Cross Examination of Expert Witness before Arbitral Tribunal: An Outlook

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An expert is a person of peculiar knowledge or skill as to some particular subject, such as any art or science, or particular trade, or profession, or any special branch of learning; or is professionally or peculiarly acquainted with its practices and usages; a person who has technical or peculiar knowledge in relation to the matters with which the mass of mankind are supposed not to be acquainted; he who has some special, particular or practical knowledge in relation to some special department of the affairs of men as would qualify him to stand as an expert, skilled enough to teach others.[1] In the case of, Board of Education of Claymont Special School Dist. v. 13 Acres of Land in Brandywine, Del Super[2], it was held that, expert testimony, is in fact, opinion evidence of some person who possesses special skill or knowledge in some science, profession or business, which is not common to the average man and which is possessed by the expert by reason of his special study or experience. Expert evidence is almost invariably given in the form of a written report which is produced prior to the hearing and on which the expert is cross examined at the hearing.[3] It is settled law that it is permissible to an arbitrator to take assistance of experts (including institutional experts such as Institute of Engineers) in technical matters, in so far as such assistance is necessary, for discharge of his duties.[4]

The Construct: It is often advised that while preparing for cross examination of an expert it is practical to think of the ‘expert opinion’ as a conceptual construct built on several distinct pillars such as: in-depth understanding of the expert of the subject, profound experience of the expert in the field of his expertise, impartial (independent) opinion of the expert which is free from client bias and the ability of the expert to cite authorities to offer credence to the conclusion reached by the him. One of the principal objectives of cross examination is to erode as many of these pillars as possible so that the entire construct collapses, and the opinion rendered by the expert ‘not favouring’ the party cross examining it can be neutralized. It can be stated without elucidation that if the court/arbitral tribunal loses confidence in the opinion of the expert even on a few issues then it will cause the court/arbitral tribunal to question the opinion of the expert on all other issues, and this is particularly true when the opinion of the expert reads more like a statement of an advocate than that of a neutral and impartial expert. The risks of asking open questions about an expert witness’s independence are well worth taking, since the potential downside is minimal and the potential upside are significant.

Impartiality of an expert witness is the nerve of the entire expert testimony which if attacked in a tactful and efficient manner then the entire testimony of the expert witness often runs into the risk of collapsing. Thus, most often a cross examiner begins questioning the expert witness by asking him about any past or present relationship that the expert enjoyed/enjoys with the party who appointed him. The expert witness can also be asked as to when and how many times in the past was he appointed as an expert examiner by a party concerned and to depose on what all issues. When adducing expert evidence, it is expected of the party bringing to fore the expert testimony before the court/arbitral tribunal to satisfy the court/arbitral tribunal as regards what are the intrinsic/disputed issues which require expert testimony and how will the specific, party appointed expert will be of help and assistance to the Hon’ble court/arbitral tribunal to reach a conclusion justified in law. It is settled law that if an expert testimony appears to be demonstrably partisan and the issues that the expert is called to address are not central to the controversy at hand then it is highly unlikely that the court/arbitral tribunal will offer him (expert) platform to espouse his partisan views, instead, court/arbitral tribunal will remain unmoved by the expert testimony and will eventually label it as unjust. Moreover, if an expert witness fails to testify at the hearing before the court/arbitral tribunal then the evidence of such an expert witness is allowed to fade away into oblivion.

It is advisable for a cross examiner to investigate as to what all academic and professional credentials are typically obtained by experts in their respective field of expertise, and then to test whether or not the adverse expert witness possesses such credentials. If the adverse expert witness does not have the requisite credentials then his testimony can fail on account of lack of necessary knowledge and skill set. Even if an adverse expert witness has stellar academic credentials, then also it is be possible to attack the reliability of his evidence by demonstrating a complete lack of practical experience and insight. Another approach to attack an expert testimony is by demonstrating that the opinion rendered by him is beyond his precise field of expertise and thus, on this short ground the entire testimony rendered by him should pale into insignificance.

One of the pillars of the opinion rendered by an expert witness is consistency and to demolish this pillar it is crucial to determine whether or not the concerned expert witness has previously expressed his views on the expert issues in dispute. If the previously expressed views of the concerned expert witness (which may also be available in public domain) are at variance with his views expressed in the matter at hand then this can serve as powerful ammunition for challenging both the substance and propriety of his expert testimony in the cross examination. In case the adverse expert witness has been previously criticised in any other matter by the court/arbitral tribunal on the grounds of lack of objectivity or lack of understanding of the subject then the observations of the court/arbitral tribunal discarding the testimony of the said adverse expert witness can be tactfully used against him to cast an impression on the present court/arbitral tribunal hearing the matter that the said adverse expert witness is not worth his salt. One line of attack that can certainly be adopted against an adverse expert witness is to demonstrate before the concerned court/arbitral tribunal that the said expert witness has pre-conceived point of view impressed in his skill set that prevents him from considering the disputed expert issues in an unprejudiced (objective) and open-minded manner.

One of the most conventional methods of attacking the expert testimony is by pressing before the court/arbitral tribunal that the concerned expert witness while formulating his opinion failed to take into consideration the entirety of factual aspects qua the particular case at hand and/or the methodology adopted by the concerned expert witness to draw the requisite conclusion was ill-conceived. The most powerful way to challenge an expert witness’s factual assumptions is by demonstrating that the factual assumptions of the expert witness are contrary (opposing) to the evidence on record. If it can be shown that the expert witness neglected to read or consider any of the important documents on record that do not support the proposition he formulated or he cherry-picked the evidence relied upon by the parties to the case in reaching his considered opinion, then this will not only undermine the substance of the opinion rendered by the expert but it will also erode his credibility in toto. It is essential to note that when the opinion of an expert is attacked based on the choice of methodology that he adopted to draw the requisite results, then it is most relevant to demonstrate before the court/arbitral tribunal that the methodology that the expert adopted was not fit a methodology to be adopted in the case at hand owing to the special facts that require special consideration in the case.

In case an expert is nominated (appointed) by the court/arbitral tribunal then the most successful way to approach the fine task of cross examining the tribunal’s expert is first to elicit confirmation on all points on which the expert is in agreement with the lawyer’s case, for there will always be some points of agreement. Then the challenge is to draw the attention of the expert (and that of the tribunal) on the shortcomings of the reasoning adopted by the expert on the points on which the expert does not agree with the case set up by the lawyer and other authoritative texts and analyses which support the case made out by the lawyer.

When scientific tests, financial modelling or any other type of complex or time consuming analyses have been undertaken by an expert along with a team of other individuals supporting him in drawing the requisite analysis, then it is worth exploring in cross examination as to who exactly carried out what particular work and how closely were the members of the supporting team were supervised. It can be a case where by the expert witness delegated a particular work to any other individual who may be lacking the vital skill set required for carrying out the requisite work that is to be undertaken and that individual being not qualified enough to carry out the work with meticulous precision.

If it can be demonstrated that the expert witness is not particularly familiar with the nature and the scope of the work performed by the parties to the arbitration, then it can be asserted without seeming dispute that the arbitral tribunal would not be correct in relying upon the conclusions reached by the expert witness, for the expert witness has failed to appreciate not only the nature and the scope of the work, but also he could not be relied upon for having appreciated the minute yet intrinsic details qua the work at hand, and therefore, with apparent ease the analogy drawn by the expert can be pressed to be rejected for being defunct.

Hot Tubbing: The technique of ‘hot tubbing’ is often referred to as ‘witness conferencing’, and sometimes it is referred to as ‘concurrent expert evidence direction’. It is a technique in which two or more expert witnesses (one expert witness led by each of the parties to the dispute) are questioned together on particular topics by the arbitral tribunal and possibly by the counsels involved in the case. The core idea is, rather than simply hearing expert testimony from each side sequentially, the arbitrator questions the experts brought forth by each party to the case concurrently. The technique of ‘hot tubbing’ has been used in court settings and in arbitrations in Australia, England and Wales; however, this technique of ‘concurrent expert evidence direction’ is not admired in India (neither in court settings, nor in arbitrations). The technique of witness conferencing is particularly useful when there is significant disagreement between the experts and when the arbitrator needs to be educated about the intricacies of the underlying case. It was noted in the case of, Harrison & Ors v. Shepherd Homes Ltd & Ors[5], by Ramsey, J. that hot-tubbing is a successful technique to deal with expert evidence.

Section 26 of the Arbitration and Conciliation Act, 1996: There was no provision as regards ‘expert evidence’ in the Arbitration Act, 1940 (Act No. 10 of 1940). Section 26 of the 1996 Act corresponds to Article 26 of the UNCITRAL Model Law and it deals with the power of an arbitral tribunal to appoint one or more experts and refer to them specific issues for opinion, however, the parties to the arbitration can exclude the power and discretion conferred to the tribunal by virtue of Section 26 of the 1996 Act. Section 26 of the 1996 Act provides for the duties and the rights of the parties when expert is appointed. As per the mandate of Section 26 of the 1996 Act, if any party desires to lead evidence of an expert witness then permission should be given on specific issues. It is usually advisable to allow only one expert on a specified issue by each party. If the expert nominated by the party to the case and the expert appointed by the arbitral tribunal differ, then the tribunal may direct the experts (party appointed expert and tribunal appointed expert) to meet amongst themselves and attempt to sort out the differences. Usual practice is that, the expert appointed by a party supports the case of the party which appointed it, thus, the other party if seeks to cross examine the expert the permission for the same is to be given as a matter of norm by the arbitral tribunal. If an expert witness fails to appear without just cause then his evidence is to be disregarded by the arbitral tribunal. Where there are too many experts, that is, each party leads its own expert evidence by appointing its own expert, and if the views of the experts on the subject matter under consideration differ then, it makes it utmost difficult for the arbitral tribunal to reach just conclusion on the issues especially of technical nature, therefore, in such fact situations the arbitral tribunal can examine by itself the party-appointed-expert and can for better clarity over the issues in controversy consult an independent expert who is well acquainted with the specifics of the issues at hand so that the matter in controversy can be put to rest successfully. It is essential to note that ‘opportunity to put questions to the expert’ and ‘cross examination’ of the expert are two different things which operate in different fields.

Cross examination of the expert, as is normally done in case of witnesses, is not envisaged by the provisions of the 1996 Act.[6] Cross examination of a witness, in the ordinary course, is when the witness gives an affidavit or makes an oral statement on oath in the form of examination-in-chief. In case an expert gives a report on a specific issue, then such a report cannot be considered to be examination-in-chief. Further, as per the mandate of Section 26 of the 1996 Act, opportunity of putting questions to the expert is given to both the parties to the case. Moreover, even otherwise, there seems to be no situation contemplated in the Indian Evidence Act, 1872, where by both the parties can cross examine a particular witness. Invariably, the party producing the witness gets the statement of the witness recorded in the form of examination-in-chief and the examination of the witness by the adverse party is called the cross examination. As per the provisions of the 1996 Act, an expert can only be asked questions directly related to the report which he furnishes, but in case of cross examination, as per Section 138 of the Indian Evidence Act, 1872, cross examination need not be confined to the facts to which the witness testified on his examination-in-chief. If an expert was intended to be allowed to be cross examined by the legislature, then instead of stipulating that the expert can be ‘put questions’ in Section 26 (2) of the 1996 Act, it would have been stipulated that the expert can be subjected to ‘cross examination’.

The Strategy: Once the cross examination of an expert is underway it is least suggestive that one should change the planned sequence of his questions. Expert witnesses have a tendency to deflect questions posed to them by raising side topics or new matters. A cross examiner should not get distorted by them. Every cross examiner has structured the cross examination that is to be taken in a certain way in form of chapters for good reasons and it is always advisable for a cross examiner to remain firm in his plan of attack. But, to be firm in the plan of attack does not mean to be rigid, it only means that the cross examiner must always know how to progress or flex the cross examination as it evolves. If a particular line of questioning gets bogged down, then nothing can be gained by arguing endlessly with the expert witness. It is always advisable for the cross examiner to move to different short and strong chapters that he has prepared to elicit quintessential admissions from the expert witness,  that will allow him to reassert control and refocus the attention of the arbitral tribunal on the case theory which the cross examiner is trying to project.


  1. Expert testimony is evidence of persons who are skilled in some art, science, profession, or business, which skill or knowledge is not common to the general mass of mankind, and which has come to such experts by reason of some special study and experience in such art, science, profession or business.
  2. It must always be remembered that cross examination is not a “dark art” but is rather a product of know-how, hard work and practice.
  3. It must always be remembered that arbitrators will allow expert testimony only as regards the issues qua which they themselves are less knowledgeable.
  4. Cross examination of expert witness is not envisaged by the provisions of the 1996 Act (See: Section 26 (2) of the 1996 Act).

[1] P. Ramanatha Aiyar’s Advanced Law Lexicon, Third Edition, p. 1722

[2] 11 Terry 387, 131 A 2d 180

[3] Russell on Arbitration, Twenty First Edition, Para 5.172, p.229

[4] Juggoboundhu Saha v. Chand Mohan Saha, AIR 1916 Cal 806 (DB)

[5] (2011) EWHC 1811 (TCC)

[6] P.C. Markanda, Arbitration: Step by Step, Second Edition, Lexis Nexis, p.385

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