The order of presentation at the hearing must be as agreed by the parties or as determined by the neutral chairperson. The neutral chairperson is the judge of the relevancy of the evidence. All evidence must be taken in the presence of all parties, unless a party is absent in default or has waived its right to be present. Each documentary exhibit must be submitted to the neutral chairperson and copies must be provided to the partisan arbitrators and to the other parties. The exhibits must be retained by the neutral chairperson until an agreement has been signed or until any judicial review proceedings have concluded, after which they may be disposed of as agreed by the parties or as ordered by the neutral chairperson. The neutral chairperson has authority to administer oaths, to require the attendance of witnesses, and to require the production of documents that the chairperson may deem to be material.