Investing In Expertise; The Growing Demand For Expert Witnesses In International Arbitration




International arbitration has emerged to be the preferred forum for resolving cross-border disputes with increased reliance on expert witnesses. Detailed and cogent evidence forms the basis of a good case, thereby persuading parties to invest in experienced experts. Reliable evidentiary knowledge encourages arbitrators to appoint expert witnesses to assist and reassure them in their decisions. However, it is incorrect to presume that expert witnesses are used rampantly as it remains at a nascent stage in India when compared to Singapore, USA, or UK, requiring further recognition and acceptability. The article examines the approach taken towards expert witnesses in international arbitration and the rules governing them.

I. Who Is An Expert?

The role of an expert witness (or simply an ‘expert’) is to opine on specialist matters beyond the expertise of the tribunal. Expert witnesses play a crucial role in providing specialized knowledge and insights to assist arbitral tribunals. They serve an advisory role, assisting the arbitrator in interpreting evidence presented. Their primary duty is to the arbitrator, ensuring their testimony is objective and accurate.

Expert witnesses can be segregated into two categories namely being party appointed expert witnesses and tribunal appointed expert witnesses. Further sub-categories of an expert witness are of technical, quantum, and legal. A technical expert provides opinions and testimony on industry specific aspects related to the subject matter of the lis thereby providing invaluable expertise in complex technical nuances. A quantum expert assesses the monetary loss incurred by a party including the evaluation of accounts, economic data, and damages to quantify the loss. Their expertise is crucial in disputes where determination of damages is a key issue. Legal expert witnesses offer opinions and testimony on issues from different jurisdictions that may be unfamiliar to the arbitral tribunal, particularly in cases involving multiple laws governing the dispute due to the different nationalities of the parties.

II. Rules Governing An Expert Witness

Institutional arbitration rules and soft law instruments are key in regulating expert witnesses in international arbitration.

Institutional Arbitration Rules

A. SIAC Rules, 2016

i. Rule 26 provides the power to the Tribunal to appoint an expert. Such an expert appointed by the Tribunal is then cross- examined by both parties.

ii. Rule 25(1) clarifies that witnesses includes expert witnesses but otherwise offers no further guidance on mode and methodology.

B. UNCITRAL Rules, 2010

i. Article 27.2 provides that witnesses, including expert witnesses, who are presented by the parties to testify to the arbitral tribunal on any issue of fact or expertise may be any individual, notwithstanding that the individual is a party to the arbitration or in any way related to a party.

ii. Article 29 contemplates the process of appointing a tribunal appointed expert.

iii. Article 27.4 provides that the arbitral tribunal shall determine the admissibility, relevance, materiality, and weight of the evidence offered.

Soft Law Instruments

A. IBA Rules on the Taking of Evidence in International Arbitration [2020]:

i. Article 5 extensively sets out a mode and method for taking evidence from a party appointed expert:

a. Article 5(2) sets out the contents of an expert report. 5(2)(c) requires the expert to affirm his impartiality.

b. Article 5(4) affirms the concept of ‘hot tubbing’ and allows for expert witnesses to interact and narrow the controversy.

ii. Article 6 extensively sets out a mode and method for taking evidence from a tribunal appointed expert:

a. A consultative process is contemplated for the appointment of a tribunal appointed expert. Both in terms of the individual and also the terms of reference.

b. Given the exalted position afforded to the Tribunal Appointed Expert, the parties are permitted to object to the appointment of an expert in terms of Article 6(3).

c. Article 6(6) provides that the Tribunal appointed expert shall be subject to cross examination by both the tribunal and also the parties (through lawyers/other experts).

B. Chartered Institute of Arbitrators Protocols for the Use of Party-Appointed Expert Witnesses in International Arbitration:

i. Article 4 read with Article 8 sets out extensively the standards of impartiality expected of an expert witness and also their duties.

ii. Article 6 provides a working mechanism for the leading of an expert witness and their cross examination.

Independence & Impartiality Of The Expert

It is now almost universally accepted that a party-appointed expert must be independent and objective. For example, Article 5(2) of the International Bar Association (IBA) Rules on the Taking of Evidence in International Arbitration (the IBA Rules) requires that a party-appointed expert must disclose ‘his or her present and past relationship (if any) with any of the Parties, their legal advisors and the Arbitral Tribunal’ and provide ‘a statement of his or her independence from the Parties, their legal advisors and the Arbitral Tribunal’. Certain guidelines and practices go further, particularly those influenced by English court procedures. This is best illustrated by Article 4 of the Chartered Institute of Arbitrators’ Protocol for the Use of Party-Appointed Expert Witnesses in International Arbitration, which stipulates that ‘[a]n expert’s opinion shall be impartial, objective, unbiased and uninfluenced by the pressures of the dispute resolution process or by any Party’ and that ‘[a]n expert’s duty, in giving evidence in the Arbitration, is to assist the Arbitral Tribunal to decide the issues in respect of which expert evidence is adduced.’ Whether or not party-appointed experts are considered to have an overriding duty to the arbitral tribunal, it is clear that experts must not be partisan advocates or ‘hired guns’, tailoring their evidence to suit the party that has appointed them.


Expert witnesses are indispensable in international arbitrations. Arbitral tribunals are to carefully gauge the objectivity and reliability of expert witnesses and counsels need to admonish experts that perform poorly, display excessive partisanship, and undue defensiveness, inconsistencies, and an unwillingness to make strategic concessions. By adhering to governed practices and ethical standards, expert witnesses can significantly contribute to the effectiveness and creditability of the arbitration process.

Author: Anjali Sharma


Interns and Paralegals.


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