Expert Hot Tubbing in International Arbitration: Panel and Live Demonstration

On 7 July 2026, at Latham & Watkins’ London office, seasoned and young arbitration practitioners came together to see expert witness conferencing – commonly known as “hot tubbing” – brought to life through a live demonstration. 

The evening was jointly organised by the CIArb Young Members Group London Branch, Latham & Watkins and Analysis Group, and sponsored by Latham & Watkins and Analysis Group. The aim was to move hot tubbing from theory into practice: many practitioners have come across the term, but far fewer have actually seen how the order of questioning is managed, how the experts engage with one another, how counsel protects the client’s position, and how the tribunal keeps the exercise fair and productive.

Together, the panellists offered both an expert and a counsel lens on how concurrent expert evidence functions in practice, the reasons tribunals turn to it, and what can succeed or fail once experts are put in dialogue with one another before a tribunal. Speaking were Ms. Jessica Resch, Principal at Analysis Group who acts as a testifying expert on valuation, damages and finance issues; Mr. Joshua White, a Managing Principal at Analysis Group and a consulting and testifying economist; and Ms. Shreya Ramesh, Associate at Latham & Watkins, working within the firm’s International Arbitration and Public International Law practices. 

The panellists covered: 

• An overview of expert witness conferencing itself, and why it emerged as a means for tribunals to hear opposing expert views together.  
• The range of conferencing formats – tribunal-led, witness-led and counsel-led.
• A fictional case study centred on a falling-out between the co-founders of an edtech venture, which raised questions of causation, user diversion and the right methodology for quantifying damages. 
• Two live run-throughs of that scenario: one tribunal-led, with the tribunal driving the questioning issue by issue, and one expert-led, with the experts themselves taking a more active hand in presenting and challenging each other’s views. The demonstrations provided a side-by-side comparison of effective and less effective conferencing techniques illustrating why tribunal preparation, a defined agenda and firm oversight of the process matter in preventing the discussion from becoming disorganised or lopsided.

Among the takeaways for practitioners looking to run expert conferencing well:

• Groundwork matters. Where a tribunal has not read the expert reports closely enough to pin down what it needs to understand, and has no agenda or set of targeted questions, the session can easily lose all shape. 
• Control has to sit with the tribunal. The technique only works if the tribunal actively shapes and steers it, rather than handing the reins entirely to the experts or counsel. 
• Precision beats generality. Vague, open-ended prompts risk leaving the expert evidence “passing like ships in the night”, while breaking the discussion down topic by topic helps isolate where the experts genuinely part ways.
• A good conference should sharpen the dispute, not merely showcase it. The goal is for the tribunal to come away with a clearer sense of the genuine areas of agreement and disagreement, rather than plenty of “heat but no light”.

Feedback from those in the room – spanning practitioners just starting out to well-established names in the field – was overwhelmingly positive, both on the format chosen and on the substance covered. The energy in the room throughout, and the conversation that carried on into the networking drinks afterwards, showed just how much both newer and more experienced practitioners valued seeing hot tubbing demonstrated rather than simply described.