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Max Planck Encyclopedia of International Procedural Law [MPEiPro]


Makane Moïse Mbengue, Rukmini Das

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2023. All Rights Reserved.date: 28 March 2023

Expert evidence — Arbitration

Published under the direction of Hélène Ruiz Fabri, with the support of the Department of International Law and Dispute Resolution, under the auspices of the Max Planck Institute Luxembourg for Procedural Law.

A.  Introduction

International courts and tribunals are increasingly faced with numerous technical, extra-legal issues in disputes before them with entire disputes often hinging on technical questions. This of course mirrors a growing number of international legal instruments today governing issues of science, the environment, and other technical fields. Examples include the United Nations Framework Convention on Climate Change, the Convention on Biological Diversity, and the World Health Organization’s Framework Convention on Tobacco Control. As a result of disputes becoming more technical, the international dispute settlement system is witnessing a gradual alteration from a procedural viewpoint. Though not a new aspect of international dispute settlement, the expert is increasingly involved in the international judicial process as a tool to assist the adjudicator in decision-making and playing varying roles in various disputes. This is especially the case in scientific issues that frequently arise today in international disputes (Dispute). Disputes on matters as diverse as determination of land and maritime boundaries, protection of human, animal, and plant health, and quantification of damages all raise complex factual issues that require resolution. The assistance of experts in such situations can greatly assist in resolving such conflicts so it is important to understand the special nature of scientific evidence (Scientific Evidence: International Adjudication).

2  It is not always easy to discern the extent of the effect of scientific evidence on international judicial decisions. In matters in which scientific expertise is crucial to the issues in dispute, strong legal submissions will not suffice on their own to win the case; science-based evidence, its presentation, and the authority of individual experts will be central to a court’s decision (Sands, 2010, 155). Assuming this to be true, the procedure for handling scientific evidence and the experts that bring this evidence becomes even more important (Miles, 2014, 160–61). Inextricably linked with and a precursor to assessing scientific evidence is scientific fact-finding. While fact-finding is an indispensable component of the judicial function in a court of first instance, ‘scientific fact-finding’ is a unique category of fact-finding. Its uniqueness lies in its distinctive features that include a combination of judicial reasoning and fact-finding (Mbengue, 2016, 532). Establishing scientific facts should take recourse to ‘accepted fundamental laws and facts of nature known through the methods of science’ (d’Aspremont and Mbengue, 2014, 246). Moreover, scientific fact-finding often involves discovery of the ‘uncertain fact’ (Mbengue, 2016, 532), another distinctive feature which calls for the involvement of experts. In applying the judicial mind to scientific data—that is, facts requiring specialized knowledge or skill—an expert, whether an individual or organization, can help the tribunal in finding the relevant facts or help the adjudicator in understanding the meaning of these facts and their relevance to the proper application of the law to the scientific facts (Simma, 2012, 232).

Having provided an overview of the need for expertise in international decision-making, this entry will first examine what is meant by the term ‘expert’ in the context of international dispute settlement (see sec B below). Given the wide-ranging meanings attributed to this term, the next part of the entry explores the various types of experts one may encounter in an international judicial proceeding (sec C). In doing so, reference will be made to a few prominent international dispute settlement for a and systems. Thereafter, the international legal framework, rules, and practice governing the recourse to experts will be briefly examined also in the context of a few well-known international fora (sec D). To better understand the roles played by different kinds of experts, the next section will highlight the key differences among their various roles (sec E). Finally, the concluding section evaluates the present status of the expert on the international judicial plane (sec F).

B.  Definition

None of the treaties, statutes, or rules of international decision-making bodies or any other international legal instruments mentioning an ‘expert’ defines the term. Only under the Headquarters Agreement for the International Tribunal for the Law of the Sea (International Tribunal for the Law of the Sea (ITLOS)), is an ‘expert’ given the meaning of a person called at the instance of a party to a dispute or at the instance of the Tribunal to present testimony in the form of expert opinions, based on special knowledge, skills, experience, or training (Art 1 (I) Agreement between the International Tribunal for the Law of the Sea and the Federal Republic of Germany regarding the Headquarters of the Tribunal). There are no widely accepted definitions of who constitutes an expert, or what constitutes expertise (Ericsson and others, 2006). Put simply, an expert is ‘one who is very skilful and well-informed in some special field’ (Ericsson and others, 2006, 3). The test for expertise may, however, differ in various fields. Thus, it is difficult for non-experts to identify experts in other domains and as a result researchers rely on peer-nominations by professionals in the same domain (Ericsson and others, 2006, 4). However, people recognized by their peers as experts do not always display superior performance on domain-related tasks. There are several domains where experts disagree and make inconsistent recommendations for action. For example, it has been found that assessments by expert auditors differ more from each other than the assessments of less experienced auditors (Bédard, 1991, 198).

These considerations are useful not only for understanding the requirements that qualify a person to be an expert but also shed some light on the possible means of selecting an expert to assist in judicial decision making. Notwithstanding the general understanding of what it means to be an expert, it is important to contextualize what is meant by this term in the international judicial context. As noted by the International Court of Justice (ICJ), and clearly applicable in any judicial context, the purpose of an expert’s opinion rendered in a dispute is to ‘assist the Court in giving judgment upon the issues submitted to it for decision’ (Continental Shelf, Tunisia/Libya, 1982, 228). According to former President Spender of the ICJ, a person can be expert in any field in which they reveal a special knowledge ‘far in excess of that which is normally held by a lay person’ (South West Africa, Ethiopia v South Africa, Liberia v South Africa, 1966, 515). Consequently, while experts express their opinion on certain facts of a specialized nature based on their specialised knowledge, it is not their task to testify to facts or alleged facts (Mačák, 2019, 1276).

Based on existing legal provisions and practice, and taking into consideration the various means of involvement of experts in international disputes, which will be elaborated on below, an expert may be thus defined as a person or group of persons or institution or organization, whether appointed by a party to a dispute or the court or tribunal or a combination of the two, to provide an opinion on a subject in which the expert has in-depth knowledge gained through years of study and/or experience.

The expert may be acting as counsel for a party, although not as legal counsel, or appearing as an expert witness or assisting the court in its decision making. The expert may even be a judge and involved directly in decision-making. These are the various types of experts which are discussed further below.

C.  Typology

Experts may be classified by the role they play in the dispute settlement process. This depends to a great extent on the appointing entity. Thus, the court-appointed expert plays a different role from one that is appointed by a party. An expert that is part of the tribunal, known as the expert judge, is still different from an expert that is party- or court- appointed. Nevertheless, experts may be further categorized into sub-types, and their roles may thus vary even if appointed by the same entity. Thus party-appointed experts may act as counsel or alternatively as expert witness. These various kinds of experts are described briefly in this section before further elaboration in the next section based on existing legal rules and practice.

The Rules on the Taking of Evidence in International Arbitration of the International Bar Association (Rules on the Taking of Evidence in International Arbitration (2010): International Bar Association (IBA)) is the only legal text to provide definitions of ‘party-appointed expert’ and ‘tribunal-appointed expert’, albeit in a rudimentary form. ‘Party-appointed expert’ means a person or organization appointed by a party in order to report on specific issues determined by the party; ‘Tribunal-appointed expert’ means a person or organization appointed by the arbitral tribunal in order to report to it on specific issues determined by the arbitral tribunal.

10  Classification of experts by subject-matter is not useful since theoretically there may be an expert on every conceivable topic, as evident from a study of experts in the dispute settlement system of the World Trade Organization (‘WTO’) (Experts: Dispute Settlement System of the World Trade Organization (WTO)). Legal experts are also sometimes involved in disputes, but not as legal counsel or judges. They are experts in law, be it domestic or international, and their role is akin to that of experts on other technical subjects and unlike that of other actors in the judicial process who have specialized legal knowledge (ie judges or advocates). This kind of expert is more often seen in investment arbitration (see Experts: Investment Arbitration).

11  Experts are commonly appointed by parties but the role they play differentiates between the expert acting as counsel and the expert witness. Party delegations in disputes before various international courts and tribunals often include ‘scientific and technical advisors’, some of whom even address the court as advocates would (Pulp Mills on the River Uruguay, Argentina v Uruguay, 2010; United States – Subsidies on Upland Cotton, Panel Report, 2004). However, it is important not to focus on the nomenclature of these individuals as they may be labelled in various ways in various fora and sometimes differently even before the same court or tribunal. The defining characteristic of this kind of expert is the advisory capacity in which they appear with the advice being provided to the party rather than the adjudicator.

12  At times, an individual referred to as ‘advisor’ may perform the role of expert witness (Continental Shelf, Libya/Malta, 1985, 14–15; Continental Shelf, Libya/Malta, 1984, 199–282). This means, that unlike the first kind of party’s expert, this individual would testify before the judges and the parties and could be subject to questions from the judges or the opposing party in cross-examination. Involvement in this procedure renders them akin to witnesses and distinguishes them from the advisors who act as counsel.

13  Experts that are appointed by the court or tribunal are generally appointed because the adjudicator felt the need for expert consultation on specific issues in dispute, irrespective of whether the parties had also appointed their own experts of either kind in the same dispute. Although international tribunals have the power to appoint their own experts, not all tribunals equally use this opportunity. Thus, while we see the frequent use of panel-appointed experts in WTO adjudication, that is not the case for experts in ICJ adjudication (Experts: International Court of Justice (ICJ)) and even less so for experts in ITLOS adjudication (Experts: International Tribunal for the Law of the Sea (ITLOS)).

14  A discussion of the official court-appointed expert is incomplete without a reference to the phantom expert, the expert known to be consulted ‘behind-the-scenes’ by adjudicators. Developed entirely through practice, while the phantom experts serve the same purpose as the official court-appointed experts, the difference lies in the absence of a legal framework governing the use of these internal experts. This unregulated expert consultation has led to some criticisms in terms of violation of due process requirements and the absence of transparency. Exceptions are however envisaged when seeking technical input on minor matters or practical implementation of the decision such as demarcation of a boundary. Experts assisting in boundary demarcation are however not necessarily undisclosed, especially when such appointment was requested by the parties (Frontier Dispute, Burkina Faso/Niger, 2013, 226).

15  An entity related to the court-appointed expert should also be briefly mentioned: the assessor in ICJ proceedings (Assessor: International Court of Justice (ICJ)). While not a kind of expert, it is worth referring to in the context of experts due to its nature, which is very similar to a court-appointed expert. Explicitly referred to as assessor only in the Statute and Rules of the ICJ (Art 30 ICJ Statute; Art 9 ICJ Rules), an identical entity is also envisaged under the United Nations Convention on the Law of the Sea (‘UNCLOS’) (Art 289 UNCLOS), though referred to as an expert. The distinguishing features of an assessor are that they sit with the judges and take part in deliberations, though without the right to vote. Moreover, the ICJ has the power to appoint assessors of its own accord, without prior ascertainment of the views of the parties (Thirlway, 2006, para 41). The experts envisaged under Article 289 UNCLOS have almost the same features and thus may be considered de facto assessors (Art 42 (2) ITLOS Rules). However, it is notable that these experts are selected in consultation with the parties. The UNCLOS drafting history reveals that a reference to the term ‘assessors’ was intentionally left out of Article 289, with the understanding that the ICJ would not be precluded from applying the provisions in its Statute concerning assessors in a manner compatible with Article 289 (UNCLOS Report, 1982, para 9(h); Rosenne, 1983, 32). Rosenne sees this provision as an important innovation through which ‘the concept of enlisting qualified scientific experts in a binding decision-making process has been introduced into modern international law’ (2007, at 245).

16  Apart from being appointed by disputing parties or by the court, expertise may infrequently also be built into the tribunal. The possibility of a tribunal having an expert judge depends on the requisite qualifications for the members of the tribunal. Where legal qualifications are not necessary, such as for WTO panels ( Panel: Dispute Settlement System of the World Trade Organization (WTO)), expertise may be incorporated into the tribunal. Special provisions for expert members may also be included, such as in the Indus Waters Treaty (1960), providing for the appointment of an engineer as one of the members of its Court of Arbitration (Annex G Indus Waters Treaty).

D.  Legal Framework, Rules, and Practices

17  The various means by which experts may be involved in a dispute cannot be fully understood without examining the rules and practices governing them in at least a few major international judicial fora. Though there are some common aspects, there is also a great deal of diversity in terms of the legal framework and even more so in terms of practice. This section examines the different ways in which an expert acts in an international dispute, with variations brought about by differences in rules governing them and the way that practices have developed in different fora.

18  All major international judicial bodies and treaties or rules otherwise providing for international dispute settlement refer to the possibility of using experts in one or more of the forms referred to in section C above. This section elaborates on the scope for involving such experts in the settlement of a dispute, relying partially on the written rules and partly on the practice that has developed around such experts.

19  The court’s or tribunal’s option to resort to expert advice is envisaged in almost all major international dispute settlement systems (Art 50 ICJ Statute; Art 289 UNCLOS; Art 82 ITLOS Rules; Art 13 WTO DSU; Art 11 (2) Agreement on Sanitary and Phytosanitary Measures (‘SPS Agreement’); Art 14.2 Agreement on Technical Barriers to Trade; Art 4.5 Agreement on Subsidies and Countervailing Measures; Art 25 Statute of the Court of Justice of the European Union (‘CJEU Statute’); Art 39 Additional Facility Arbitration Rules of the International Centre for Settlement of Investment Disputes, 2006 (Additional Facility Arbitration Rules (2006): International Centre for Settlement of Investment Disputes (ICSID)); Art 17 Arbitration Rules of the United Nations Commission on International Trade Law, 2013 (Arbitration Rules: United Nations Commission on International Trade Law (UNCITRAL)); Art 17 Arbitration Rules of the Permanent Court of Arbitration, 2012 (Arbitration Rules (2012): Permanent Court of Arbitration (PCA))). In the ICSID Arbitration Rules, the possibility of the tribunal appointing experts is foreseen only because it is not expressly prohibited by the rules, rather than any affirmative statement. This ambiguity is set to change, as understood from the updated Rules entering into force in July 2022 (ICSID, 2022, 44). As noted in its first working paper, this change is aimed at reflecting the reality of ICSID tribunals appointing their own experts for environmental assessment and other matters (ICSID, 2018, 204). Importantly, the SPS Agreement arguably imposes a duty on WTO panels to seek expert advice in disputes under the Agreement ‘involving scientific or technical issues’ (Art 11.2 WTO SPS Agreement), though some are of the opinion that this provision only encourages panels to do so (Baker and others, 2015, 281; Gruszczynski, 2014, 15).

20  In practice, one finds that for SPS Agreement disputes, WTO panels have consistently consulted scientific experts, individuals as well as specialized organizations. It is thus perhaps unsurprising that these panels have a more developed approach to appointing experts when compared to other judicial bodies such as the ICJ and ITLOS. The ICJ has overtly consulted experts on few occasions in its decades of existence—on a number of these occasions, for the assessment of compensation—and the ITLOS has never used the opportunity to do so. Apart from seeking the opinions of the disputing parties, WTO panels regularly consult with international organizations as a means of selecting experts with the desired qualifications. Even in the context of PCA arbitration, experts are appointed after consulting with the parties, and the appointed experts’ terms of reference are also communicated to the parties (Art 29 (1) PCA Arbitration Rules). Parties then also have the opportunity to challenge the expert’s appointment (Art 29 (2) PCA Arbitration Rules). By contrast, recent ICJ practice shows that the Court may decide to appoint experts even in the face of objections from one disputing party (Armed Activities on the Territory of the Congo, Democratic Republic of Congo v Uganda, 2020).

21  At the stage of consultation with experts, WTO panels seek inputs from the parties on the nature of questions to be asked of the panel-appointed experts. In some disputes, panels have had the opportunity to comment on or even suggest questions to be put to the expert. In contrast, after appointing experts under Article 50 ICJ Statute, the Court does not seem to involve the parties, at least to the extent at the WTO, in formulating the mandate of court-appointed experts. It is usual practice, though not mandatory or consistent, across tribunals to conduct a joint session with judges, parties, and the court’s experts to focus on the issues in their report, permit a thorough exchange of views, highlight important points, and clarify any points that are unclear or still at issue. While this has been followed over the years by WTO panels, it has not been as consistent at the ICJ. It is also not uncommon for site visits to form a part of the terms of reference of experts appointed by the Court, starting from 1948, until more recently in 2016 (Corfu Channel, United Kingdom v Albania, 1949, 9; Maritime Delimitation, Costa Rica v Nicaragua, 2016, 237).

22  All the above procedures are of course absent when one considers phantom experts. Since their consultation is not explicitly acknowledged in any given dispute, it is only through the writings of adjudicators (Pulp Mills on the River Uruguay, Argentina v Uruguay, Judgment (Joint Dissenting Opinion of Judges Al Khasawneh and Simma), 2010, 114), members of tribunal registries (Couvreur, 2004, 384), and scholars (Tams, 2012, 1298; Devaney, 2016, 84; Parlett, 2018, 445), that one is able to discern the extent and content of the practice. Acceptance of this arguably opaque practice varies across judicial fora and depending on the nature of expert advice sought. For example, with respect to ‘internal experts’ at the ICJ, despite harsh criticism from some members of the Court (Jennings, 1996, 416; Pulp Mills on the River Uruguay (Joint Dissenting Opinion of Judges Al Khasawneh and Simma), 114), others consider them to be neither experts nor phantoms but merely assistants to the registrar (Bennouna, 2018, 348). The approach to internal experts at the WTO is largely positive with panels regularly consulting economists from the Secretariat (Marceau and Hawkins, 2012, 504), though the same is not disclosed in panel reports. Panel-appointed economic experts are thus conspicuously absent from WTO jurisprudence. The in-house economists have been referred to as phantom experts (Valles, 2018, 377), though the assistance received from them has not been criticized.

23  The most common type of experts seen in practice are those used by parties in their delegations though their precise role may vary as described in section C above. Parties are considered to have the often implied freedom to present experts in furtherance of their arguments in almost every international dispute settlement forum (Arts 43 (5) and 51 ICJ Statute; Arts 58 (2) and 63 (1) ICJ Rules; Arts 72 and 78 ITLOS Rules; Arts 20 and 28 CJEU Statute; Rules 35 and 36 ICSID Arbitration Rules; Arts 41–43 ICSID Arbitration Additional Facility Rules; Arts 27–29 UNCITRAL Arbitration Rules; Arts 27–29 PCA Arbitration Rules). A notable exception is the WTO, where neither the DSU nor the other Covered Agreements indicate the parties’ right to call experts (Goldstein and Pereyra, 2018, para 4). This, however, does not serve as a legal impediment and does not indicate the absence of such an entity from WTO dispute settlement.

24  The nature of party-appointed experts envisaged in the above-mentioned provisions is that of an expert witness as evident from the reference to oral examination of these experts. The method of conducting oral testimony of experts acting as expert witnesses is similar across tribunals, whether the ICJ, ITLOS, or investment arbitration or other arbitral tribunals. The written submissions include a written report of the expert. The expert may nevertheless present their opinion orally as well. Sometimes this oral presentation, called the examination-in-chief, is dispensed with in favour of a written statement. This is followed by cross-examination by the opposing party, an option of re-examination by the appointing party, and questions from the judges. A time limit is usually decided by the judges in advance depending on the number of experts presented by each side and the number and complexity of the issues being addressed. One feature that stands out is the use of voir dire, seen most recently at the ITLOS (Southern Bluefin Tuna, New Zealand v Japan, Australia v Japan, 1999, 34). It is an effective procedural tool to test the qualifications or expertise as well as the independence of an opposing party’s expert called to testify in court. At the ICJ the former was tested (South West Africa, 1966, 341), while before the ITLOS it was the latter. This demonstrates that the procedure may be used for both purposes. It usually takes place before the examination-in-chief. As seen in the Southern Bluefin Tuna case (Southern Bluefin Tuna Cases), the procedure need not be ordered by the Tribunal. A less common practice, a meeting between experts of both sides could be used more frequently, to reduce areas of disagreement and aid in decision-making. This occurred early in the ICJ’s history in the Corfu Channel Case (Corfu Channel, United Kingdom v Albania, Pleadings 1948, Vol III, 616–17). In recent times, it has been popular as expert conferencing in mostly commercial international arbitration. It must be noted that in international arbitration, parties’ experts are more common than tribunal-appointed ones, and the former are involved usually as expert witnesses (Daly and Poon, 2014, 335).

25  Notwithstanding the exigencies of statutes and rules, practice has shown the frequent involvement of another kind of party’s expert termed as counsel or advisor. Such an expert is differentiated from the expert witness as a witness is distinguished from legal counsel. Expert counsel provide their written and oral statements much like an advocate would and they are not subject to cross-examination like a witness. The involvement of such experts was usual before the ICJ (Gabčíkovo-Nagymaros Project, Hungary/Slovakia, 1997) but the Court’s perspective on the use of experts as counsel rather than to testify as witnesses had evolved by the time it heard the Pulp Mills case in 2009 (Pulp Mills on the River Uruguay (Argentina v Uruguay)). The practice of experts acting as counsel was strongly criticized by the ICJ for the first time with the fault lying in the lack of opportunity to cross-examine the expert. Since then, the Court has seen a greater use of expert witnesses, however that has not been at the expense of expert counsel. In some cases, a party has included both kinds of experts in its delegation. In contrast to the practice before the ICJ, the ITLOS has seen greater use of expert witnesses by parties, rather than experts appearing as counsel. Indeed, parties have been quite liberal in their resort to expert witnesses in the few cases that have been decided by the ITLOS. However, as the ITLOS registrar notes, parties do not have complete freedom to call experts to testify on any matter. The Tribunal is entitled to decide on the relevance of any evidence which a party wishes to produce and to make a ruling on this matter (Gautier, 2018, 435). The use of party-appointed experts in WTO panel proceedings is significantly limited in comparison to other judicial fora. To the extent that they do appear, they are akin to counsel. There is thus no obligation on the appointing party to subject its expert to oral interaction. However, if the expert is in the delegation at a panel hearing and particularly if they are permitted to speak, that opens the door for the opposing party or the panel to pose questions to the delegation that are, in effect, directed at the expert (Philippines – Taxes on Distilled Spirits, Panel Reports, 2011, para 7.62). Other than this, there is a kind of cross-examination in the sense of ‘testing’ by the panel of the expert’s views (Valles, 2018, 375).

26  An expert’s ability to carry out their functions unhindered is enabled by provisions across fora, granting experts of all kinds privileges and immunities akin to those accorded to judges, arbitrators, counsel, and other participants in judicial proceedings (UN General Assembly Resolution 90 (1946); Art VIII Marrakesh Agreement, 1994; Arts 15 and 17 Agreement on the Privileges and Immunities of the International Tribunal for the Law of the Sea, 1997; Art 9 Agreement concerning the Headquarters of the Permanent Court of Arbitration, 1999; Arts 21 and 22 ICSID Convention, 1965).

27  Apart from the tribunal and parties appointing experts, an expert could be part of the tribunal. Unlike the way the above kinds of experts have developed through practice, often outside the bounds of treaty, statute, and rules, having an expert on the bench is critically dependent on legal textual backing. There is greater flexibility in arbitration that arises out of specific agreements to arbitrate which give much leeway to the parties to decide on the qualifications of their arbitrators. In certain jurisdictions, especially standing tribunals, such an option is excluded by specific qualifications required by the constitutive instrument. For example, judges appointed to the ICJ are required to have legal qualifications (Art 2 ICJ Statute). WTO panels are required to be composed of ‘well-qualified governmental and/or non-governmental individuals’ (Art 8.1 DSU). WTO panellists also need not be lawyers, or indeed, have a trade background at all. In one dispute, for example, a medical professional was appointed as a panel member (Canada – Pharmaceuticals, Note by Secretariat, 1999). Thus it is possible for experts to sit as judges in a WTO dispute. For UNCLOS Annex VII arbitration (Annex VII Arbitration: United Nations Convention on the Law of the Sea (UNCLOS)), arbitrators are only required to be persons ‘experienced in maritime affairs and enjoying the highest reputation for fairness, competence and integrity’ (Annex VII Art 2 UNCLOS). No legal qualification is mandatory. Moreover, under the specialized UNCLOS Annex VIII arbitration (Annex VIII Special Arbitration: United Nations Convention on the Law of the Sea (UNCLOS)), for specific kinds of disputes on technical fields such as fisheries or marine scientific research, arbitrators may be selected from a list of experts maintained for each of these fields. Their expertise is expected to be in ‘the legal, scientific or technical aspects’ of their respective field (Annex VIII Art 2 (3) UNCLOS), thus not requiring legal qualifications either. The Permanent Court of Arbitration also has specialized rules that can be applied in environmental disputes (Optional Rules for Arbitration of Disputes Relating to Natural Resources and/or the Environment: Permanent Court of Arbitration (PCA) (‘Environment Rules’)) and those that are applicable to outer space disputes (Optional Rules for Arbitration of Disputes Relating to Outer Space Activities: Permanent Court of Arbitration (PCA) (‘Outer Space Rules’)). These rules modify the UNCITRAL Rules to the extent that they can, inter alia, provide for establishment of a specialized list of arbitrators having expertise in the subject matter of the dispute at hand (Art 8 (3) Environment Rules; Art 10 (4) Outer Space Rules), and a list of scientific and technical experts (Art 27 (5) Environment Rules; Art 29 (7) Outer Space Rules). This list, however, does not bind the tribunal while selecting experts. Parties to a dispute are also free to choose arbitrators and expert witnesses from these lists, though they are not restricted to these lists. The general PCA Arbitration Rules do not set any restrictions on the qualifications of arbitrators either (Arts 7–16). This means that a non-legal expert could potentially be a part of the tribunal. An effective use of the expert judge was seen in the 2013 Indus Waters Kishenganga Arbitration (Pakistan v India), made possible by the unique multi-tier dispute resolution provisions of the Indus Waters Treaty. Chiefly negotiated by engineers from both sides, this agreement is also referred to as an ‘engineer’s Treaty’ (McCaffrey, 2019, 270). This is evident especially from the drafting of its dispute resolution provisions (Mbengue and Das, 2019, 8). The treaty envisages the appointment of a ‘highly qualified engineer’ to the tribunal, as one among seven arbitrators (para 4 (b) (ii) Annex G Indus Waters Treaty). The appointing entity was also predetermined in the treaty—the rector of the Imperial College of Science and Technology, London. This non-legal adjudicator played an important role in enhancing the tribunal’s competence in scientific fact-finding (Ma, 2017, 18; Crook, 2014, 314).

E.  Key Differences among Various Roles

28  In involving experts to aid in the resolution of an international dispute, the adjudicator is faced with expertise from myriad directions. Full control over appointment, expertise and other variables may be possible if court-appointed experts are used. The same is true for phantom experts, however without assurances of transparency or adherence to due process. On the other hand, if parties’ experts are involved in the proceedings, their utility also varies depending on their involvement as advisors/counsel or as expert witnesses. If the expert plays the role of counsel, their expertise is also treated more as arguments rather than as evidence (Pulp Mills; Forms of Evidence). Expert evidence is more likely to arise out of testimony from expert witnesses. If an expert is part of the tribunal, this may help in better assessing and understanding expert evidence coming from the parties, or even the expert opinions tendered by tribunal-appointed experts, if any. Such an expert member of the tribunal may facilitate other members’ understanding of the issues, undertake technical analysis, assist colleagues in weighing the credibility of scientific evidence and check facts and analysis (Keene, 2016, 255).

29  In-house expertise, often referred to as phantom experts, may determine whether a tribunal appoints experts through a transparent process. The WTO Secretariat has the responsibility of assisting panels and, among other things, providing technical support to them (Art 27.1 DSU; Secretariat: Panel of the World Trade Organization (WTO)). This provision, depending on the Secretariat’s in-house expertise on certain subjects, could affect a panel’s decision to appoint experts in a dispute. The same is true for other courts and tribunals where registries include cartographers, hydrographers, and such other technical experts. Without institutional backing, arbitral tribunals are more likely to overtly appoint experts when the issues at hand in the dispute demand it.

30  A cause for concern when involving any kind of expert, whether by a party or a tribunal, is the cost involved in retaining or appointing them. Whether states or private actors, parties have varying financial resources at their disposal to fund a litigation and this could often affect the decision to use experts in support of their arguments. Often, these costs can be transferred to the losing party if costs are awarded at the end of the dispute. However, along with the uncertainty of victory and costs in favour, it is still necessary to have funding until the end of the dispute. Funding is not necessarily easier when it comes to court-appointed experts. For example, the ICJ requested additional funds from the General Assembly when it decided to appoint experts and conduct site visits in the Maritime Delimitation case between Costa Rica and Nicaragua (Report of the International Court of Justice, 2016, para 39). Fees and associated costs are thus an important factor to bear in mind while considering the involvement of experts in a case.

31  The criteria for selecting experts would also be expected to differ based on their role as court-appointed or party-appointed expert. The role of an expert in their myriad characterizations has never been clear. It is debatable whether a court-appointed expert’s role is to review the expert evidence submitted by parties, or to conduct their own research or survey. Perhaps it can be both, depending on the requirements of the case. For example, in the South China Sea Arbitration (Philippines v China), the UNCLOS Annex VII tribunal was faced with numerous and varied expert reports from the applicant, the Philippines, while the respondent China chose not to appear. The tribunal thus appointed an expert hydrologist to help it in reviewing and analysing technical data, and because of China’s non-participation, to help with critical assessment of relevant expert advice and opinions submitted by the Philippines (South China Sea Arbitration, 2016, para 133). While the role of a court-appointed expert is less contentious, opinions are strongly divided when it comes to party-appointed experts—on whether the role of the expert witness is to help the party or the court. Preferences tend towards placing this expert in the court-assisting role (Keene, 2016, 254). This also makes practical sense, since otherwise a party’s expert becomes a de facto counsel and the exercise of submitting expert evidence is rendered futile.

32  Perhaps the most important component of making expert opinion useful in a dispute is by regulating the written and oral proceedings involving experts. The processes by which an expert’s opinion reaches the parties and is made accessible to the judge truly make it useful to the decision-making process. Several considerations are at play, in parallel, in the written and oral proceedings involving experts. Not only are these the stages when scientific opinions and studies are integrated into a legal dispute, with the objective of making complex technical evidence somewhat more intelligible to a lawyer, this also the time when an expert’s qualifications, expertise, independence, and impartiality can be tested.

33  The most important role for any kind of expert is to help the adjudicator with fact-finding, whether scientific, technical, or otherwise requiring specialized knowledge. All procedures governing experts involved in the judicial process should be formulated keeping in mind this paramount role.

F.  Conclusion and Evaluation

34  A defining characteristic of the procedural law of international courts and tribunals is its flexibility. This flexibility is largely due to the minimalist approach in the legal texts of these judicial fora. One of the consequences of this flexibility was the sparse involvement of experts in dispute resolution. This statement is not entirely accurate at present due to the noticeable rise in the use of experts in recent times. An increase in the use of experts in various capacities also leads naturally to the development and sometimes innovation of procedures involving them. Moreover, the more adjudicators are faced with scientific expert evidence, the greater judicial engagement with scientific evidence would likely lead to enhanced and improved techniques of assessing this evidence.

35  Expert involvement in any dispute is hardly effective without proper modes of appointment and effective written and oral procedures. With the goals of adherence to due process, transparency, and finally legitimacy of the decision, several considerations for expert appointment and procedures at written and oral stages should be indispensable. These include disclosures regarding relationships with the parties, right of the parties to comment on expert opinions, and party involvement in court procedures regarding experts. Different kinds of experts and different procedures may suit different disputes and this reflects the inherent flexibility of international dispute settlement.

36  With more frequent consultation of experts in international disputes and increased scholarly focus on the same, one may see the practice develop only further, directed towards tribunals learning from each other. Increased use of experts in their varied forms could lead to modification or refinement of the existing legal rules, as already seen in context of the ICSID. The expert is an important and complex actor in the sphere of international dispute settlement, one that adapts to the needs of the dispute but that also makes the system adapt to keep up with changing times.

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Cited Documents

Cited Cases