Concurrent Evidence (Hot-Tubbing)
Definition
A procedure used in some common-law jurisdictions, particularly in Australia and international arbitration, where opposing experts are examined simultaneously by the tribunal and by each other rather than sequentially. It often surfaces genuine areas of agreement more quickly than adversarial sequential testimony.
- Also known as
- Hot-tubbing
- Format
- Opposing experts examined simultaneously
- Common jurisdictions
- Australia, international arbitration
- Benefit
- Surfaces genuine agreement faster than sequential testimony
Common questions
How does hot-tubbing change the way an expert witness needs to prepare compared to conventional sequential testimony?+
Because experts respond directly to each other in real time rather than being examined and cross-examined separately days apart, preparation shifts toward being able to articulate the precise technical basis for disagreement on the spot, and toward genuinely narrowing the issues in a pre-hearing joint statement rather than relying on adversarial framing by counsel.
Why hasn't concurrent evidence been widely adopted in adversarial common-law jurisdictions like the United States?+
It departs from the traditional adversarial structure where each side controls the presentation and testing of its own witness, and courts in some jurisdictions have been cautious about ceding that control to a judge-led simultaneous format, even though it is increasingly used in Australia, parts of the UK, and international arbitration.
Related terms
- CPR Part 35
- The Civil Procedure Rules section governing expert evidence in England and Wales. It establishes the expert's overriding duty to the court, the...
- Daubert Standard
- The US federal evidentiary standard (Daubert v. Merrell Dow Pharmaceuticals, 1993) requiring that expert testimony be based on scientifically valid methods with...
- Expert's Overriding Duty
- The principle, codified in CPR Part 35.3 and equivalent rules, that an expert witness's primary obligation is to assist the court rather...
- Frye Standard
- The US legal test for admissibility of scientific evidence, originating from Frye v. United States (1923), which required that a technique be...
- Section 45 (Indian Evidence Act)
- The provision of the Indian Evidence Act 1872 that permits courts to consider the opinions of persons with special skill in science...