Expert Testimony in International Arbitration: How Decision-Makers Evaluate Science and Technical Evidence

In complex commercial and international disputes, expert testimony often plays a decisive role. Yet arbitrators and judges are rarely specialists in the scientific, financial, or technical disciplines presented to them. How, then, do decision-makers assess competing experts and how reliable is that assessment?

This panel examines expert evidence through the lens of decision science, psychology, and comparative procedure. Drawing on research in cognitive psychology and behavioral decision-making, the discussion will explore how adjudicators process complex expert testimony, the risks of cognitive biases, and how procedural design influences evidentiary evaluation.

Panelists will address:

• How arbitrators evaluate conflicting expert opinions in highly technical disputes

• The impact of cognitive biases and heuristics in weighing expert credibility

• Whether procedural mechanisms such as “hot-tubbing” (concurrent expert evidence), tribunal-appointed experts, or written expert conferencing improve comprehension and reliability

• Differences between civil law and common law approaches to expert evidence

• Practical strategies for counsel in presenting and testing expert testimony

• Techniques arbitrators can use to ask more effective questions and structure expert proceedings to enhance clarity

By combining academic insight with practical experience, this session will provide actionable guidance for improving the evaluation of expert evidence in international arbitration and complex disputes more broadly.