In Peruvian domestic arbitration, the participation of experts constitutes a technical means of evidence primarily governed by Legislative Decree No. 1071, aimed at assisting the arbitral tribunal in the understanding and assessment of facts that require specialized knowledge beyond the legal sphere. The expert acts as an assistant to both the tribunal and the parties, providing a technical opinion that contributes to the determination of the disputed facts, under the principles of adversarial proceedings, impartiality, independence, and due process. Their appointment may be made either by the parties or by the arbitral tribunal itself, in accordance with the applicable rules.

From a functional perspective, the expert report plays an instrumental role in the formation of the arbitral tribunal’s conviction, particularly in disputes of a technical, economic, or specialized nature. The expert opinion is not binding and is subject to the tribunal’s free assessment, which must evaluate its technical consistency, the methodology applied, and its internal coherence in conjunction with the other evidentiary elements. In this way, the expert’s involvement strengthens the reasoning of the arbitral award and contributes to its quality and legal soundness, in line with the standards of domestic arbitration and the system of limited judicial review of arbitral awards.