One Size does not Fit All—Uses of Experts before International Courts and Tribunals: An Insight into the Practice
BOISSON DE CHAZOURNES, Laurence, et al.
BOISSON DE CHAZOURNES, Laurence, et al . One Size does not Fit All—Uses of Experts before International Courts and Tribunals: An Insight into the Practice. Journal of International Dispute Settlement , 2018, vol. 9, no. 3, p. 477-505
DOI : 10.1093/jnlids/idy021
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One Size does not Fit All—Uses of Experts before International Courts and Tribunals:
An Insight into the Practice
Laurence Boisson de Chazournes*, Makane Moise Mbengue**, Rukmini Das*** and Guillaume Gros***
A B S T R A C T
This paper presents the results of empirical research conducted in context of a broader study on the use of experts in international disputes. An analysis of the inter- views conducted and responses received from questionnaires as part of this empirical research sheds light on various aspects of expert involvement in international dis- putes, revealing trends that are not discernible from a textual or casuistic approach.
The analysis in this paper also demonstrates interesting divergences as well as com- mon approaches to expert use in different international judicial fora, and among different actors in the judicial process - judges, counsel or experts themselves.
The paper concludes that no single uniﬁed regime can be identiﬁed for experts in international law, variances exist in connection with the forum considered. At the same time, the empirical study reveals universal characteristics in expert use mainly to be found in due process requirements.
1 . I N T R O D U C T I O N A N D R E S E A R C H M E T H O D O L O G Y
This contribution intends to present some of the results of a study directed towards experts in international dispute settlement, which comprised the sending of question- naires and involved conducting of interviews. This study constitutes the empirical as- pect of a broader research project on experts conducted at the Faculty of Law of the University of Geneva.1 The limited scholarship and study on the use of experts in international courts and tribunals prompted the initiation of this 4-year long project by the authors of this contribution. The objective of the research project is to gain extensive and detailed knowledge regarding the expert in international dispute
* University of Geneva. E-mail: email@example.com.
** University of Geneva and Sciences Po Paris (School of Law).
*** University of Geneva.
1 ‘Experts and International Courts and Tribunals’, funded by the Swiss National Science Foundation, Project number 10001A_156117, Swiss National Science Foundation, 2015–2019.
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settlement.2It intends to provide a comprehensive vision of experts in international disputes, and construct an overall ‘map’ of expert use in international law, in its texts and practices. Receiving and analysing the questionnaire responses was preceded by a phase of compilation and examination of the primary sources to identify a theoret- ical framework. This phase revealed a degree of similarity among the legal provisions surrounding experts before international courts and tribunals. These provisions are characterized by their broad scope and flexibility; they have therefore made space for a variety of practices to evolve over time. Consequently, difficulties experienced by judges, counsel or experts, when engaging with technical data in a legal dispute, are largely invisible to an observer outside the system. Critical to an in-depth under- standing of the subject was the supplementing of case analysis with the experience of key players in the field. On the one hand, the questionnaires were meant to enrich the understanding of the existing theoretical data, and on the other hand, provide certain considerations arising from the practice, which are not apparent from solely studying the texts. By way of example, the interviews were not designed to reveal the prevalence of the party’s expert over the expert appointed by the judge, but rather to inform the researchers about reasons driving the limited use of the latter. The par- ticular aims of the project prompted a specific research methodology.
The goal of the questionnaires and interviews was to understand the perception and appreciation of the expert in international dispute settlement by key players on the judicial scene. This goal was conducive to adopting a qualitative methodology for this part of the research. The qualitative empirical approach, not frequently employed in the international legal field, may be summarized as follows: “a
‘qualitative observation’ identifies the presence or absence of something, in contrast to ‘quantitative observation’, which involves measuring the degree to which some fea- ture is present.”3The investigation ‘attempt[ed] to capture and categorize social phe- nomena and their meanings’4and was not relying on quantitative measurement and statistics. This qualitative approach implied interviewing a limited number of people
‘in order to capture a spectrum of viewpoints and experiences . . .’,5an endeavour that would have been practically impossible were one to receive several hundred opinions. This is in opposition to a quantitative method which relies on the identifi- cation and ‘collection of large quantities of data from an entire population [. . .] in a systematic fashion’6so as to generalize the conclusions. As a consequence, with re- gard to data collection, the participants were selected following the ‘purposeful sampling’7 technique due to their specific and personal extensive experience and
2 The research design combines different studies and methods (theoretical and empirical). Currently, there exists no comprehensive study listing and analysing all the rules governing the use of experts before inter- national courts and tribunals, and drawing comparisons between these different rules, nor their eventual historic development.
3 J Kirk and ML Miller,Reliability and Validity in Qualitative Research(Beverly Hills Sage Publications 1986) 9.
5 L Webley, ‘Qualitative Approaches to Empirical Legal Research’ in Peter Cane and Herbert Kritzer (eds), Oxford Handbook of Empirical Legal Research(OUP 2010) 6.
7 Described by Patton as ‘The logic and power of purposeful sampling lie in selecting information-rich cases for study in depth. Information-rich cases are those from which one can learn a great deal about issues of
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knowledge of experts in international litigation. These individuals, at advanced stages of their careers and renowned in their respective fields, provided ‘rich sources of information’8justifying in-depth analysis of their responses, in opposition to an enu- meration and quantification of simple opinions.
It is rare to have a completely qualitative (or completely quantitative) research de- sign, and some limited quantitative elements have been used in the design of this re- search, by considering basic and logical considerations of representativity besides the personal importance of the individual. First, the categories of actors interviewed re- flect the different capacities of involvement in the judicial process: adjudicators, counsel, registry staff and experts. The identity of the consulted individuals has also been determined considering three other objective criteria: forum of involvement, legal tradition of origin and type of dispute involved in. An overall number of 61 responses were received and analysed. The fora considered were the International Court of Justice (ICJ), International Tribunal for the Law of the Sea (ITLOS), arbi- tral tribunals established under Annex VII of the UN Convention on the Law of the Sea, World Trade Organization (WTO) panels and Appellate Body, and arbitrations conducted under the auspices of the International Centre for the Settlement of Investment Disputes (ICSID), the Permanent Court of Arbitration (PCA) and other inter-State arbitrations. The questionnaires were not meant to lead to a precise statis- tical representation of opinions in the international legal community in a numerical way, but to allow the researchers to grasp the existing diversity of opinions and per- spectives.9 Due to the large number of questions and the sophistication in assess- ment of the responses along with the different perceptions of the legal institutions, a quantitative analysis in terms of statistics would make little sense, even if possible.
However, if the findings do not permit undue generalizations, or assessment, in a statistical manner, of the prevalence of one or another opinion or analysis presented, the relative importance of the sample allows identification of trends and common conceptions, or clear rejections.
Specific questionnaires were crafted for each category of individuals before each forum, according to the theoretical analysis conducted in advance and the legal speci- ficity of each forum. The number of questions ranged from 42 to 62, divided into three main sections intended to chronologically cover every aspect of each phase of expert involvement in judicial proceedings.10The interview responses, some written, and some recorded, have all been received under the Chatham House Rule, main- taining anonymity of the interview subjects. The data collected through these techni- ques required analysis and interpretation from the researchers, since it was not, as noted earlier, capable of a clearly measurable appraisal and representation. As no spe- cific hypothesis was tested, the research method employed is mainly inductive. The
central importance to the purpose of the inquiry, thus the term purposeful sampling. Studying information-rich cases yields insights and in-depth understanding rather than empirical generalizations’:
MQ Patton,Qualitative Research and Evaluation Methods(3rd edn, Sage 2002) 169.
8 ibid, see also on the topic, H Suri, ‘Purposeful Sampling in Qualitative Research Synthesis’ (2011) 11(2) Qual Res J 63.
9 ‘Will be representative in the sense of capturing the range of variation in a phenomenon, but not in the sense of allowing for the estimation of the distribution of the phenomenon in the population as a whole.’
10 Relations with experts before the oral proceedings, during and after.
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analysis of each set of questionnaire responses was completed individually, followed by all the responses of each category of actors for a specific forum.
This analysis has shown that there is a diversity of opinions on some fundamental questions regarding expert use. The diversity is not only of opinions but also of per- spectives. Thus, there appears to be great disagreement on certain aspects of the law and procedure, while certain key legal concepts relevant to experts have different meanings for different individuals involved in the same legal system. Disagreements range from the roles played by party-appointed or court-appointed experts, the use of invisible experts, and the merits of cross-examination, to the definitions of terms such as independence, impartiality and neutrality. Disagreements were also noted regarding the meanings of essential legal concepts like standard of review, admissibil- ity of expert evidence, scientific uncertainty and the nature of the judicial function.
The primary endeavour in analysing these interviews has been to reach a balance be- tween highlighting individual opinions and showcasing a combination of all opinions, thereby trying to reach the most objective result possible. The results of the analysis will thus be presented by forum. The project researchers will examine the responses from participants in the judicial process of the International Court of Justice (Section 2), the International Tribunal for the Law of the Sea (Section 3), those who participate in investment arbitration proceedings (Section 4) and WTO dispute settlement participants ( Section 5). The article concludes with lessons drawn from the above-mentioned survey, and avenues for further research and analysis that have been opened in light of this study (Section 6).
2 . I N T E R N A T I O N A L C O U R T O F J U S T I C E
This section provides an overview of some salient aspects of the insights gained from analysing the responses received from different categories of individuals involved with disputes before the International Court of Justice—some former and present judges of the Court and members of its registry (Section A), counsel who have appeared or ap- pear before the ICJ (Section B), and those who have appeared as experts, in different capacities, in disputes before the Court (Section C). A final part of this section brings together the various threads of opinion from these three categories, those in consensus and those in opposition, to provide a consolidated view of the ICJ (Section D).
A. ICJ Judges and Registry
An examination of the opinions of judges of the ICJ brought up varied responses and diverse perspectives. Legal cultural factors seem to play an important role in inform- ing the answers to many questions—resulting not only in differing opinions, but also, at times, different ways of comprehension of the same concept. However, several points of convergence can be identified in the opinions regarding expert use at the Court and on some occasions, unanimous views. Indeed, beyond the diversity, a com- mon approach can be seen with regard to definitions, presuppositions and overall as- sessment of certain issues (though the justification may differ). The approach is also unified by its marked difference from that of the counsel and expert responses.
Judges, both present and former, betray, in general, what could be termed a trad- itional or conservative approach from their responses. They prefer the status quo,
stressing a wide scope for interpreting the Statute of the Court and its Rules.
According to them, therefore, the present legal framework for experts seems to work well, and there is no need for change in that respect. However, paradoxically, their responses also reveal a preference for more precision in the Rules, for the purposes of handling expert evidence, implying clearer guidance to both the Court and the parties. The traditional approach is also reflected in the fact that most respondents are unacquainted with new techniques and procedures of dealing with experts11and perhaps because of this unfamiliarity, are also unenthusiastic about incorporating them into the oral proceedings.
Responses also reveal the limited consideration given to the definition of the role of experts (and consequent duties and attributes), whether appointed by a party or the Court.12 While dwelling on these questions, responses are a mixed bag of pre- scriptive and descriptive, making it difficult to find a clear trend on the existing role, and the ideal role that each category of expert should perform. Broadly, respondents note that the role of the party-appointed expert includes a presentation of the facts, a personal assessment of these facts and a pervasive requirement of the quality of hon- esty or fairness (without reference to independence or impartiality). A Court- appointed expert’s role is the same according to some, except for a greater need for objectivity. According to others, this expert has a role different from that of a party’s expert, because of the absence of cross-examination.
Even when absent in the respondents’ definition of the role of experts, the requirements of independence and impartiality are often considered critical to, among other things, assessing expert evidence. However, the discussion on these eth- ical requirements reveals that not much thought has been given to defining the terms, nor have procedures been developed or even considered for determining their existence. It appears that ‘no real difference’ is made between the concepts of inde- pendence and impartiality, the two terms being used most often interchangeably.
Those who attempt to define independence, do so in terms of ‘lack of connections with the party’ or ‘not acting as a form of counsel when they testify’. A respondent also believes that these requirements are only applicable in case of court-appointed experts and do not apply to party-appointed experts.
In contrast with existing practice,13all judges interviewed considered the possibil- ity of using such experts, while some even actively supported greater use ofex-curia
11 The interviews included questions on expert conferencing, hot-tubbing, expert teaming and single joint expert. For a discussion on these procedures, see MJ Hunter, ‘Expert Conferencing and New Methods’ in A J van den Berg (ed),International Arbitration 2006: Back to Basics?(Kluwer Law International 2007) vol 13.
12 Questions on this aspect were included in all questionnaires in the survey due to the absence of a unified understanding of the role of different kinds of experts, be they court-appointed, counsel-experts, expert witnesses or appearing in any other capacity.
13 M Moı¨se Mbengue, ‘Scientific Fact-Finding by International Courts and Tribunals’ 3 (2012) JIDS 509; D Peat, ‘The Use of Court-Appointed Experts By the International Court of Justice’ (2014) 84 BYBIL 271, 276; A Riddell, ‘Evidence, Fact-Finding, and Experts’ in CPR Romano, KJ Alter and Y Shany (eds),The Oxford Handbook of International Adjudication(OUP 2014); L Malintoppi, ‘Fact Finding and Evidence before the International Court of Justice (Notably in Scientific-Related Disputes)’ 7 (2016) JIDS 421, 435.
experts. In this context, theCorfu Channelcase,14the first decided case by the ICJ, and the last that saw the Court appointing experts of its own accord15until 2016,16 was cited with approval as an example to follow. At the same time, there is a preva- lent fear of delegation of the judicial duty to court-appointed experts, a possibility that could arise if the expert receives too wide a mandate in terms of fact-finding or assessment of scientific evidence or if her opinion is incorporated into the decision without application of the legal mind.
Thus, in attempts to gain a clear picture on an aggregated analysis of the responses, questions such as the duty of the party’s expert (to the party or the Court), the inde- pendence requirement of a party’s expert (whether the same as that of the Court- appointed expert) and the task of an ex-curia expert (whether to review party evi- dence or provide new evidence), remain to be clarified. This lack of precision and divergences regarding such questions is intriguing, since these definitions form part of the expert regime and could affect questions of evidence such as admissibility.
A particular perspective onexperts fantoˆmes17emerges from the responses. While largely emphasizing that the use of Court-appointed experts needs to be transparent, the respondents specify a certain kind of expert that the Court appoints. According to them, those that assist the Court with ‘technical details’ such as drawing a land or maritime boundary, ‘their expertise plays no role in the determination of the dispute’.
Thus, the need for transparency in appointment and other processes need not apply to them.
B. ICJ Counsel
It is clearly discernible in the responses received that almost every person inter- viewed in this category, as opposed to the judges, adopted very distinctive and identi- fiable approaches towards issues of expert use, that seem to reflect their professional backgrounds. This highlights the relevance of cultural factors in our analysis as also emphasized by one of the respondents. There is a diversity of opinions on certain fundamental questions and even disagreement on the meaning of important terms.
This diversity is in itself enlightening, revealing the absence of a clear and established framework for the use of experts, leaving substantial leeway for personal understand- ing, informed by personal experience and interpretation.
Considering this diversity of views, the points of agreement are even easier to identify.
All respondents consider thatde factoorde jure, the party’s expert behaves as an advisor for the party. Indeed, some respondents point out that they often collaborate
14 Corfu Channel Case(United Kingdom v Albania) (Merits, Judgment)  ICJ Rep 4.
15 In theGulf of Mainecase, the Court appointed an expert at the request of parties, provided in thecompro- mis:Delimitation of the Maritime Boundary in the Gulf of Maine Area (Canada v US)(Merits)  ICJ Rep 246, 253 (art II.3 of thecompromis).
16 Maritime Delimitation in the Caribbean Sea and the Pacific Ocean (Costa Rica v Nicaragua),Order of 31 May 2016  ICJ Rep 235.
17 or ‘phantom experts’. The term appears to have been coined by Judges Al-Khasawneh and Simma in a joint dissenting opinion:Pulp Mills on the River Uruguay (Argentina v Uruguay)(Judgment) (Joint Dis Op Al- Khasawneh and Simma),  ICJ Rep 108, 114; see also P Couvreur, ‘Le Re`glement Juridictionnnel’ in Socie´te´ Franc¸aise Pour le Droit International (ed),Le Processus du De´limitation Maritime : Etude d’un cas Fictif—Colloque International Du Monaco du 27 au 29 Mars 2003(Pedone, Paris 2004) 349.
with experts in framing their arguments. They are generally in agreement on the dis- tinct roles of Court-appointed and party-appointed experts, only the former being appointed to assist the Court. Interestingly, respondents emphasize the duty of hon- esty for party-appointed experts, while at the same time requiring this expert to sup- port the party’s position. There is moreover a quiet acknowledgement that the knowledge brought by the party-appointed expert could be biased, precisely by the fact of being appointed by one party. Numerous respondents suggest cross- examination as the most efficient and definitive solution to this problem of bias.
Impartiality is almost not considered by the respondents, and the definition of inde- pendence does not get much attention either, except in reference to a party- appointed expert’s role—‘to offer ‘independent’ expertise that supports the party’.
Most respondents also do not see a difference between these two concepts, akin to the judges.
As noted above, cross-examination is highly recommended to identify potential expert biases and more generally to assess the ‘integrity of expert evidence’. It is also preferred over the new methods of oral interaction such as the ‘expert teaming method’. Opinions are divided on the development of rules or guidelines for greater precision in this procedure, though a majority is satisfied with the status quo. The relative legal uncertainty for the parties resulting from the absence of guidance regarding this aspect of the oral proceedings is somehow perceived as unproblematic by most of the respondents. The authors note that some procedural decisions in the past have been made ‘on the spot’ by the President of the Court18seemingly relying on some unspoken rules, in accordance with the wide-ranging guiding principles of oral procedure in common law.19
All counsel interviewed agree with the suggested reduction in quantity of scientific/technical evidence submitted to the judge. Moreover, they all consider it advisable or a least possible, to receive more guidance from the bench, as to the expected content of expert reports.
Finally, in contrast with the judges interviewed, respondents in this category are unanimous on the dubious nature of the practice of using phantom experts. In this sense, according to the counsel, the requirement of transparency clearly appears to be the common thread and one of the more important characteristics of the expert process.
C. ICJ Experts
The respondents in this category bring with them varied experiences, be it in their capacity of intervention (as counsel or expert witness) or their field of expertise.
Despite this diversity of involvement and backgrounds, experts display more unified perspectives and opinions than the lawyers consulted.
18 See, eg,Elettronica Sicula S.p.A. (ELSI) (USA v Italy), (Judgment)  ICJ Rep 15;Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v Serbia and Montenegro), (Judgment)  ICJ Rep 43;Certain Activities Carried Out by Nicaragua in the Border Area (Costa Rica v Nicaragua) and Construction of a Road in Costa Rica along the San Juan River (Nicaragua v Costa Rica), (Judgment)  ICJ Rep 665.
19 HM Malek and others (eds),Phipson on Evidence(17th edn, Sweet and Maxwell 2010) 354, paras 12–11, 12–15.
Experts are quite clear and in agreement regarding the definition of their role in the procedure when appointed by a party. This role is to enlighten the judge, on the party’s behalf, on technical issues within their areas of expertise, using words and in a manner intelligible to a lawyer. This is opposed to the opinions of the judges and counsel interviewed, who envisage this expert’s role as supporting the party. They emphasize that maintaining ‘professional independence’, ‘professional integrity’ and honesty is inherently important to them, and not merely because the weight of evi- dence provided by an expert deemed to be partial would be diminished.
Related to issues of independence and impartiality, experts find a difference be- tween ‘advocating’ and ‘expounding on the correct understanding of’ science, favour- able to the appointing party. This is significant for understanding what
‘independence’ means for experts. To elaborate, as long as the experts are stating what they believe to be true and are not being dishonest to support the party appointing them, they consider themselves independent. In their opinion, even selecting, in favour of the appointing party, among more than one justifiable scientif- ic opinion, an expert remains independent, if the opinion expressed is scientifically reliable. The experts interviewed do not consider that this selection affects the impar- tiality of an expert either (this word seems to be used as a synonym for independ- ence). Independence is maintained even if the expert meets with the legal team, as long as it is to discuss specific scientific issues, and the expert does not know the legal strategy until the oral hearings. However, respondents also mention that parties made them understand the legal issues involved, and the legal significance of tech- nical terms in dispute. Another respondent speaks of frequent collaboration with the party’s legal team. The absence of personal link between the expert and appointing party is not considered relevant for establishing independence. The use of ‘independ- ence’, ‘impartiality’ and ‘honesty’ interchangeably by the authors in this paragraph reflects the frequent substitutions that the respondents made, among these terms, leading to difficulty in understanding what is precisely meant by each of them.
As the interview respondents explain, experts that appear as witnesses are trained by the legal team for cross-examination.20 Respondents are all in favour of cross- examination remaining an integral aspect of expert procedures, since it helps in exposing the real issues in dispute. However, this is not to say that cross-examination is a straight path to easy resolution of scientific issues. Since opposing parties may produce experts to give opinions on different issues, without any guidance from the Court as to the area of expertise or issues to cover, the judges may ultimately be pro- vided with one-sided data or evidence on several issues. The responding experts do not believe that the judges alone can assess conflicting scientific evidence to adjudi- cate on scientific issues. At the same time, absent clear definitions of independence, impartiality, there does not seem to be any clear parameters for judging the credibil- ity, expertise or competence of an expert appearing before the Court.
The respondents strongly favour appointment of an expert by the Court, if only as a ‘third voice’, to review the work of party-appointed experts. This preference
20 This could raise the fear of a lack of independence and conflation with the role of counsel; however, it must be kept in mind that even fact witnesses, whose role is never confused with that of counsel, are trained for cross-examination.
derives,inter alia, from the absence of clarity and technical errors21in past decisions of the Court. The prevalent opinion is that the Court cannot, by itself, properly understand and assess the quality and veracity of technical evidence provided by the parties. The ‘third voice’ would therefore assist the Court in understanding, assessing and clarifying the complicated aspects of this evidence, review the draft judgment.
They should not conduct their own research, and not decide on behalf of the Court.
However, it should be noted that even though theex-curiaexpert isde jure strictly neutral, she would also inadvertently bring to bear her own background and prejudi- ces into her assessment and may never be truly impartial—this is common with the views of the counsel interviewed, as well as some judges.
To different extents, collaboration between opposing parties’ experts is favoured, since they help in narrowing the points of disagreement, which is helpful for the judges. The prevailing opinion is also in favour of new techniques and procedures22 developed in other spheres of international dispute settlement, not yet used by the ICJ, which also have the same effect of narrowing down the issues in dispute.
D. Combined Outlook on ICJ responses
The first conclusion from the overall responses related to the ICJ would be the pos- sible utility of establishing a common theoretical framework of the expert before the Court. Indeed, the respondents display a great variety of opinions, exhibit profound disagreements and above all, adopt different perspectives and grids of analysis.
However, they also share common concerns and there is agreement on certain points, among all respondents (Section i). On this basis, it is also possible to identify differences among the three categories of respondents, displaying divergences in opinion that may reflect the roles they play in the judicial system (Section ii).
(i) Shared concerns and agreement on aspects of the use of experts among all respondents
From an aggregation of the answers, beyond the disagreements there emerge common features in the answers as well as a certain pattern of understanding on several aspects:
such as the ethical obligations of experts, the potential use for a ‘third voice’, concern regarding the delegation of the judicial function, the utility of collaboration between parties’ experts and need for the reduction in quantity of expert evidence submitted.
The first common feature is the lack of clear definition of terms such as independ- ence and impartiality, and the lack of clear conception of the role played by the dif- ferent kinds of experts. Along with ‘independence’, the respondents often use terms like ‘neutrality’ and ‘honesty’, while impartiality is hardly, if ever, brought up. The axiological dimension of these terms fits the rather undetermined definition of the expert’s role. Moreover, the ambiguity in expected qualities of an expert arguably ul- timately undermines the value of the expert opinion.
That being said, assuring the effective independence of the expert was revealed by consensus to be a concern. Some respondents consider feasible the disclosure of the
21 SeeLand and Maritime Boundary between Cameroon and Nigeria (Cameroon v Nigeria: Equatorial Guinea intervening), (Judgment)  ICJ Rep 303.
22 Above (n 14).
expert’s terms of reference and contacts with counsel of the parties, to allay doubts regarding his independence. Practice is varied, but in some cases the expert meets with the team, assisting it in framing the arguments in the case. The authors thus inferred that this assistance does not imply the betrayal of the expert’s convictions or his/her scientific standards. As the experts’ responses reveal, the expert often presents the various possible options to a problem, and in cooperation with the party, then supports the option most favourable to the party. Interestingly, this is not perceived to demonstrate a lack of independence or even partiality.
The responses also reveal common concerns regarding the involvement of theex- curia expert in the judicial process. The fear of delegation of a part of the judicial function is expressed, as well as apprehensions regarding the absence of an adversar- ial aspect in the process. Questions also arise regarding the burden of proof and equality between the parties. The judge, by appointing an expert, would somehow interfere with the normal allocation of the burden of proof andde factofavour the party invoking the fact in issue. These concerns seem to point towards the reasons for limited use of theex-curiaexpert in practice.
While reservations were expressed regarding ex-curiaexperts, the utility of a ‘third voice’ arose from the responses, to decide between competing scientific arguments. All kinds of interviewees contemplate this possibility to different extents. The experts consid- ered it more of a necessity, all expressing concern as to the capacity of the judge, trained in the law, to effectively assess the different expert reports and presentations resulting from cross-examination. It is a common opinion that in some cases the adjudicator could need some additional information to properly assess and weigh the expert evidence. In that respect theKishenganga23case has been cited as example, illustrating the opportun- ity for lawyers to rely on the advice of scientists to correctly understand expert evidence.
Respondents also agreed on the importance of reducing the quantity of expert evidence. This could be achieved by the judge using his capacity to provide guidance as to the content of the experts’ reports, both with respect to the substantive issues addressed and the form of the report.
Respondents welcome collaboration between experts to ease the judge’s work- load. The means that they consider, tend towards the following objectives: identifica- tion of methods, comparison, and identification of the points of agreement and disagreement. Different techniques can be used to achieve this goal, before and dur- ing oral proceedings: such as pre-hearing conferences and joint reports. Unfamiliarity with these procedures is perceptible in the responses, though the degree of acquaint- ance may vary among the individuals. However, even when associated with some practical difficulties, the idea of exchanges between the experts before the oral pro- ceedings is considered valuable. Added to that, from a more theoretical perspective, this method is in line with the understanding that the role of the experts, even if pre- sented by parties with opposing positions and arguments, is to help the judge by exhibiting their specialized knowledge.
23 Indus Waters Kishenganga Arbitration(Pakistan v India) (Final Award), 20 December 2013,<pcacases.
com/web/sendAttach/48> accessed 7 February 2018. This case included on its 7-judge bench, Dr Howard S Wheater, FREng, an engineer, along with six other judges, trained in the law.
(ii) Opposing views among categories of respondents
A marked diversity of opinions could be found among judges, counsels and experts on the efficacy of cross-examination, on phantom experts and the importance of transparency in that context.
As asserted by most judges and counsel interviewed, cross-examination is the best means possible to arrive at an approximation of the ‘truth’. This technique, according to the responses, would allow judges to overcome every kind of bias (conscious or unconscious) or inaccuracy affecting expert evidence. It is the best means of reveal- ing the inherent scientific quality of the expert’s opinion and independence at the same time. The trust in this technique is such that it can supplant the different safe- guards and legal techniques that have been implemented in common law countries24 but are absent in the Court’s judicial practice. The responses from the experts, how- ever, reveal a concern about the capacity (or incapacity) of an assembly of lawyers to effectively understand, in a scientifically sound way, the relevance and merit of a sci- entific approach, even if obtained after cross-examination. Several examples illus- trated errors in past decisions, resulting from an inadequate assessment of the expert evidence.25 Thus although the experts agree on that cross-examination is essential, they do not perceive it as a sufficient procedure to efficiently make use of expert knowledge in a scientific dispute.
Even if there is no direct opposition of views on transparency, counsel and experts place special emphasis on this procedural requirement. The responses of the judges do not reflect the same concern. Equal treatment of the parties is the component of transparency that seems to be the major concern. Counsel and experts repeatedly and clearly emphasize as being of utmost importance, the translation of this ideal into practice. They consider it necessary for the legitimacy of the decision to make the judicial reasoning clearly visible in the judgment. A related issue concerns the use of experts by the Court without the knowledge of parties (phantom experts). As mentioned earlier, experts and counsel have unequivocally manifested their disap- proval of this practice, whatever the nature of the involvement of this ‘unseen’ expert.
According to them, no exception to this should be permitted. Judges do not support this practice either, but with some important exceptions as discussed in Section II(A). Permitting such an individual to provide an unchallenged opinion to the Court, according to some respondents, could violate requirements of transparency and due process, as well as affect implementation of the decision.
3 . I N T E R N A T I O N A L T R I B U N A L F O R T H E L A W O F T H E S E A This section delves into the insights gained from an analysis of the responses received from the various individuals involved with disputes before the International Tribunal for the Law of the Sea—some former and present judges of the Tribunal and its registry (Section A), counsel who have appeared or appear before the ITLOS
24 Such as pre-hearing conferences, expert conferencing and hot-tubbing. See UK Civil Procedure Rules (1998), Rule 35.12; Expert Evidence Practice Note (GPN-EXPT), Federal Court of Australia<www.fed court.gov.au/law-and-practice/practice-documents/practice-notes/gpn-expt>accessed 7 February 2018;
US Federal Rules of Civil Procedure, Rules 16, 26.
25 See, eg,Cameroon v Nigeria(n 21).
(Section B), and only one expert that the research team was able to interview from this forum (Section C).
A. ITLOS Judges and Registry
Some varied responses are to be found from these respondents, and clear profiles ap- pear throughout the answers. Different answers were provided concerning important theoretical concepts (role of the expert, role of the judge, capacity of dealing with sci- entific evidence) but these discrepancies, interestingly enough, do not produce any noticeable shifts regarding practical answers. None of the respondents advocate changes in the system. No clear reform has been suggested as to the text or to the practice, even by one respondent who at the outset in his responses states that the Tribunal is not well-equipped to deal with scientific issues.
These respondents display a general satisfaction as to the functioning of the sys- tem and do not identify any evident problem that needs to be addressed. Some im- portant points in common can be identified with the responses from the ICJ.26 An appreciable number of conclusions arising from the analysis of these interviews are in fact identical to the ones from the ICJ.
First, all the respondents seem to share the assumption that the party-appointed expert is to be considered the norm for assessing scientific or technical issues, since it is self-sufficient and demonstrably efficient.Ex-curiaexperts may be used, in add- ition to the aforementioned, under certain circumstances. It has been considered, at best, as a theoretical possibility.
As to the role of the expert, the answers are characterized by their lack of clarity (with the notable exception of one respondent) and their disregard for the concept of impartiality. One respondent makes clear, at least in his first answer, that an expert should have the same role, irrespective of the appointing entity. His comment is at a theoretical level. The remaining respondents used exactly the same reasoning as found with the ICJ respondents, considering the expert as an advisor of the appoint- ing party even though constrained by the ethical and other obligations imposed on every scientist with professional integrity. As with the ICJ questionnaire, the parallel with the functions of an advocate is striking. According to the responses, like an ad- vocate, the expert has to make the case for the appointing party but within the bounds of professional rules. The respondents consider the expert a part of the legal team and participating as a counsel before the Tribunal as a legitimate and valid pos- sibility. This is why the wording to be found in answers of both ICJ and ITLOS responses is identical: ‘honesty’ and ‘scientific integrity.’ These terms are broad enough to encompass the attributes necessary to achieve a seemingly impossible bal- ance between independence and deliberate support.
As a result, only one respondent contemplates the possibility of implementing a code of conduct. Regarding the means at the Tribunal’s disposal to assess this elusive independence, he is the only one to mention the ‘voir dire’ process. This is a process used for testing the independence of an expert witness in US courts, unusual for an
26 On the common aspects and differences between the legal framework and practices of the two fora, see L Boisson de Chazournes and G Gros, ‘L’expert et le Tribunal international du droit de la mer’ inLes 20 ans du Tribunal international du droit de la mer(Pe´done 2017) 185.
international tribunal.27Used before the examination of a witness begins, for testing his/her eligibility, this process is distinct from cross-examination. Thus, the party conducting thevoir direis not permitted to question the witness on the subject mat- ter of the issues involved. In the single ITLOS case where this was used, the President of ITLOS, drawing a distinction between the expert’s independence and thus suitability as a witness, and his capacity and expertise, clarified that the question of whether the expert is capable of providing scientific evidence, is part of the evi- dence itself, and not a component ofvoir dire.28It is not surprising that only one re- spondent mentioned this procedure, since it has so far been used only once at ITLOS, even when an occasion later arose in the Malaysia v Singapore dispute29 where the impartiality of a testifying expert was clearly in question.
The other interview respondents rely completely and solely on cross-examination to reveal any kind of bias (and scientific inaccuracy) that could affect the expert testi- mony. It is a unanimous opinion that cross-examination is of paramount importance and efficiency.
When asked about the role of theex-curiaexpert, respondents discuss the support provided to the judge in assessing the expert evidence submitted by the parties. Yet, one respondent develops on the necessity to educate the parties as to the role of the ex-curiaexpert, which does not involveper seany delegation of the judicial function.
The respondents are divided regarding the utility of techniques that would foster collaboration between party-appointed experts. Differing from the judges of the ICJ, some respondents from the ITLOS are open to the possibility of using techniques such as expert conferencing or pre-hearing conferences, with the agreement of par- ties. It is also noted that the ITLOS Rules provide sufficient flexibility ‘for developing guidelines in this field’.
The use of experts by the Tribunal results from the particular way it handles sci- ence. The regime of the expert before ITLOS can hardly be understood in isolation from the broader issue of the status of science in the law of the sea (as conceived by the Tribunal). As one respondent states: ‘in light of ITLOS approach ‘scientific uncertainty’ consists in conflict[ing] scientific evidence b[y] equally reliable scientific experts.” In this type of case, the judges will then draw inferences from this uncer- tainty and will not have to adjudicate between two competing scientific arguments presented by the party-appointed experts. That is another conceivable reason why the Tribunal did not find it necessary so far to appoint its own experts or make use of assessors as provided by Article 289 of UNCLOS. The Tribunal, confronted with scientific uncertainty, relies on a ‘precautionary reasoning’, that has direct influence on the integration of scientific evidence in the judgment and on the type of expert
27 It was used only once at the ITLOS, in theSouthern Bluefin Tunacases between Australia and Japan:
Public sitting held on Wednesday, 18 August 1999, at 10.00 a.m., at the International Tribunal for the Law of the Sea, Hamburg, President Thomas A Mensah presiding in theSouthern Bluefin Tuna Cases (New Zealand v Japan; Australia v Japan) (Requests for Provisional Measures), Verbatim Record, ITLOS/PV.99/20/Rev.2, 34.
28 ibid 38.
29 Land Reclamation by Singapore in and around the Straits of Johor (Malaysia v Singapore), Provisional Measures, Order of 8 October 2003,  ITLOS Reports 10.
evidence required. These approaches make it all the more difficult to grasp the expert regime before ITLOS, because it is directly linked to the substantive legal issues.
The examination of the responses also indicates the existence of phantom experts at the Tribunal. The respondents mention a category of experts which may coincide with the definition of phantom expert. While the Tribunal never made use of the possibility provided by Article 289 to appoint ‘expert-assessors’, it is interesting to note that some experts, according to all respondents, are working with the registry (not officially appointed). They help the registry in assessing scientific evidence and help in redacting the judgment [sic]. We could wonder why in these circumstances (where there is an apparent necessity of external technical help), the Tribunal disre- gards Article 289 of UNCLOS. One response suggests that it is the excessive proxim- ity (in status and qualification) between these experts and the judges, which somehow makes them refrain from soliciting the support of these individuals. The presence of unofficially appointed experts and the non-use of article 289 remains nevertheless intriguing.
On the question of appointing an expert after the completion of the written and oral proceedings, one respondent shelters behind his duty of confidentiality. Others confirm this possible use of the registry. This practice raises questions both about the role of these experts and the role of the registry in that respect. While the issue of phantom experts has been discussed in the context of the ICJ registry,30the same concerns apply to the ITLOS. Albeit improving efficiency in clarifying issues of minor importance, it can be considered that this opaque process disregards the par- ties’ right to comment, an important facet of the sound administration of justice, which is thereby undermined.31
B. ITLOS Counsel
Responses from this category overlap to a great extent with those of the ICJ counsel, not least because the individuals themselves overlap to a great extent with counsel at the ICJ. Yet, it is useful to highlight some key opinions of these respondents.
Each of the individuals interviewed demonstrate varying approaches towards the use of experts. Like ICJ counsel, it was difficult to identify too many points of agree- ment, or even a few points of disagreement, to find the different threads of opinions on any aspect.
Akin to the judges of the ITLOS and the ICJ counterparts, these respondents too consider the role of the party’s expert to be that of an advisor or advocate, and there is a natural presumption that such an expert is biased. As one respondent puts it ra- ther paradoxically, the role is to “offer ‘independent’ expertise that supports that party”.
Notwithstanding the above example, if one were to examine all the responses of these counsel as a whole, ‘independence’ as a term is hardly used to describe experts, neither is ‘impartiality’. ‘Honesty’ is used more liberally, along with ‘credibility’. It is
30 Above (Section 2).
31 CJ Tams, ‘Article 50’ in A Zimmerman and others (eds),The Statute of the International Court of Justice: A Commentary(OUP 2012) 1287 at 1298; Markus Benzing, ‘Evidentiary Issues’ in Zimmerman ibid 1234 at 1259.
not possible to gain a precise understanding of these terms however, from the con- texts of the responses. Thus, eventually, we are left with an abstract understanding of the ethical obligations of experts.
Cross-examination is unanimously considered very important, in fact the most ef- ficient means of exposing weaknesses in the expert’s report and opinions. One re- spondent finds it a ‘better way to secure and test the integrity of expert evidence’
than drafting a code of conduct. Cross-examination is even preferred to the newer oral procedures such as expert conferencing, though that might be due to their lack of familiarity with these procedures, as revealed in the responses. When asked about the absence of a precise procedural framework governing cross-examination, some respondents are not in favour of more rules in this context, since it involves non-lawyers. A contrary opinion is that rules should be developed so that cross-examination is lessad hoc. There is also a minority opinion against the cross- examination of experts altogether. According to this interviewee, experts are usually well-prepared by counsel, thus nothing of significance is to be gleaned from ques- tioning them. In other words, their lack of independence and impartiality renders cross-examination futile.
Finally, the approach to phantom experts is also akin to that of ICJ counsel.
The lack of a well-defined approach towards expert evidence and the consequent freedom of the adjudicator is, in the words of one respondent, “especially problemat- ic if the Court relies on a ‘phantom’ expert unknown to the parties, whose views are not subject to scrutiny by them”. The primary concern expressed is that parties should be able to ‘raise issues concerning the skill and the independence of the expert appointed’. One respondent prefers that the tribunal, rather than the parties, appoint experts, but only if done ‘openly and transparently’.
C. ITLOS Expert
The sole expert interviewed with experience at the ITLOS, does not find much dif- ference between working with parties and judges. In an important respect, her answers are very similar to those of the other experts before other international courts or tribunals. She considers herself as part of the team, and for her, being appointed by a party entails supporting the party’s claim. Only a court-appointed ex- pert is expected to be independent. At the same time, the expert balances the duty towards the appointing party with honesty on technical matters. Similar to the ITLOS judges interviewed, the responses of this expert regarding her role support the belief that the expert is an advisor of the appointing party even though con- strained by the ethical and other obligations imposed on every scientist with profes- sional integrity. It is the role of a party-appointed expert to support the contentions of ‘his/her party’.
Like the other interviewed experts, she raises an important criticism of the effi- ciency of cross-examination, stating that this practice can lead to some misunder- standings and misleading simplifications. Along with her colleagues who appeared before the ICJ, she warmly welcomed any proposal for working in conjunction with the expert of the other party. Therefore, she is also open to participating in
pre-hearing conferences or expert conferencing, which she thought ‘has a number of benefits’.
This expert’s overall impression of the expert process at the ITLOS is that it worked well in her experience. She placed the greatest emphasis on the ‘credibility’
of the expert: ‘it is essential that any technical expert has a strong international pro- file and credibility’. The term ‘credibility’, however, remains undefined.
4 . I N V E S T M E N T A R B I T R A T I O N
The analysis of responses in this section is in two parts: the first, due to the special circumstances in investment arbitration is an analysis of responses from both arbitra- tors and counsel, the same individuals often donning both hats (Section A). The se- cond part, similar to (Section C), analyses the responses of the single expert interviewed with extensive experience appearing in arbitration disputes (Section B).
A. Investment Arbitrators and Counsel
This subsection first provides a description of the responses of investment arbitrators and counsel (i), and is followed by an analysis of these same responses in a general context (ii).
(i) Synopsis of key features in the responses
With regard to the definition of the role of experts, whether appointed by the arbitra- tor or by the parties, there is the pervasive perception of similarity between the two, a duty being owed to the adjudicator in both cases. The few differences expressed in the answers rely on the practical consideration of implementation, but there is overall consensus on the principle that the general function of these experts is identical: pro- viding well-reasoned independent and impartial opinion. Nevertheless, some respondents seem to consider in a somewhat contradictory manner, that the party- appointed expert also has to independently support the appointing party’s conten- tion, finding ‘non-legal advocacy admissible’.
Respondents generally agree with the assumption that the use ofex-curiaexperts is not an option that should be consideredprima facie, when confronted with a tech- nical case but should result from insufficiency or difficulties with the expert evidence presented by parties. It should generally remain exceptional and be performed after consultation with parties. Its function should not necessarily be limited to reviewing the expert evidence of the parties, and the answer depends on the particulars of a case. Nevertheless, the principle remains that the expert reports of the parties consti- tute the primary material. A majority of the respondents see the overdue influence of anex-curiaexpert on the adjudicator’s findings as a legitimate issue, but believe that it could be tackled by adopting transparency measures and increasing involvement of the parties.
Independence and impartiality were mentioned by all respondents as attributes every expert should possess. However, there is sometimes confusion between and conflation of the two notions, broadly defined in economic terms, such as a shared fi- nancial interest with a disputing party. Other respondents articulated the definitions very clearly and considered their legal consequences. To them, independence could
be described as having objective links with the party, whereas impartiality refers to a state of mind. Generally, the same requirements should be applied to both types of experts. For some, in opposition to their theoretical understanding of the role of experts, a higher standard is expected fromex-curiaexperts in practice, one respond- ent stating that a party-appointed expert cannot be impartial. The assessment of in- dependence and impartiality does not appear to be an admissibility issue, but rather a question of weighing evidence. Disclosure of the instructions is considered very useful or even necessary and already constitutes best practice. A respondent specified that disclosure of oral instruction could be useful, but difficult both in practice and le- gally (as privileged communication).
The importance of oral examination of experts who have submitted a written tes- timony, ranges from important to indispensable. Cross-examination works without a precise procedural framework because according to the respondents, it is important to maintain flexibility in the process, and operates efficiently with common experi- ence and background in arbitral culture of the counsel, arbitrators and other such participants in the arbitration.
Respondents consider that judges should be proactive in managing the evidence, through different techniques (ordering joint report of party-appointed experts, ex- curiaexpert reports, experts commenting on each other’s reports or considering spe- cific issues), but not at the outset of the proceedings. Narrowing down the issues dealt with by experts is deemed a good principle, for example with joint reports, but the decision to conduct the discussions, and the opportune time for these discussions should not be left to the appraisal of the experts. The effectiveness of the process would depend on the extent to which experts properly engage with each other in a bona fide, impartial way, without interferences from counsel. The assessment of the effectiveness and utility of the ‘expert teaming’ technique, is diverse, ranging from helpful to useless. More generally, only some respondents found an increase in the use of new methods in international arbitration even if most of them considered them useful. Concerning the management of evidence, the respondents seem reluc- tant to accept a strict understanding of theactori incumbit probatiorule, a rule that requires the arbitrator, when unable to effectively assess the parties’ evidence, to ad- judicate in favour of the defendant.
The practice of using internal expertise is considered inappropriate, and possibly at odds with due process requirements. It is however seen as possible in very excep- tional cases such as practical implementation of legal conclusions, in boundary cases, for instance. Some respondents do not see this involvement as problematic since the expert is not participating in the deliberations or providing new evidence (again referred to as assessors). Mention was also made of the possibility for the adjudicator to appoint an assessor, an entity which is not used in international arbitration.
The possibility of formulating and applying a code of conduct is considered gen- erally helpful, but respondents consider that it should remain in the form of general guidelines, rather than a detailed code.
(ii) Analysis of responses in general
The answers provided were characterized by two main features: the technical and detailed nature of many responses on the one hand, and the circumstantial character of these answers on the other, reflecting the inherent flexibility of the arbitral proced- ure. Some distinct trends can be seen in these responses. Some respondents appear to have given much thought to the problematic of experts in international adjudica- tion and seem very well-informed. This is not to say that there are unanimous opin- ions, in fact those are rare. However, the opinions are detailed enough (in many cases) to show the existence of a debate. Indeed, the answers seem to be generally informed by extensive practical experience. A more theoretical level of thought if pre- sent, is not merely in the abstract, because it relies on examples and precisely described legal institutions. Some respondents provide case-law in support of their arguments and discuss provisions from different bodies of arbitration rules. In the ar- bitration field, the familiarity with the expert and related legal institutions make the differences of opinion between these respondents less explicit and minimizes the im- portance of legal culture or professional background. While this common base does not preclude clear-cut oppositions and dissimilar perceptions or opinions, the per- spectives adopted are not completely unrelated and permit avoidance of parallel dis- courses, a phenomenon observed with some of the respondents to the ICJ questionnaire.
The importance of flexibility is emphasized throughout the questionnaire, respondents regularly highlighting the importance of adapting the expert process to the nature of the case. The respondents take care not to be dogmatic in their answers, and barely express themselves in terms of absolute solutions. One respond- ent even states in response to most questions, almost systematically, that his answer depends on the specifics of each case.
The result of the conjunction of these two trends is the pragmatic approach pre- vailing in international arbitration. Consequently, the possibility of using ex-curia experts is contemplated, and there is no systematic disregard for the use of some in- quisitorial methods by the arbitrator. There is no ‘claimed’ fundamental opposition between a common law approach and techniques in line with the civil law tradition.
Generally speaking, the proactive attitude of the arbitrator in managing the evidence is seen as very advisable. However, the point of view adopted could be perceived as somehow originating in common law, as the role of the expert appointed by the tri- bunal is merely understood as revising parties’ expert reports or enlightening the tri- bunal on the evidence submitted by the parties, and not to proceed to its investigation which will base the adjudicator findings. In addition, the comprehensive involvement of the parties in an adversarial fashion into the work of theex-curiaex- pert appears to be unknown.
The pragmatic approach is also reflected in the perception of the burden of proof, seemingly driven by no clear established principles. The handling of the allocation of the burden is rather determined by the nature and quality of the facts, the evidence contemplated and the circumstantial perception of the adjudicator. In this regard, there remains an uncertainty regarding the kind of justice (inquisitorial or adversar- ial) towards which the international arbitration process is leaning.
Another distinctive feature in international arbitration appears to be the import- ance of the ‘individual’ factor. The personality of the actors and their behaviour are elements taken into consideration with respect to the relevance of a certain proced- ure, along with a strong implication of the trust vested in the somewhat closed com- munity of players in international arbitration. Indeed, several responses referred to the good will of the judicial actors as well as their knowledge of the procedure or their sincerity in commitment to a common work.
Also of particular note is the lack of clear answers regarding the question of ad- missibility of expert evidence. It seems that lack of independence of an expert is more a question of the weight to be given to evidence than admissibility. The lack of intelligibility in the answers for such a question is surprising, considering the import- ance of the procedural consequences conveyed by the choice between the two alter- natives. A similar conclusion can be drawn for the definitions of independence and impartiality of the expert. Responses are at least dissimilar, some of them even being in clear opposition. For example, the ‘expert-counsel’ performing non-legal advocacy is seen by different respondents as either unacceptable or conversely, appropriate.
Finally, the practical approach in arbitration seems to, on some occasions, impede a systemic understanding of some broader concepts, such as the judicial function, which varies depending on the specificities of the case considered. Indeed, the casuis- tic methodology adopted towards procedural problematics, and thesui generissolu- tions generally advocated by the respondents, make unclear for instance the principles driving the allocation of powers between the judge and parties as to fact- finding. As mentioned earlier, the inquisitorial or adversarial character of the proced- ure (a question directly related to the adjudicator’s function) seems to be varying according to the particular circumstances of the case.
B. Investment Arbitration Expert
As with ITLOS, this subsection focusses on the views expressed by one expert with extensive experience in the arbitration field. This expert appeared before major arbi- tral institutions such as ICSID, ICC, LCIA, Iran–US Claims or several Panels of Commissioners at the UNCC. He shared his thoughts about his experiences as ex- pert appointed by both tribunal and parties.
According to the respondent, with regard to the different functions of experts, the party-appointed expert has to ‘support the opinion evidence in such a way as to facili- tate the tribunal’s finding on the debated technical question’. When the expert is appointed by the tribunal, his/her role is to ‘translate the technical reports and opin- ions of the party-appointed experts so as to facilitate understanding’ by the tribunal members. The respondent made clear that be it for theex-curiaexpert or the party- appointed expert, the overriding obligation is to the tribunal. In other words, the function of an expert is to provide help to the adjudicator in understanding complex facts or evidence.
The respondent identified independence and impartiality as fundamental require- ments to acting as an expert, whatever the capacity in which he/she is involved in the procedure. He distinguished between these two qualities by considering that in- dependence manifests itself when a party-appointed expert acts with freedom and in