risk that time and money will be wasted deciding and arguing over what rules of evidence to apply.