Ill. Admin. Code tit. 56 § 110.110
All proceedings conducted by the arbitrator shall be in conformity with the contractual obligations of the parties. The arbitrator must conduct all proceedings in conformity with Section 110.40(b). The conduct of the arbitration proceeding is under the arbitrator's jurisdiction and control and the arbitrator's decision is to be based upon the evidence and testimony presented at the hearing or otherwise incorporated in the record of the proceeding. The arbitrator may, unless prohibited by law, proceed in the absence of any party who, after due notice, fails to be present or to obtain postponement. An award rendered in an ex parte proceeding of this nature must be based upon evidence presented to the arbitrator.
Ill. Admin. Code tit. 56, § 110.110