Experts in Arbitration: Why A Hired Gun Will Often Come Undone!

Nov 2020


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Although it is tempting to instruct a “hired gun” who is willing to adjust his opinion to suit the client’s case, this could be detrimental to the final outcome of the dispute. An expert’s independence is key and will play into his expertise, preparation and court performance.

You can read more about experts in arbitration and common pitfalls encountered below.

Role of Experts

Experts often play an integral role in ensuring the fair and just resolution of arbitration disputes. In technical and complex disputes, expert witnesses are necessary to assist the Tribunal in answering specific questions and to understand the issues in dispute that need to be resolved.

Duty to the Tribunal

The primary and overriding duty of an expert is to assist the Tribunal on matters within his expertise. This duty overrides any obligation to the client, even though the expert is appointed by a party. Despite proximity with the client, independence and impartiality must be retained and the expert must not favor the party whom he has received instructions from or is paying his fee.

There are various rules applicable to international arbitrations designed to help ensure an expert’s impartiality such as the International Bar Association Rules on the Taking of Evidence in International Arbitration 2010 (“IBA Rules”). They are designed to be used in conjunction with institutional, ad hoc or other rules or procedures governing international arbitrations. Particular IBA Rules designed to assure an expert’s impartiality include:-

    • Article 5(2)(a) – Disclosure of any present and past relationship with the parties, legal advisors and the Tribunal;
    • Article 5(2)(c) – A statement of independence; and
    • Article 5(2)(g) – An affirmation of genuine belief.

Duty to the Client

That said, although the expert’s overriding duty is to the Tribunal, this does not mean he owes no duty towards his client.

Historically, experts enjoyed general immunity from negligence claims in circumstances where they are acting as an expert witness. However, the landmark decision of the Supreme Court of the United Kingdom in Jones v Kaney[1], abolished an expert witnesses’ immunity from suit for breach of duty (in contract or in tort) for their participation in legal proceedings. As a result of that decision, experts owe a duty of care to their client in respect of the advice they give.

Despite the significant change in position, there remains no conflict between the expert’s overriding duty owed to the Tribunal and his duty of care to his client.

Common Pitfalls – Where Experts tend to go wrong…

The Hired Gun

Unlike factual witnesses, expert witnesses are paid to testify on behalf of the client. Consequently, experts are often expected to be the client’s mouthpiece.

The opinions of hired guns are often carefully written with an aim of leading the Tribunal to a desired outcome. They achieve this by discrediting alternative applicable arguments or through lesser reliance on harmful information. Impartial experts who use methodologies skewed to assist their client’s case will end up having opinions which are completely inconsistent with other experts. It is often difficult for a Tribunal, without the prerequisite expertise, to detect the hired gun’s biased opinion.

Instructing an expert as a hired gun should therefore be avoided because they end up polarising the parties, are of no assistance to the Tribunal, and usually derail any progress made towards the resolution of the dispute.

How to tell the difference between a Hired Gun and a Straight Shooter

Common (concerning) qualities of a hired gun include:-

    • He says he is willing to give a particular opinion for the right price.
    • He offers an opinion consistent with your case before reviewing any documents.
    • He claims to have “special methods” which only he understands.
    • He has a track record of always agreeing with his client’s case in its entirety.
    • He has been criticised by judges / arbitrators in past decisions for being impartial.

The test of admissibility of the expert’s evidence is whether:-

    • He has the relevant expertise; and
    • He is aware of his primary duty to the tribunal if he gives expert evidence and is willing and able to, despite the interest or connection with the dispute or party, carry out that duty[2].

The Slippery Slope to Losing Independence and Becoming a Hired Gun

An expert should not only be independent but must also be seen to be independent. The expert’s independent assistance to the Tribunal should also be an objective and unbiased opinion on matters within his expertise. The following are examples of situations which can give rise to bias and should therefore be avoided:-

    • Bias arising from a contingency fee agreement. This is strongly discouraged. If necessary, an alternative would be to use a deferred fee payment arrangement which does not hinge on the outcome of the case.
    • Bias arising from a conflict of interest e.g. financial interest, a personal connection or an obligation from being a member of a body. If this is applicable, the expert should identify this as soon as possible so that the Court / Tribunal can decide whether there is a material or significant conflict of interest such that it will decline to act on the expert evidence or decline permission for it to be adduced.
    • Bias arising from the expert’s involvement in the subject matter of the dispute e.g. where the expert was involved in the underlying dispute on which he would have to provide a view. In this situation, it would be best if the expert was involved as a factual witness instead.
    • Bias arising from the expert’s status or position e.g. a barrister acting as an advocate representing a party will be disqualified from giving expert evidence even though he is competent.
    • Bias arising from coaching. The evidence of experts who have been coached may be excluded.

Into the Hot Tub he goes… the Hired Gun Exposed  

Even if a professional hired gun can hide his impartiality and cope well under the traditional process of Counsel’s cross-examination, he might not be able to escape his hot-tub experience unexposed.

Hot-tubbing (aka duelling experts) is a process where experts give evidence and are cross-examined concurrently in each other’s presence before the Tribunal puts the same questions to each of them in turn and allows them to debate the accuracy of their opinions. The Tribunal, in effect, chairs the duel between the experts. This hot tub process can be adopted after or instead of traditional cross-examination.

When in discussion with another expert, the hired gun may concede on technical issues which he may have resisted under Counsel’s cross-examination. The hired gun’s more extreme views will likely be moderated when he is required to justify his opinion. Also, when being cross-examined by a peer, it is usually obvious if the hired gun is talking outside of his expertise for the benefit of the client.

The benefit of hot-tubbing is that disagreements on technical issues and extreme or biased views can be reduced. Also, most expert issues can be considered and possibly decided all at once rather than at different times of the trial. This can be conducive to a more amicable and earlier settlement.

When the Hired Gun Misfires… the Client is the Casualty

Generally, if an expert has a conflict of interest, whether he will be disqualified from giving evidence will depend on the specific facts of the case. An expert’s opinion will usually be inadmissible if he has a direct financial interest in the outcome of the case. Where the expert has a personal or other connection with a party that may consciously or subconsciously influence or bias his opinion, he will not be automatically disqualified but it will have an impact on the weight to be attached to his opinion.

When the hired gun does not perform as planned and is found out, the client bears the ultimate consequence of having inadmissible or tainted expert evidence. As experts can be fundamental to the resolution of the case, instructing a hired gun must be avoided.

In summary, if an expert is not independent, it harms his credibility and ultimately the client. Although it is always tempting to use a hired gun, just remember he will more often than not come undone!

[1] [2011] UKSC 13

[2] Armchair Passenger Transport Ltd v Helical Barr Ltd [2003] EWHC 367, [29] (QB)


Paul Starr is the head of KWM’s Hong Kong Dispute Resolution team and the Global Joint Coordinator of our International Arbitration team. His encyclopaedic knowledge of construction law cases is rivalled only by his sommelier-like knowledge of Bordeaux reds. In the pre-COVID era, Paul spent his time living between Hong Kong and Cathay Pacific’s global fleet, following clients and their disputes all over the world, from Germany to Guatemala. When he’s not working, wining, dining or travelling, Paul has a penchant for putting together legal mini-plays (they are pretty good – and he is expecting a call from Netflix any day now).

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