7.01 It is generally recognised that arbitrators have great freedom to determine the admissibility of evidence and weigh its probative value in the light of the circumstances of the case and arguments of the parties. The deference given to arbitrators notwithstanding, there remain outer limits on a tribunal’s authority to weigh and admit evidence as defined by principles of due process. The initial portion of this chapter considers the general grant of discretion as set forth in article 9.1 of the IBA Rules, with regard to due process issues, and also discusses commonly accepted principles utilised by tribunals in the weighing of evidence.