Lest we forget: Addressing the accuracy of witness memory in international arbitration | Fieldfisher
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Lest we forget: Addressing the accuracy of witness memory in international arbitration


France, United Kingdom

Fieldfisher's Head of International Arbitration in Paris, Marily Paralika, examines new proposals put forward by the latest report of the ICC Commission on Arbitration to mitigate the effects of unreliable witness recollections in arbitral proceedings.
In its January 2021 report "The Accuracy of Fact Witness Memory in International Arbitration: Current Issues and Possible Solutions", the ICC Commission on Arbitration states:

"The time, effort and cost that are put into the collation and presentation of witness evidence are considered to be justified on the basis that they assist the tribunal reach a just decision in the case.

That justification is called into question if the witness evidence is not as reliable as the participants in the process (and most importantly the tribunal) believe it to be."

Maximising the probative value of witness testimony is a major focus for arbitration community, as this evidence is often central to arbitral proceedings.

Here, we examine the ICC Commission's report's foundations, conclusions and recommendations and consider the applications of these findings in the practical context of international arbitration.


In the last decade, scientific evidence of the unreliability of memory, which is subject to the corrupting influences of time and numerous other external factors, has begun to seriously inform approaches to witness testimony in general, including its role in international arbitration.

The report of the ICC Commission on Arbitration, which is based on the investigations of a specially commissioned Task Force, puts forward the rationale for addressing the accuracy of witness testimony in arbitral proceedings as the need to justify:
  • The time and cost involved in preparing witness statements;

  • The time and cost involved in hearing witness statements; and

  • The centrality of witness statements to the arbitrators' decisions.

It also outlines how modern arbitral practices, such as interviewing witnesses in groups, may contribute to memory distortions, based on existing and bespoke academic research on these issues.

The report further draws distinctions between research into the reliability of memory in criminal cases, which centre on recalling particular criminal acts, and the reliability of memory in arbitration cases, which typically involve remembering the content and timing of conversations and correspondence.

Section V of the report suggests measures that can be taken to improve the accuracy of witness memory.

Specifically, the report proposes ways of reducing exposure to and the effect of distorting influences, as well as possible approaches to identifying and weighing distorting influences, tailored to different types of witness/parties to an arbitration.

The ICC's conclusions and recommendations
  • Assessing the importance of witness memory to the specific case

The ICC Task Force concluded that, while desirable, the accuracy of witness memory is not always relevant in arbitration proceedings

Regardless of compelling evidence of the mutability of memory and the effect this may have on the accuracy of witness testimony, the ICC Task Force points out that fact witness testimony in arbitration proceedings often does not depend on accurate memory.

For example, in some cases fact witness evidence is simply employed to provide context or put a human face to a party’s story.

The Task Force also determined that, where accuracy is important, some of the changes required to prevent memory distortion, such as restricting access to written records or not allowing counsel to compile witness statements based on various sources, would have undesirable impacts on the overall quality and presentation of evidence in arbitral proceedings.

While the Task Force conceded that it may sometimes be appropriate to adopt measures that preserve the accuracy of witness memory (as outlined in Section V), this will depend on the specific context of the case.
  • Tribunals should not routinely concern themselves with the accuracy of witness testimony

The report outlined that while an arbitral tribunal could take various steps to reduce distortions of witness memory and evaluate witness memory in the light of distortions, including making inquiries into how witness evidence has been prepared, this should not become routine procedure.

In the ICC Task Force's view, such an approach would simply add to volume of documentation involved in arbitral proceedings and the time taken to obtain documents.

It concluded that such inquiries should be restricted to exceptional situations, based on evaluation of the importance of the witness' testimony in the context of the dispute, and the importance of determining whether or not the testimony has been affected by memory distortion.
  • The value of witness testimony must be respected

Concerns about the accuracy of witness statements have contributed to the view in some quarters that contemporaneous documents are more reliable than witness evidence.

The ICC Task Force stressed, however, that witness testimony can be valuable and important, if not vital, in arbitral proceedings.

It states that, while there is no single best practice to obtain maximum value from the available evidence, it is critical to rigorously analyse all the pertinent factors and forces that affect the individual witness' evidence, without preconceived notions as to whether documentary or witness evidence is more valuable.
  • Training and awareness is key

The ICC Task Force concluded that practitioners involved in international arbitration – including in-house counsel, outside counsel and arbitrators – can all take steps to better understand the functioning of human memory and the ensuing strengths and weaknesses of the recounting process.

Better training in this area will help mitigate the effects of memory distortion on the value of witness evidence and enable counsel and arbitrators get closer to an accurate understanding of the facts of a particular case.

The Task Force has therefore called for the provision of more training courses on this issue, with trainers to include psychologists, and the creation of a database of relevant publications to assist learning and understanding.

Our view

The purpose of the ICC report is not to take a position on the use of witness testimony in arbitration, but rather to bring to light concerns about relying on the accuracy of witness memory – in the hope that this will promote more sophisticated and consistent treatment of such evidence by arbitrators.

Despite providing an extensive list of ways in which accuracy of witness testimony can be preserved, the Task Force stresses that it does not advocate routine adherence to these steps, either by counsel or arbitrators.

What is more important is that arbitrators in particular appreciate the different purposes of fact witness testimony in arbitration proceedings and accept that its value does not necessarily lie in accuracy.

The Task Force acknowledges arguments for dispensing altogether with witness testimony in favour of documentary evidence, but echoes international arbitration expert Jennifer Kirby, who noted in her well-known speech, "Witness Preparation: Memory and Storytelling", "in many cases documentary evidence doesn't cover all the facts that are material to the dispute".

Kirby also notes the importance and power of "storytelling" by witnesses in arbitration proceedings – a function the ICC Task Force qualifies by emphasising that there are both appropriate and inappropriate ways of deploying human narratives.

The ICC report ultimately concludes there is a need to provide/improve training and spread awareness of the significant but limited value of witness testimony in arbitrations among counsel and arbitrators.

While the Task Force stops short of proposing mandatory training on this topic, it is in arbitrators' interests to be able to demonstrate interest in, and consciousness of, the nature of witness memory.

This article was authored by Marily Paralika, international arbitration partner at Fieldfisher Paris.