Evidence - ICSID Convention Arbitration (2022 Rules)

Each party has the burden of proving the facts relied on to support its claim or defense (Arbitration Rule 36(2)). The Tribunal has discretion to determine the admissibility, weight and credibility of the evidence adduced (Arbitration Rule 36(1)).

Parties file their evidence with their written pleadings. Evidence filed in the written process may include exhibits, witness statements, expert reports, audio and video files. Such evidence must be filed together with the submission to which it relates (Arbitration Rule 5).

A party may also ask a Tribunal to conduct a site visit at a place connected with the dispute (Arbitration Rule 40).

The type of evidence to be filed and the manner, form and timing of filing are usually discussed at the Tribunal's first session and set out in Procedural Order No. 1. If the evidence is in a language other than the procedural language of the case, it must be submitted in the original language together with a translation. Lengthy documents that are relevant only in part need to be translated only insofar as relevant, unless the Tribunal requires a translation of the complete document (Arbitration Rule 7(4)).

The parties and the Tribunal often agree that the Tribunal may be guided by the International Bar Association Rules on the Taking of Evidence in International Arbitration (the "IBA Rules of Evidence") when considering the admissibility of evidence and other evidentiary issues. They also often agree that, absent exceptional circumstances, neither party may file additional evidence after the submission of the last written pleading.

Types of Evidence and Other Supporting Documents

Exhibits are documents that the parties rely upon to prove or disprove facts relevant to the dispute. Exhibits should be numbered individually and consecutively throughout the proceeding. The numbers are typically preceded by the letter "C-" for the claimant's exhibits and "R-" for the respondent's exhibits.

Arbitrations often include a document production stage, in which both parties can request certain categories of documents from one another (see Document Production). In addition, at any stage of the proceeding  the Tribunal may call upon a party to produce documents or other evidence  it deems necessary (Arbitration Rule 36(3)).

Legal Authorities are sources of law that the parties rely upon to prove relevant points of law related to the dispute. These are also numbered individually and consecutively throughout the proceeding, and the numbers are typically preceded by the letters "CL-" or "CLA-" for the claimant's authorities and "RL-" or "RLA-" for the respondent's authorities.

A Witness Statement is a written statement by a witness addressing the pertinent facts in the dispute of which they have knowledge. The statement must identify the witness, contain the evidence of the witness, and be signed and dated (Arbitration Rule 38(1)).

An Expert Report is an opinion by an expert witness addressing specific aspects of a case that are within their area of expertise. Expert reports are often filed on the application of a particular law, on technical matters or on the calculation of damages. The expert report should review the expert’s qualifications, list the instructions on the basis of which the expert proceeded, and discuss how the expert reached his/her conclusions.

Generally, each party produces its own witnesses and appoints its own experts. The Tribunal may call upon the parties to produce further witnesses and experts if it deems it necessary (Article 43 of the ICSID Convention, Arbitration Rule 38). The Tribunal may also appoint its own expert, unless the parties agree otherwise (Arbitration Rule 39). 

Each witness statement and expert report must be signed and dated and will stand as evidence in chief unless disputed by the other party (Arbitration Rule 38(1)).  A witness who has filed a written statement may be called for examination at a hearing (Arbitration Rule 38(2)). The examination is held in person unless the Tribunal determines that other means of examination are appropriate in the circumstances. For example, the Tribunal and the parties might agree that a witness can testify by remote means (Arbitration Rule 38(5)).

Demonstrative Exhibits (e.g., PowerPoint Presentations, charts and graphs) may be used at a hearing provided they contain no new evidence and identify the evidence on record from which they are derived.