9.1  Article 6 of the IBA Rules addresses the use of tribunal-appointed experts. Read together with Article 8, which deals with procedural aspects of oral testimony at the evidentiary hearing, it provides a comprehensive framework for the use and management of evidence from such experts.

9.2  The matters covered in Article 6 include the appointment and terms of reference of a tribunal-appointed expert, a party’s right to object to the appointment, the content of the expert’s report, the parties’ right of response to the expert evidence, and the right to examine the expert at the evidentiary hearing.

9.3  As already mentioned in relation to Article 5, although Article 6 is a relatively self-contained code on tribunal-appointed experts, it is important to understand the relationship and differences between the provisions of Article 6 and those contained in Article 5 dealing with party-appointed experts. Those drafting the IBA Rules faced the same challenges in reconciling the competing historical and cultural preferences of different legal traditions in relation to expert evidence as they did in connection with other aspects of procedure affecting the taking of evidence. However, rather than adopting a single or merged approach from one or other legal tradition, the drafting committee adopted a dual approach representing prevailing practice in both common law and civil law systems.¹ Article 5 makes provision for party-appointed (p. 326) experts (the traditional common law preference) while Article 6 addresses tribunal-appointed experts (most commonly used in civil law systems² and in the UNCITRAL Model law).³ These two articles reflect the available mechanisms under the IBA Rules (and in the practice of international arbitration generally) by which expert evidence is introduced.

9.4  The terms of Articles 5 and 6 reflect the different concerns and issues that arise in relation to the use of each of party-appointed and tribunal-appointed experts. As mentioned, a key objective of Article 5 is to make sure that there is transparency and a degree of assurance around a party-appointed expert’s independence. Article 6 contains checks and balances designed to ensure that the tribunal does not delegate its decision-making function to a tribunal-appointed expert, that the parties have a proper opportunity to make representations on the choice of expert, and to examine and comment on the evidence presented by that expert.

9.5  Issues that routinely arise in relation to the appointment of a tribunal-appointed expert include the following:

1. (i)  whether or not the case is suited to the use of a tribunal-appointed expert;

2. (ii)  selection of the expert and the expert’s terms of reference;

3. (iii)  what material is to be provided to the expert;

4. (iv)  whether the expert is to be able to seek further material or information from the parties and, if so, what the procedure is for such requests;

5. (v)  the procedure for enabling the parties to comment on the expert’s report;

6. (vi)  the procedure to be adopted at the hearing in relation to presentation of the expert’s evidence; and

7. (vii)  whether and in what circumstances the parties are to be entitled to rely on party-appointed expert evidence.

9.6  A number of published materials contain useful guidelines on issues that the parties and/or a tribunal may wish to consider in connection with the use of tribunal-appointed experts.⁴

9.7  An IBA report indicates that Article 6 is relied upon in about 8 per cent of cases in which reference is made to the IBA Rules.⁵

9.8  Article 6.1 deals with the process for appointment of a tribunal-appointed expert. Importantly, it provides for consultation with the parties. This is desirable both to engage the confidence of the parties in the appointment, and to ensure that the issues to be put to the expert meet the needs of the case.

9.9  Article 6.1 expresses the right of a tribunal to appoint an expert to report on specific issues selected by the tribunal. It may do so ‘after consulting with the parties’. Subject to observing the requirement of consultation, Article 6.1 appears to give a tribunal the right to appoint an expert even where party consent is not obtained. While the Commentary to the IBA Rules makes clear that an important principle underlying Article 6 is the substantial involvement of the parties at all stages of the process, it does not suggest that the tribunal may not make an appointment unless it has the consent of the parties.

9.10  A number of institutional arbitration rules contain similar provision giving the tribunal broad authority to retain experts directly, after consultation with the parties.⁶

9.11  Many national arbitration laws also make provision for the appointment of tribunal-appointed experts where the parties have not agreed otherwise - for example, Article 26 of the UNCITRAL Model Law⁷ and Section 37 of the English Arbitration Act.⁸ Section 25 of the Swedish Arbitration Act provides that the tribunal may appoint an expert unless both parties are opposed to such a course. Although the formulation adopted by the Swedish legislation differs from that in the UNCITRAL Model Law and the English legislation, from a practical perspective the outcome is the same. In other countries—for example, Switzerland, France, Belgium, and (p. 328) the United States—the parties’ right, and the tribunal’s power, to determine the arbitral procedure has generally been interpreted as permitting the appointment of tribunal-appointed experts.⁹ However, regardless of any formal requirements imposed in relation to the appointment of such an expert, there are very good reasons why a tribunal should consult and/or seek approval from the parties before making the appointment—not least because of the need to fund payment of the expert’s fees, which is impossible without the cooperation of at least one party. In all cases, building a consensus around the use of a tribunal-appointed expert, as well as the choice of expert, will aid the smooth running of the arbitration and minimize the risk that one of the parties will feel dissatisfied and/or later claim that the appointment adversely affected presentation of its case.

9.12  Where both parties are actively opposed to the use of a tribunal-appointed expert, a question arises in relation to party autonomy, ie is the tribunal entitled to proceed with the proposed appointment in the face of party agreement that it should not. Party autonomy is of fundamental importance to the arbitration process. However, a tribunal has obligations in connection with the arbitration that it may regard as inconsistent with an agreed position presented by the parties. For example, if the tribunal believes that the appointment of a tribunal-appointed expert will be the most efficient and useful way in which to obtain expert evidence, it may take the view that abandonment of that proposed approach breaches its general duty to conduct the proceedings in a fair, efficient, and economic manner.¹⁰ Such a position can create a dilemma for the tribunal, to which there is no easy answer. However, in practice, it is unlikely that the tribunal will proceed to make the appointment.¹¹

9.13  Although relatively rare, in some cases, the parties’ arbitration agreement may exclude the right of a tribunal to appoint an expert. This may mitigate the tribunal dilemma of balancing party autonomy and tribunal duties, but it is not without risk. Situations do sometimes arise in which the tribunal feels that expert evidence presented by party-appointed experts is inadequate in some way, or that it would benefit from the assistance of a third ‘independent’ expert in relation to certain aspects of the case. For example, in a situation where, despite opportunities given to the parties to supplement that evidence, the tribunal feels that the available party-appointed expert evidence is not convincing or is inconclusive. If the tribunal cannot appoint its own expert, it may simply decide that the relevant party has not discharged its burden of proof. By depriving the tribunal of the opportunity to appoint an expert, the parties may jeopardize the outcome they seek.

(p. 329) 9.14  In summary, under the IBA Rules, unless the parties have agreed otherwise, a tribunal may appoint a tribunal-appointed expert after consulting with the parties. If both parties are against such an appointment, the tribunal would be ill-advised to proceed with it. However, where one party is for and another is against a tribunal appointment, the tribunal has the power to proceed with the appointment and should do so where considerations of efficiency, economy, and fairness support that decision.

9.15  Article 6.1 requires that the tribunal first consult with the parties before appointing an expert. The Commentary to the IBA Rules emphasizes how important it is that the parties are involved at each stage of the process. This is desirable in itself and may also reduce the risk of potential future challenges to the expert, the expert’s report, and/or to the award.

9.16  Consultation between the tribunal and the parties will generally involve consideration of a number of different topics relevant to the appointment.

9.17  The first question is whether it is necessary or appropriate to retain a tribunal-appointed expert. There are a variety of reasons why a tribunal may wish to do so.

9.18  For example, in a small number of cases, the tribunal may require assistance on technical issues that it finds difficult to understand without assistance, but which are not necessarily disputed. The tribunal may also wish to appoint an independent expert to review confidential or sensitive documents in relation to a disputed document production request and form the view that this is most appropriately done pursuant to the provisions of Article 6.¹²

9.19  More generally, the reasons for the appointment will be similar to decisions underpinning appointment of a party-appointed expert—most commonly, that there are disputed facts that the tribunal will find difficult to resolve without hearing expert evidence on the issue. In these circumstances, the key question will be whether it is better to use a single tribunal-appointed expert, or party-appointed experts (or possibly both). Pursuit of the overall objective of an ‘efficient, economical and fair process (p. 330) for the taking of evidence’ provided for in the Preamble to the IBA Rules may require careful consideration in relation to this matter.

9.20  The particular considerations relevant to this debate, and its timing, will be specific to an individual case. Where a tribunal requires general assistance to understand technical matters not in dispute, a single tribunal-appointed expert may be an obvious choice. Where expert evidence on disputed issues is required, then, depending on the preferences of counsel and the parties, positions may differ. Some tribunals may see a tribunal-appointed expert as being more efficient in terms of time and costs, as well as more independent. However, it should not be assumed that the appointment of a single tribunal-appointed expert will necessarily be faster or less expensive than the use of party-appointed experts. For example, the right of parties to be involved in the selection of an individual expert to be appointed by the tribunal, and the parties’ right to respond to the expert evidence presented by such an expert by means of evidence from a party-appointed expert can make this approach as time consuming and expensive as the appointment of experts by the parties.

9.21  In addition, it is possible that the parties may, in any event, exercise their right under Article 5 to present expert evidence on the same issue. The entitlement of a party to rely on party-appointed expert evidence is addressed in Chapter 8.¹³ Moreover, even without the formal appointment of a party-appointed expert, parties will sometimes appoint ‘shadow experts’ to assist them in formulating questions to the tribunal-appointed experts or a challenge to the expert’s conclusions. Counsel for the parties—particularly if they are from a common law jurisdiction—may oppose the appointment of a tribunal-appointed expert and argue that the requirement of a ‘fair’ process¹⁴ dictates that they should have the opportunity to present expert evidence from a party-appointed expert. Finally, it should be borne in mind that, in many cases, experienced party-appointed experts prepared to work cooperatively may be able to narrow the technical issues between the parties, thereby reducing the amount of evidence to be prepared and presented to the tribunal.

9.22  The English court has identified a number of factors to be considered when the court has to decide whether to order parties to an individual piece of litigation to appoint a single ‘joint’ expert, rather than individual party-appointed experts. Some of these factors are equally relevant to the decision to appoint a tribunal-appointed expert. They include:¹⁵

• •  the value of the dispute;

• •  the complexity of the issue;

• •  whether a party has already instructed an expert on the issue in question;

• (p. 331) •  whether the instruction of a single joint expert is likely to assist the parties and the court to resolve the issue more speedily and in a more cost-effective way than separately instructed experts; and

• •  whether the expert evidence falls within a substantially established area of knowledge that is unlikely to be in dispute or there is unlikely to be a range of expert opinion.

9.23  If the tribunal and the parties can discuss and agree on either a tribunal-appointed expert or party-appointed experts, then this is clearly desirable. Where parties insist on introducing party-appointed expert evidence, the tribunal may abandon the idea of a tribunal-appointed expert where it will simply duplicate costs and effort. However, as mentioned, if having considered party-appointed expert evidence a tribunal forms the view that such evidence is inadequate in some way, or that the tribunal would nonetheless benefit from the assistance of a third expert in relation to the technical matters in issue, then it may propose or revisit the idea of a tribunal-appointed expert. For example, both party-appointed experts may be credible, but they may be adopting materially different positions in their evidence such that the tribunal feels it necessary to appoint a third expert in order to assist the tribunal navigate through the competing views contained in the available evidence, even though this may result in additional delay and/or expense.¹⁶

9.24  Article 6 does not lay down any guidance as to the selection process of the tribunal-appointed expert. This is unsurprising. Much will depend on the facts of the case, the nature of the issues on which expert evidence is required, the knowledge and experience of counsel and the tribunal in relation to that discipline of expert, and the personalities involved. In practice, there are generally three options for a tribunal wishing to appoint an expert:

1. (i)  The tribunal may invite the parties to suggest a suitable expert, with a suggested default appointment mechanism in the event that the parties are unable to agree;

2. (ii)  The tribunal may approach a specialist institution for assistance in identifying a suitable expert¹⁷; and/or

3. (iii)  The tribunal may identify an expert using their own contacts.¹⁸

(p. 332) Depending on the facts of the case, there may be advantages and disadvantages to each of these three options. However, where the tribunal identifies an expert without prior consultation with the parties it would be prudent for it to seek prompt input from the parties on whether they believe the proposed expert to be suitable.

9.25  The search for an expert can be time-consuming and a tribunal may not always have access to the same level of resources as large law firms in carrying out that search. Its approach to the search may also be different. When counsel for one of the parties is looking for an expert, consciously or subconsciously they will be looking for an expert who will support their client’s case. To that end, lawyers often conduct a background check on the expert’s published works, in addition to his or her professional background and experience. A tribunal is likely to approach a search in a more objective way, ie it will merely wish to satisfy itself that the expert has the necessary qualifications and experience. The tribunal will also need to be alive to potential conflicts. In some areas of expertise there may be a very small pool of experts, some of whom may have an existing relationship with one of the parties or a member of the tribunal.

9.26  Article 6.1 provides that the tribunal may appoint an expert ‘to report to it on specific issues designated by the Arbitral Tribunal’. Those issues should be directly relevant to the dispute.

9.27  Depending on the stage reached in the proceedings, the tribunal may have a relatively clear view on the nature of the issues on which it requires assistance from an expert. However, it is important that the tribunal consult the parties. Not only is this an express requirement of the IBA Rules, but the parties may have a deeper understanding of the issues in dispute and the matters that they will need to demonstrate by reference to expert evidence in order to make their case. In order to avoid any suggestion that a party’s ability to present its case has been hindered in any way, it is essential that the parties be involved in formulating the issues to be addressed by the expert.

9.28  Efficiency and costs should also be borne in mind. The scope of the expert’s mandate will have a direct impact on the expert fees incurred. In general terms, limiting the scope of the evidence to that required to assist the tribunal to determine the dispute, or necessary to provide important background context for material issues, should be the underlying agenda.

9.29  Article 6.1 requires the tribunal to establish formal terms of reference for the Tribunal-Appointed Expert Report ‘after consulting with the Parties’.

9.30  The terms of reference to be provided by the tribunal to the tribunal-appointed expert is the equivalent of the instructions given by a party to a party-appointed expert. If done properly, instructions to a party expert will be couched in relatively objective terms. However, the instructing party will still have full control over what it wishes to (p. 333) say in the instructions and the directions it gives to the expert. The drawing up of terms of reference under Article 6 is a more tightly controlled process. During consultation on that document each party will wish to do what it can to ensure that (a) the matters it considers important are put to the expert and (b) the instructions given to the expert are not expressed in terms that favour one party over another. In our experience, it is common practice for draft terms of reference to be circulated to the parties for comment before being finalized. Another approach is for the tribunal to invite the parties to try to agree terms of reference. The terms of whatever they can agree is then produced and any points of disagreement are resolved by a decision of the tribunal.

9.31  The IBA Rules require the tribunal to send a copy of the final terms of reference to the parties.

9.32  Similar provision requiring consultation on terms of reference by which a tribunal expert is to be appointed can be found in Article 25 (4) of the ICC Rules:¹⁹

The arbitral tribunal, after having consulted the parties, may appoint one or more experts, define their terms of reference and receive their reports. At the request of a party, the parties shall be given the opportunity to question at a hearing any such expert.

9.33  The UNCITRAL Arbitration Rules approach the issue slightly differently. They require the Tribunal to communicate the terms of reference to the parties but contain no explicit requirement for the tribunal to consult with the parties on that document. In particular, Article 29(2) of the UNCITRAL Arbitration Rules provides:

A copy of the expert’s terms of reference, established by the arbitral tribunal, shall be communicated to the parties.²⁰

9.34  In our view, the express requirement to consult on the terms of reference found in in the IBA Rules is the better approach.

9.35  Article 6 does not contain any guidance as to what should be included in the terms of reference. The possible content of terms of reference is addressed in the next section, but, as a minimum, that document must set out clearly the scope and substance of the questions to be answered by the expert.²¹ The tribunal and the parties may also wish to include instructions on what is to happen should the expert identify an issue that has not been specifically addressed in the terms of reference.²² The tribunal and the parties will generally wish to indicate the documents and information to be considered by (p. 334) the expert, and any tests or investigations that should be conducted. A communication protocol between the expert, the tribunal, and the parties may also be considered for inclusion, along with appropriate procedural directions, and a timetable for production of the expert report.

9.36  The terms of reference provided to a tribunal-appointed expert will be tailored to the circumstances of the individual dispute and in practice are likely to be heavily influenced by the consultation with the parties on content that has taken pace. However, the following housekeeping points and general topics are frequently identified as matters to consider:²³

• •  Identification of the arbitration proceedings (parties to the proceedings and any institution number, etc.);

• •  Name and address of the expert. Where a professional partnership or other body is retained the individual assuming the role of expert should be identified;

• •  Any other aspects of the desired organization, preparation, and presentation of the evidence. For example, the format in which the expert report should be presented;

• •  A provisional timetable for preparation and delivery of the expert evidence;

• •  Definition of the expert’s tasks and the questions/issues that the expert must address in the expert report;

• •  An express statement of the power of the tribunal to adjust the expert’s terms of reference if so required by the expert’s findings (normally exercised after consulting the parties);

• •  Identification of information (documents, specimens, etc.) that are to be provided to the expert on which the expert should base his or her report;²⁴

• •  A procedure by which the expert may collect further information that the expert may require in order to prepare the report. For example, the rules under which the expert can contact the parties to request information or hold interviews with them;

• •  Rules for communications between the expert, the parties, and the tribunal designed to ensure transparency around the process by which the evidence is prepared;

• •  An express statement of the parties’ right to comment on the expert’s report and to question the expert at an oral hearing upon request, as well as confirmation of the expert’s agreement to attend the hearing;²⁵

• (p. 335) •  A statement of the expert’s related obligations. For example, the duty to maintain confidentiality, the obligation to be truthful and impartial, the duty to disclose the expert’s contacts with the parties, and potential conflicts of interests prior to and during the arbitration proceedings;

• •  Scope of the expert’s liability, and grounds for termination of the retainer;

• •  A statement of the expert’s rights in relation to the role for which the expert has been retained, and what the expert expects from the tribunal/parties;

• •  A statement of agreed arrangements in relation to remuneration and reimbursement of expenses (including fees for the expert’s employees and charges for travel and accommodation, if appropriate)—note that any advance payment should be recorded; and²⁶

• •  Basic rules for monitoring costs and readjusting the advance on expert’s fees.

A checklist of points to consider in relation to appointment of a tribunal-appointed may be found at Appendix 11.

9.37  It has been suggested that it is desirable for each member of the tribunal, the parties, and the expert to sign the terms of reference.²⁷ However, this is not a requirement of the IBA Rules and may not always be practical.

9.38  When a potential expert has been identified, the tribunal will normally approach the expert and ask whether they are able and willing to accept the appointment. The initial contact with a potential expert will focus on whether the expert has the required skills and expertise, is willing and available to assist without delaying the schedule for the arbitration, is independent and neutral, and does not have any conflicts of interest. It is advisable that all communications between the tribunal and a potential expert are conducted in writing and copied to all parties to avoid giving any grounds for future challenge to the expert, the report, and/or the award for lack of due process. It is good practice for the tribunal to send to the tribunal-appointed expert a copy of the IBA Rules.

9.39  Article 6.2 requires the nominated expert to provide the tribunal, and the parties, with details of the expert’s qualifications and a statement of independence so that the parties have an opportunity to raise any concerns they may have in relation to either of these matters. The provision goes on to set out a procedure by which any concerns are to be articulated and determined.

9.40  Article 6.2 does not require the expert to provide a statement of availability. However, during initial contact with a potential expert it is sensible for the tribunal to establish that the expert has sufficient time to devote to the proceedings and is available to attend any hearing dates that have been fixed.

9.41  Article 6.2 provides that the parties may object to the appointment of the tribunal-appointed expert on only two grounds: (a) the expert’s qualifications; and/or (b) the expert’s lack of independence.

9.42  In practice, there are other grounds on which the parties might reasonably take objection to an individual expert. These may include the inexperience of the proposed expert in giving expert evidence, the level of fees associated with the appointment, a reasoned preference for party-appointed experts, or that the proposed appointment will reduce the efficiency of the proceedings and/or increase time and costs to an extent that will outweigh any benefits to be derived from the appointment.²⁸ However, the arena for raising these issues is the consultation process prescribed by Article 6.1. After such consultation, and at a point where the tribunal has identified an expert that it wishes (p. 337) to appoint, the parties’ right of participation in the appointment process is limited to its right to raise a formal objection on one of the two discrete grounds mentioned. Although narrowly defined, these grounds provide important safeguards in relation to the expert evidence to be presented. The evidence of the expert will be of no value, and may even mislead the tribunal, if the expert is not suitably qualified to speak to the matters in issue. Likewise, if the expert is not independent, the evidence the expert gives may be partisan and therefore misleading or, if obviously one-sided, not something to which the tribunal can properly attach any weight.

9.43  Unlike a party-appointed expert, who is only obliged to describe his or her qualifications and independence in the expert report that is produced, a tribunal-appointed expert is required under Article 6.2 to submit this background information before being appointed. Clearly, in practice, the parties can only raise an objection to appointment on the grounds of lack of qualification if they have information on those qualifications. If the parties know the identity of the proposed expert, they can try to conduct independent research, but it is much more satisfactory for the expert to provide full details of his or her expertise so that each of the parties has access to the same information.

9.44  Against this background it is unclear why Article 6.4(a) requires the expert’s report to include a description of the expert’s background, qualifications, training, and experience while only a description of his or her qualifications is required at the stage of appointment pursuant to Article 6.1, in relation to which an objection may be raised. In practice, it is sensible for all of this information to be provided at the earliest stage.

9.45  As mentioned, the early timing of provision of information under Article 6.2 is in contrast to the position in respect of party-appointed experts where such details are only provided to all participants at the report stage. However, in that case, each party will have its own expert who it will have vetted carefully to check that the expert has the requisite knowledge and will make a good witness. The opportunity to challenge the credentials of the opposing expert will come during cross-examination or in closing submissions, where arguments are made as to the weight to be attributed to a particular piece of evidence.

9.46  As with the statement of qualifications, the provision of a statement of independence by the proposed expert prior to appointment is in contrast to the position in respect of party-appointed experts, where that statement need only be included in the expert’s report. The underlying rationale is also broadly the same. In the case of party-appointed experts, each party will have taken appropriate steps to investigate whether the expert has any connection with the opposing party. The appointing party is unlikely to select an expert with whom the appointing party has a significant existing relationship (p. 338) because this will ultimately have to be disclosed and, when it is, the tribunal may take this into account when weighing the evidence of that expert. Even if the appointing party is prepared to take this risk, the other party will have the opportunity to challenge the expert about the relationship during cross-examination. To some extent, these matters operate as checks on the risks and consequences of a non-independent expert being appointed by a party to the arbitration. These mechanisms do not have the same degree of force in relation to a tribunal-appointed expert.

9.47  In many cases, the evidence to be presented by the tribunal-appointed expert will be the only evidence that the tribunal has before it on a particular issue. In the majority of those cases the tribunal will therefore rely on that evidence in reaching its determination. The parties need to be in a position to trust the expert’s objectivity and impartiality. Early provision of a statement of independence and an opportunity to raise objections on the basis of a lack of independence prior to the expert being appointed are extremely important parts of the process for appointment of a tribunal-appointed expert.

9.48  Article 6 requires the proposed tribunal-appointed expert to provide a single statement of that expert’s independence from the parties, their legal advisers, and the tribunal—the statement of independence. This requirement is in contrast to the position under Article 5, which requires a party-appointed expert to provide a statement of his or her present or past relationship with any of the parties, their legal advisors, and the tribunal²⁹ in addition to a ‘statement of independence from the Parties, their legal advisers and the Arbitral tribunal’.³⁰ The reason for the difference in approach is unclear.³¹ There is nothing in the Commentary on the IBA Rules to explain the reason for the additional requirement contained in Article 5, although it may be directed at achieving as much transparency as possible around the nature of any pre-existing relationship between a party and its appointed expert. In our view, an express requirement of transparency about the nature of any relevant pre-existing relationship is equally desirable in relation to a tribunal-appointed expert.

9.49  Article 6.2 requires a statement of independence, but make no reference to impartiality, even though in some cases applicable institutional rules or local arbitration law may impose this requirement. This position has attracted some criticism and debate, as has the requirement (introduced for the first time in the 2010 IBA Rules) that the expert declare themselves independent of the parties’ legal advisers. These matters are addressed in more detail in Chapter 8.³²

9.50  Article 6.2 sets out the procedure that is to be followed when, following delivery of the expert’s description of qualifications and statement of independence, a party wishes to raise an objection to the proposed appointment.

9.51  Under Article 6.2, the tribunal is to set a deadline by which any objections are to be raised and, if an objection is raised, the tribunal should decide ‘promptly’ whether to accept the objection.

9.52  In practice, there may be some dialogue between the tribunal, parties, and the proposed expert in the event an objection is received. The tribunal may wish to ask questions of the expert in relation to the basis of objection, or to invite submissions from the non-objecting party. Provided there is full transparency around such communications, there is nothing wrong in these (or other appropriate) steps being taken. However, the tribunal is likely to want these matters addressed and resolved as soon as possible so that there is no delay to progress in the arbitration. If the objection is upheld, the tribunal will need to find another suitable expert. The requirement in the IBA Rules that the tribunal rule on an objection promptly is consistent with the desirability for speed in relation to these matters.

9.53  It is important that a party act promptly in the event that it has concerns about the expert’s qualifications or independence. It must make known its objection by the deadline laid down by the tribunal. It will not be able to rely on those matters as a basis for objection after that deadline has passed. Only circumstances not known to the objecting party at the date of the deadline may be relied upon as a basis for objection at a later date. This is made clear by the following new provision in Article 6.2 not present in the 1999 IBA Rules:

After the appointment of a Tribunal-Appointed Expert, a Party may object to the expert’s qualifications or independence only if the objection is for reasons of which the Party becomes aware after the appointment has been made.³³

9.54  The rationale for this addition was to prevent belated and/or tactical challenges to the appointment of an expert intended to derail or delay the process. The parties are required to either raise their objections before the appointment or to be deemed to accept the position unless new circumstances come to light on which a later objection may be based.

(p. 340)

• View full-sized figure

Figure 9.1  Flowchart for Appointment of a Tribunal-Appointed Expert

9.55  Article 6.3 sets out the procedure by which a tribunal-appointed expert may obtain information from the parties that the expert needs to prepare the expert evidence that he or she has been asked to provide.

9.56  Whatever volume of information is provided to the expert with the terms of reference it is almost inevitable that the expert will have questions and/or will require further information when s/he comes to consider the issues upon which s/he must opine. In the event that a party objects to provision of the requested information, Article 6.3 confirms the mechanism by which that objection is to be resolved and the steps to be taken where a party refuses to make the information available.

9.57  The formal procedure for obtaining information set out in Article 6.3 is necessary for a number of reasons. A tribunal-appointed expert does not enjoy the same proximity of relationship to the parties as a party-appointed expert. Where the latter is used, the parties will take all appropriate steps to ensure that ‘their’ expert is provided with all necessary documents, goods, and samples. The same facility is not available to a tribunal-appointed expert who is, and must remain, wholly independent of any party to the dispute. In addition, if the tribunal-appointed expert is to retain the confidence of the parties, it is desirable to maintain transparency around the making of requests for information by the expert, and the nature of information provided by a party in response to such request.

9.58  The provisions of Article 6.3 may be supplemented by measures agreed by the parties in the terms of reference provided under Article 6.1. As mentioned, it is desirable that the tribunal and the parties agree a communication protocol to ensure transparency of process. Ideally, the expert should not communicate with a party without the other party being copied on that communication, and all requests for information and access should be made in writing and copied to all parties.

9.59  Article 6.3 gives the tribunal-appointed expert the same authority as the tribunal to request information/access ‘to the extent relevant to the case and material to its outcome’. As mentioned elsewhere, the benchmark of relevance and materiality constitutes the gold standard for introduction of evidence under the IBA Rules. However, Article 6.3 also refers expressly to the application of Article 9.2 of the IBA Rules pursuant to which a party may object to, or the tribunal may exclude, material from the arbitration on a number of grounds. Those grounds include a lack of relevance and materiality.³⁴ In our (p. 342) view, the inclusion of the additional express reference to the benchmark of relevance and materiality in connection with a request made by a tribunal-appointed expert highlights that the expert should consider carefully whether what is being requested meets that benchmark. It is sensible to flag this matter in the terms of reference so that the expert is aware that he or she may have to provide a justification for the request by reference to this standard. Chapter 6 provides more in-depth discussion on the terms ‘relevant to the case’ and ‘material to its outcome’.³⁵

9.60  Under Article 6.3, the tribunal-appointed expert may ask a party to the arbitration to provide:

1. (a)  information;

2. (b)  access to any documents, goods, samples, property, machinery, systems, and/or processes; or

3. (c)  access to site for inspection.³⁶

9.61  The tribunal-appointed expert may make the request directly to a party to the arbitration without prior reference to the tribunal. However, as mentioned, it is desirable that the request be copied to the tribunal and to the other parties. The application of Article 9.2 of the IBA Rules (anticipated by Article 3.3) depends upon the parties being aware of the requests made.

9.62  Practice varies in relation to the ability of a tribunal-appointed expert to address a request for information direct to a party and different arbitration rules approach the issue in different ways. For example, under some rules, any request for additional information must be made by the tribunal rather than by the expert themselves. Article 21.3 of the LCIA Rules provides that:

The Arbitral Tribunal may require any party at any time to give to such expert any relevant information or to provide access to any relevant documents, goods, samples, property, site or thing for inspection under that party’s control on such terms as the Arbitral Tribunal thinks appropriate in the circumstances.³⁷

9.63  Other rules impose an obligation on the parties to produce documents and information requested but are silent as to who can request those materials. An example of this approach is Article 29(3) of the UNCITRAL Rules which provides that:

The parties shall give the expert any relevant information or produce for his or her inspection any relevant documents or goods that he or she may require of them. Any dispute between a party and such expert as to the relevance of the required information or production shall be referred to the arbitral tribunal for decision.³⁸

(p. 343) Although ‘as he or she may require of them’ might be read as meaning a request from the expert, the position is by no means clear.

9.64  A third approach, adopted in Article 6.3 of the IBA Rules, is to make express provision for a direct request to be made by the expert to a party.³⁹ Article 6.3 goes as far as to say that the authority of a tribunal-appointed expert to request such information or access ‘shall be the same as the authority of the Tribunal’.

9.65  A party has the right to object to a request for information/access made by a tribunal-appointed expert. The objection may be made on grounds that the information requested is not relevant to the case or material to its outcome, or on any of the other grounds set out in Article 9.2.⁴⁰

9.66  It appears from the wording of Article 6.3 that, if the expert accepts the objection, that is the end of the matter. However, where the objecting party and the expert disagree as to the ‘relevance and materiality or appropriateness’ of the request the disagreement will be decided by the tribunal ‘in the manner’ provided in Articles 3.5 to 3.8 of the IBA Rules. It is assumed that the reference to ‘appropriateness’ is a shorthand for the grounds of objection available under Article 9.2.⁴¹

9.67  Articles 3.5 to 3.8 of the IBA Rules set out a procedure by which a party objection to a request for production of documents by another party may be resolved or determined by the tribunal, including provision for the material subject to the objection to be reviewed by another independent third party where this is necessary to establish the validity of the objection and the tribunal does not consider it appropriate to review the material itself. The provisions of Articles 3.5 to 3.8 are dealt with in Chapter 6 at 6.215–6.280. It is not clear whether, in the context of Article 6.3, those provisions are to be read simply as substituting the tribunal-appointed expert for the ‘Party [submitting] a Request to Produce’ or more literally. We suggest that the substance of any objection to a request made by a tribunal-appointed-expert is properly to be resolved between the parties to the dispute, or absent that, to be determined by the tribunal. Accordingly, any objection to an expert’s request should be delivered to the tribunal, and be copied to all other parties and to the expert. The parties should consult and endeavour to reach an agreed position on whether the information/access requested is or is not relevant and material, or whether another (p. 344) ground for objection is made out. If the parties cannot reach agreement, then the matter will be determined by the tribunal. This is consistent with the tribunal being the final arbiter of what material may be introduced into the arbitration.

9.68  Article 6.3 establishes the right of the parties and their representatives to receive the same information that the tribunal-appointed expert receives from another party, and to attend any inspection that the expert conducts. This right is repeated in Article 6.5, and is uncontroversial.⁴² For the process to be fair, each party must be given the same opportunity as the expert to have the information and access in order that it may draw its own conclusions. For example, the other party may consider the information/access to be incomplete and therefore misleading.

9.69  Where the information requested involves trade secrets or other confidential commercial information, the party in possession may need to consider seeking confidentiality protections from the tribunal. Article 9.4 provides a mechanism for such an application.⁴³

9.70  If the request for information/access is made to a party and that request is not withdrawn or overruled by the tribunal, the party asked to provide the information or access is obliged to comply with the request. However, in practice, where the party refuses to do so there is little that the tribunal-appointed expert, or the tribunal, can do to compel provision of what has been requested.

9.71  One possible sanction is for the tribunal to draw an adverse inference against the non-providing party. Article 9.6 of the IBA Rules grants the tribunal express power to do so where a party has not objected to a request for evidence made by the other party or the tribunal has ordered that it should be produced:

If a Party fails without satisfactory explanation to make available any other relevant evidence, including testimony, sought by one Party to which the Party to whom the request was addressed has not objected in due time or fails to make available any evidence, including testimony, ordered by the Arbitral Tribunal to be produced, the Arbitral Tribunal may infer that such evidence would be adverse to the interests of that Party.

(p. 345) 9.72  Although such provision makes no reference to a request for information/access made by a tribunal-appointed expert it may be read as applying to circumstances where a tribunal has overruled a party objection and made an order that information be provided to the expert. Other provisions of Article 6.3 support this reading. In order to assess whether an adverse inference may be drawn, and what that inference might be, the tribunal will need to understand the nature of the information withheld and what impact that information might have had on the evidence of the tribunal-appointed expert. Article 6.3 requires the expert to include in the expert report a description of the effect of the non-compliance on the determination of the specific issue to which it relates.

9.73  In our view, it would in any event be open to the tribunal to draw an adverse inference in appropriate circumstances pursuant to its general powers under Articles 9.1, 9.5, and 9.6. The use of adverse inferences is dealt with in more detail at Chapter 12 at 12.357–12.386.

9.74  Article 6.4 sets out requirements for the content of the report prepared by the tribunal-appointed expert. In some instances, these mirror the requirements that apply to the (p. 346) report of a party-appointed expert dealt with in detail in Chapter 8. However, as mentioned, Articles 5 and 6 have slightly different issues to tackle. This is why the requirements as to the content of the expert’s report in each case are tailored to the role of either tribunal-appointed or party-appointed expert. Where a provision is the same as that under Article 5 in relation to the report of a party-appointed expert, we make no further comment on the position under Article 6. Where the wording differs, the difference is addressed.

9.75  As a further preliminary point, it is worth noting those requirements for the content of a party-appointed expert that are missing from Article 6.4, specifically:

1. (a)  Article 6.4 does not contain a requirement that the expert report include a statement of the expert’s independence from the parties, the parties’ legal advisors and the tribunal as is required by Article 5.2(c). This requirement is redundant in Article 6 because a statement of independence should have been provided prior to appointment in accordance with Article 6.2.

2. (b)  Another difference is that a tribunal-appointed expert is not required to include ‘a description of the instructions pursuant to which he or she is providing his or her opinions and conclusions’ as is required in relation to a party-appointed expert by Article 5.2(b) introduced in the current 2010 version of the IBA Rules.⁴⁴ The parties will already be aware of the instructions provided to the tribunal-appointed expert by means of the terms of reference copied to the parties pursuant to Article 6.1.

9.76  Finally, the additional requirement found in Article 6.3 that the expert should record in the report any non-compliance by a party with a request for information, and the effect of that non-compliance on the expert’s determination, should also be borne in mind when considering a report prepared by a tribunal-appointed expert.

9.77  Article 6.4 is drafted as mandatory requirement—‘The Expert Report shall contain . . . ’. If the application of the IBA Rules has been agreed or ordered, reports submitted by a tribunal-appointed expert must comply with the requirements set out in Article 6.4. Ideally, the terms of reference given to the expert under Article 6.1 will have highlighted those provisions for the expert’s attention.

9.78  The IBA Rules do not provide any sanction for non-compliance with the requirements in Article 6.4. In practice, tribunals are likely to approach this on a case-by-case basis.⁴⁵ If the non-compliance is material, the tribunal is likely to direct the expert to remedy the omission. The expert has been appointed by the tribunal and should accede to directions given by the tribunal after consultation with the parties.

(p. 347) 9.79  For example, the tribunal may have noticed a deficiency in the evidence itself or it may have been alerted to it by one or more of the parties. In circumstances where, on a particular issue, the tribunal has only the evidence of the tribunal-appointed expert, it is extremely important that such evidence be complete, that the expert set out the facts relied on in giving the opinion expressed in the report, and that the methodology and technical materials that the expert used in reaching his or her conclusions are provided in order that the tribunal may understand it, and so that each party may challenge during presentation of its case any part of the report with which it takes issue. Any deficiency in relation to these aspects of content will need to be remedied.

9.80  In theory, an available alternative approach is for the tribunal to admit the non-compliant expert report into evidence with the caveat that the omissions may affect the weight attached to it by the tribunal. However, while this approach may work in relation to party-appointed expert evidence where there may be other party-expert evidence on the same issue available to fill the gaps, it is unlikely to be satisfactory where there is a single tribunal-appointed expert and the parties have not instructed their own experts.

9.81  Article 6.4 is useful in providing a form of checklist for the content of the expert report to be produced by the tribunal-appointed expert. The requirements in Article 6.4 reflect good practice in relation to the form and content of an expert report.

9.82  Article 6.4(a) requires the report to include the expert’s name and address and a description of his or her background, qualifications, training, and experience. This requirement is similar to that in Article 5.2 of the IBA Rules with the omission of a statement of independence.⁴⁶ Although the expert should have already provided a description of his or her qualifications pursuant to Article 6.1, the requirement at Article 6.4 to include in the report the much broader description of ‘background, qualifications, training and experience’ should pick up the full spectrum of attributes that qualify that individual to provide an expert opinion.

(p. 348) 9.83  Article 6.4(b) provides that the expert report set out the facts upon which the expert is basing his or her opinion. This requirement is the same as that appearing in Article 5.2(d) in relation to party-appointed experts. The same considerations will apply.⁴⁷

9.84  Article 6.4(c) is an important provision stating the core requirement that the expert set out in the report the expert’s opinions and conclusions on the matters s/he has been asked to address. It is these opinions/conclusions upon which (subject to challenge from the parties) the tribunal is likely to rely in reaching a determination.

9.85  A second requirement of Article 6.4(c) is that the report must contain a description of ‘the methods, evidence and information used in arriving at the conclusions’. This information is necessary to put the other party and the tribunal in a position where they can meaningfully evaluate and/or question the expert evidence presented.

9.86  Lastly, Article 6.4(c) contains express provision that the expert report must be accompanied by any documents on which the expert relies that are not already on the record.

9.87  These requirements are the same as those appearing in Article 5.2(e) in relation to party-appointed experts. Similar considerations will apply.⁴⁸

9.88  Where the version of the expert report delivered to the tribunal is a translation, Article 6.4(d) requires the expert to disclose in the report the original language of the report and the language in which the expert anticipates giving oral testimony. These requirements are the same as those appearing in Article 5.2(f) in relation to party-appointed experts and the similar considerations will apply in relation to practical application of what is needed in order to comply with them.⁴⁹ However, in relation to tribunal-appointed experts, this information should (in most cases) (p. 349) come as no surprise to any of the parties. The question of whether the expert is able to present evidence in the language of the arbitration is something that is likely to have been explored during the appointment process. The size of the pool of suitably qualified experts may influence whether the tribunal selects an expert able to give evidence in the language of the arbitration over one that is not. An interesting question arises as to whether the language skills (or lack of them) of a tribunal-appointed expert forms part of the ‘qualifications’ to be disclosed to the tribunal and the parties under Article 6.2, and in relation to which a party may raise an objection under that provision.

9.89  Articles 6.4(e), (f), and (g) require the report to contain an affirmation of belief in the opinions expressed, the signature of the tribunal-appointed expert (with date and time of signature), and, where there is more than one signature, a statement explaining which parts of the report may be attributed to each signatory. These provisions are in identical terms to those appearing in Article 5.2(g), (h), and (i) in relation to the report of a party-appointed expert.⁵⁰

9.90  Article 6.5 makes express provision for the parties to receive a copy of the expert report and to have a right of response to that report prepared by the tribunal-appointed expert.

9.91  Article 6.5 is concerned with natural justice, particularly the right of a party to have reasonable notice of evidence that may be relied on in the arbitration, and to be able to prepare and present its own case.⁵¹ It comprises two main elements. The first is a right of access to the report and materials on which the expert prepared his or her evidence. The second is the right to respond to that evidence.

9.92  In summary, each party to the arbitration must be provided with:

1. (i)  a copy of the report produced by the tribunal-appointed expert;

2. (ii)  all of the materials that the expert has examined in the course of preparing the report; and

3. (iii)  any correspondence that has passed between the tribunal and the expert.

9.93  Each party is entitled to respond to the expert report by means of submissions, a witness statement, or an expert report prepared by an expert instructed by the party.

9.94  Article 6.5 suggests that the tribunal is to act as a conduit for provision of the expert report to the parties, and for provision of the parties’ responses (if any) to the expert. In practice, if the parties have agreed a communication protocol as part of the terms of reference for the expert under Article 6.1, this may provide for delivery of correspondence and materials to all participants simultaneously. However, it is still up to the tribunal to take the lead in guiding the participants through the various steps described in Article 6.5, even if some or all of these have been anticipated and laid out in the terms of reference.

9.95  Article 6.5 is silent as to the point at which the expert’s report is to be provided by the tribunal to the parties, but we suggest that it should be delivered to them as soon as possible after receipt by the tribunal. As mentioned, a copy may have been sent by the expert direct to the parties at the same time as it was sent to the tribunal. The tribunal may nonetheless wish to write to the parties to note this and to remind them of any dates agreed by which party responses to the report must be provided. If there are no dates ordered or agreed in the existing procedural timetable then the tribunal will need to indicate a date by which responses should be delivered.

(p. 351) 9.96  In addition to seeing the report it is important that the parties have full transparency around the facts and materials relied upon by the expert in reaching his or her conclusions. Without this information the parties cannot properly evaluate the quality of the evidence and decide whether they wish to take issue with anything contained in the report. Like Article 6.3, Article 6.5 makes provision for the parties to have the right to see the categories of material described in Article 6.5 that the expert has ‘examined’ in reaching his or her conclusions.

9.97  The categories of material referred to in Article 6.5 are broad. They comprise ‘any information, Documents, goods, samples, property, machinery, systems, processes or site for inspection’. ‘Documents’ is itself a defined term in the IBA Rules and, taking this into account, it is very unlikely that any material the expert has seen would fall outside of the description in Article 6.5.

9.98  Article 6.5 also states that the parties are entitled to examine ‘any correspondence between the Tribunal and the Tribunal-Appointed Expert’. This provision suggests that ex parte correspondence may have taken place between the tribunal and the expert. On this basis, it appears that ex parte correspondence is permissible, subject to the safeguard contained in Article 6.5 giving the parties the right to examine that correspondence. We suggest that it may be prudent for parties to make an express request for sight of such correspondence where this is not provided for by means of an agreed communication protocol.

9.99  The possibility of ex parte communications between a tribunal and an expert is not yet ruled out in the practice of international arbitration. For example, until very recently the HKIAC Rules included express provision at Article 25.1 that ‘The arbitral tribunal may meet privately with any tribunal-appointed expert’.⁵²

9.100  On the other hand, as mentioned, much may depend on what might have been agreed between the parties and the tribunal during initial consultation on appointment of the expert, and the individual preferences of the particular tribunal. For example, in a survey on this issue, respondents from Spain indicated that they had experience of a tribunal making an express direction that there should be no ex parte communications between tribunal and expert (as well as that the expert should not attend the tribunal’s deliberations).⁵³

9.101  Article 6.5 makes express provision for the parties to have an opportunity to respond to the report produced by the tribunal-appointed expert. This is unsurprising and reflects accepted practice in international arbitration.⁵⁴ In the interests of fairness and natural justice the parties must have an opportunity to present their views on the evidence so that they may, where necessary, point out any errors or omissions and/or have the opportunity to present reasons why the tribunal ought not to accept the conclusions of the expert. This is particularly important where the tribunal is relying on the evidence of a single tribunal-appointed expert, rather than weighing the evidence from ‘competing’ party-appointed experts.

9.102  Consistent with the above position, the commentary to the rules states that:

The Working Party and the Subcommittee believed strongly that parties should know what the arbitral tribunal is being told by a Tribunal-Appointed Expert and should have an opportunity to rebut his or her conclusions.⁵⁵

9.103  Other guidelines on the use of tribunal-appointed experts also stress the need for a party to have a right of response. For example, Practice Guideline 10 of the Chartered Institute of Arbitrators (Guidelines on the Use of Tribunal-Appointed Experts, Legal Advisers and Assessors) recommends that:

[I]f the tribunal does decide to appoint an expert legal adviser or assessor the procedure to be followed must be closely defined in an order made by the tribunal at or about the stage of the appointment. Section 37 leaves the details of that procedure to the discretion of the tribunal save in one respect, that is, that any information, opinion or advice offered by any person appointed by the tribunal must be communicated to the parties and the parties must be given a reasonable opportunity to comment on it.⁵⁶

9.104  Under Article 6.5, a party must exercise its right to respond by a date to be determined by the tribunal. Article 6.5 describes the form such a response may take. Each party may choose to respond:

• •  in a submission;

• •  through a witness statement; or

• •  by means of an expert report from a party-appointed expert.⁵⁷

(p. 353) In our view, it is not intended that the parties have to make an election between these forms of response. In some instances, it may be necessary or appropriate for a party to use a combination of them.

9.105  Subject to any tribunal direction or agreement to the contrary, the wording of Article 6.5 suggests that the response should be sent to the tribunal, who will then pass it on to the expert. Although not provided for in Article 6.5, the tribunal may consider it appropriate in some cases for there to be a further round of expert evidence.

9.106  An alternative approach to inviting responses to a completed expert report is for the tribunal to instruct the expert to submit a report in draft and for the tribunal to then invite the parties to comment on the expert’s provisional findings. This allows the expert to take the parties’ comments into account when finalizing the report. The advantage of this is that it may allow errors or omissions to be picked up and corrected before the report is issued in final form. A significant drawback is that it may result in protracted communications between all participants and a potential dilution of the evidence. In one reported case the tribunal departed from the guidelines laid down in Article 6.5 and adopted a procedure providing for the expert to submit a draft report so that the parties could request additional explanation or justification for the findings made. Although the tribunal saw this step as enhancing the efficiency of the process by avoiding unnecessarily long and complicated expert reports, it unfortunately led to a challenge to the expert and to the admissibility of the report.⁵⁸

9.107  Article 6.5 addresses the attendance of a tribunal-appointed expert at an evidentiary hearing.

9.108  In line with other provisions of the IBA Rules, a tribunal-appointed expert who submits an expert report is only required to appear at the evidentiary hearing if a party or the tribunal requests that attendance. If no such request is made, there is no requirement that the expert attend.

9.109  Article 6.6 states expressly that, where an expert does attend an evidentiary hearing, the expert may be questioned by the tribunal, or by the parties or their appointed experts.

9.110  This is an important provision. It is essential that each party be given an opportunity to question the expert in order to test his or her evidence. Although the parties will have had an opportunity under Article 6.5 to respond to the expert evidence, the expert may not have accepted the points made and counsel for the parties will wish to pursue those matters in cross-examination. It is also useful for the tribunal to see the evidence tested. In most cases, the tribunal will only form a final view as to the weight to be attached to expert evidence after it has had the opportunity to hear the expert under questioning from the parties.

9.111  The scope of the permitted questioning is limited to issues arising out of the expert’s report or a party’s response to that report delivered pursuant to Article 6.5. The Commentary on the IBA Rules explains that this provision is intended to ensure that the tribunal-appointed expert knows in advance the subjects on which s/he might be questioned, in order to prepare his or her responses and avoid the possibility of an adjournment being required as a result of new issues being put to the tribunal-appointed expert for the first time at the hearing.⁵⁹

9.112  The express provision for a party-appointed expert to question the expert is interesting. While there may be advantages to an expert being questioned by another expert in the same discipline, the general practice in international arbitration is for cross-examination of an expert to be undertaken by counsel. An expert qualified in a discipline other than law may have a different skill set to that of an experienced advocate.

9.113  That said, where witness conferencing⁶⁰ is being employed by the tribunal, a discussion between a tribunal-appointed expert and any party-appointed experts qualified in the same discipline may be a useful way of assessing the evidence. There appears to be (p. 355) general acceptance that witness conferencing involving a tribunal-appointed expert is permitted under the provisions of Article 8 of the IBA Rules.⁶¹ We agree with that view. Of course, witness conferencing is only possible where there is more than one expert on the same issue.

9.114  Article 6 does not provide any consequences if a tribunal-appointed expert fails to attend the hearing if so requested. This is in stark contrast with the position of a party-appointed expert whose failure to appear will, under Article 5.5 of the IBA Rules, result in the expert report being disregarded by the tribunal unless it considers that there are exceptional circumstances that warrant its inclusion. It is not clear why the approach is different with respect to different types of experts. One possible explanation is that application of the Article 5 provision to the tribunal-appointed expert may leave the tribunal with no expert evidence at all, while in case of party-appointed experts, at least the tribunal can rely on the evidence of the other party’s expert who has appeared.

9.115  If the parties do not have an opportunity to cross-examine the tribunal-appointed expert, reliance by the tribunal on that evidence alone could be a failure of due process (or at least give one or other of the parties an opportunity to argue that it is). When weighing the evidence of a non-attending expert, the tribunal will have to take into account the responses to the report of the tribunal-appointed expert filed by the parties under Article 6.5, any reply to those responses made by the expert, and the fact that the expert was not available at the evidentiary hearing to answer further questions on the disputed issues.

9.116  In practice, the non-attendance of a tribunal-appointed expert is likely to be rare. In addition to failing to meet the requirements of Article 6.6, it is also likely to constitute a breach of the expert’s retainer with the tribunal and may have financial consequences for the expert. Where there are bona fide reasons for the expert not being able to attend, the tribunal may also decide that it should adjourn the hearing, or at least that portion concerned with the issues addressed by the expert, until a later date.

9.117  The IBA Rules are silent as to what further role (if any) the expert may play at the hearing, eg if members of the tribunal should be permitted to have the expert sit with them as an adviser during questioning of any experts of the same discipline appointed (p. 356) by the parties, or when counsel for the parties are making submissions on the evidence of the tribunal expert. We are aware of cases where the tribunal has invited a tribunal-appointed expert to sit with the tribunal throughout the evidentiary hearing. We suggest that it is prudent for a tribunal considering such a step to first canvass it with the parties or, at the very least, to make known the intended scope of the expert’s intended involvement so as to address as far as possible any concerns that the parties may have about the expert assuming a decision-making role (which is clearly prohibited).

9.118  Article 6 does not contain any reference to the attendance of a tribunal-appointed expert at tribunal deliberations or other meeting with the tribunal at which the parties are not present. However, nor does it contain an express prohibition on such attendance.

9.119  The presence of a tribunal-appointed expert in private meetings or at tribunal deliberations has advantages and disadvantages. On the one hand, the tribunal may benefit from expert assistance. The presence of the expert may help avoid any errors when the tribunal comes to consider the expert evidence and the parties’ submissions on the evidence. Meeting with the expert and the parties may be less useful. The tribunal may be hesitant about discussing particular issues with the expert in an open way for fear of giving an appearance of bias. In addition, the parties may wish to intervene unnecessarily so as to make such meetings time-consuming and/or counter-productive.

9.120  On the other hand, the Article 6 mechanism must achieve the right balance between the tribunal’s need for assistance on expert issues and the rights of the parties. The tribunal must not become so dependent on the expert that the case is effectively decided by the expert rather than the tribunal. For this reason, the parties may have justified concerns if the tribunal-appointed expert attends deliberations and expresses his or her views in the absence of the parties.

9.121  We suggest that there are serious risks associated with allowing the expert to be present in meetings with the tribunal without the parties also being present. Article 6 allows a tribunal to seek assistance from an expert, but does not allow the tribunal to delegate its decision-making function.⁶² If a tribunal were to listen to additional input from the expert during a meeting or deliberations without giving the parties the opportunity to comment on that input before taking it into account, this would undoubtedly breach rules of natural justice. While the tribunal may want the expert present to walk them through the available evidence, it would be very easy for the line between explanation and comment to be crossed.

(p. 357) 9.122  Unsurprisingly, there have been instances where national courts have found that ex parte meetings between a tribunal and a tribunal-appointed expert amount to an irregularity. In Hussmann (Europe) Ltd v Al Ameen Development & Trade Co & Ors.,⁶³ the applicant (HCN) challenged the award on the basis of alleged serious procedural irregularities including the fact that—without the parties being present—the tribunal had met with a tribunal-appointed expert on Saudi law to discuss the expert’s report. Although what had occurred was not sufficient to sustain a proper challenge to the award, Mr Justice Thomas found that the meeting breached a provision of English arbitration law that required a tribunal to give the parties a reasonable opportunity to comment on ‘information, opinion or advice’ offered by a tribunal-appointed expert. In his judgment, Thomas J said that:

Given that the pleadings raised no issues of Saudi law and that it was for the parties to allege that foreign law differed from English law, the tribunal should have followed the course of asking the parties whether there were any points where the law of Saudi Arabia differed from the law of England and Wales or to have itself raised with the parties specific points on which it might need assistance. However there was no irregularity in the tribunal instructing its own expert since the parties had left the way in which the expert was to be instructed to the tribunal.⁶⁴ The private meeting with the expert to discuss his draft report was contrary to s. 37(1) (b) of the 1996 Act and failure to inform the parties of it was an irregularity.

[ . . . ]

The point was taken that in the meeting with Dr Al-Qasem, the tribunal was not taking evidence and so the provisions of s. 37(1) (b) did not apply; I do not agree. They were plainly discussing with him the law of Saudi Arabia and the content of his report; in my judgment the provisions of the section were applicable to this meeting at which his evidence was discussed.⁶⁵

9.123  Thomas J went on to make some further general observations in relation to discussions between a tribunal and tribunal-appointed expert at which the parties were not present. He said that:

A tribunal should generally not hear evidence in the absence of the parties.

I agree with the observation of Professor Merkin in his work on arbitration at para. 13.46(e): ‘ . . . consultation with the experts should not take place after the close of the hearing or otherwise in the absence of the parties as this deprives the parties of their right to comment’.⁶⁶

9.124  While the IBA Rules do not expressly rule out ex parte meetings with a tribunal-appointed expert, a tribunal must be vigilant about protecting each party’s right to (p. 358) present its case and to know the evidence against it. The tribunal should not rely on views and conclusions of the expert about which the parties have had no opportunity to comment.

9.125  As mentioned, a primary area of concern relating to the use of a tribunal-appointed expert is that the tribunal may delegate its decision-making function to the expert. Article 6.7 addresses this problem and appears to be a reminder to the tribunal that it should not place undue reliance on the expert report produced by a tribunal-appointed expert without reference to the other available evidence and the circumstances of the case.

9.126  Furthermore, it highlights that the weight to be attached to the expert evidence on the facts of the case is to be assessed by the tribunal. The tribunal must not delegate its mandate to determine the dispute and the tribunal is not bound by the expert’s findings. It is the role of the tribunal to assess the evidence. In exceptional circumstances, the tribunal may decide to place little or no reliance on the evidence of the tribunal-appointed expert, or it may prefer the evidence of a party-appointed expert over that of its own expert. For example, it might decide to disregard the evidence where:

• •  there are rebuttal reports from two or more party-appointed experts in which those experts reach the same conclusion, being a conclusion that is different to that of the tribunal-appointed expert; and/or

• •  the conclusions of the tribunal-appointed expert are based on assumptions/conditions that are not borne out by the facts; and/or

• •  the expert report produced by the tribunal-appointed expert contradicts the majority of the evidence on the record and common sense.