UK: Hot Tubbing

Last Updated: 21 April 2010

The Jackson Report on litigation costs included some novelties, for example the concept of "hot tubbing".

Hot tubbing or "concurrent evidence", is a method of giving evidence where both experts give evidence simultaneously and the court or tribunal chairs a discussion between them. Hot tubbing is regularly practised in Australian Courts and international arbitration proceedings, where it is often used after cross-examination.

In his Final Report, Jackson LJ recommended that hot tubbing should be piloted in cases where all parties and the judge agree to it. This has the potential not only to save costs but to improve the quality of court decision making.

How does it work?

Although the format of hot tubbing differs from case to case the basic approach is that experts are sworn in at the same time and the judge chairs a discussion between them. The pre-trial documents (recording the matters upon which the experts agree/disagree) serve as the agenda. Counsel is able to join in the discussion and can put questions to the experts, as and when permitted by the judge. In addition, the experts can put questions to each other.

The theory is that experts are more likely to make concessions and reach a greater degree of agreement in the hot tub than through cross-examination. In the hot tub, experts are more relaxed and can therefore take part in a more constructive discussion.

Experts often answer questions at the same time and so hot tubbing is effective in helping to identify areas where the experts truly disagree. Unlike cross examination, the experts in a hot tub scenario are asked broad questions which generally seem to elicit helpful answers.

Also, as each expert is subject to simultaneous peer scrutiny, the risk of misleading answers is reduced and so any inaccuracies should be picked up immediately. If there is any confusion or uncertainty, the experts can be asked questions straight away to clarify an issue.

Pros and Cons

Hot tubbing has a number of advantages:

  • It saves both time and costs. Instead of counsel turning round to take whispered instructions during cross-examination, counsel can now put his questions to the experts in the hot tub. Both/all experts can then deal with that particular point.
  • Experts can properly help the court to resolve disputes
  • Hot tubbing does away with the "one on one" gladiatorial combat between cross-examining counsel and each expert
  • From the experience of the Australian courts, it would seem that overall, the procedure works well, especially where the experts know and respect each other.

But there are also disadvantages. Where the experts do not know or respect one another's expertise or where there is a suggestion that an expert is not acting in good faith, hot tubbing may not work. Or, time may be wasted as the experts go round in circles or digress from relevant issues. From the practitioner's perspective a concern is loss of control. An expert may lose his concentration and may also lose the fear that he would experience under cross examination. This may lead him to make concessions that he would not make if he was in the box on his own (and would not make if he thought about the question properly). To reduce this risk, experts need to be thoroughly prepared for the hot tub.

If there is no cross examination, as the Jackson report seems to suggest, there is a risk that counsel will not have the opportunity to make all the points that they would like to make, particularly if questions from the advocates are not permitted as part of the process. There is also a risk that key documents might be missed if the advocates cannot bring them to the attention of the court.

Will hot tubbing work for me?

You should consider "hot tubbing" if:

  • You have a strong case and your expert is confident and persuasive (especially where you know he will come across better than the other expert – weak experts can easily be exposed in the hot tub).
  • Your expert has had previous experience of being in the hot tub (especially if his opposite number hasn't).
  • The issues in dispute are complex and you want to give your expert a chance to explain his theories.

Where it comes down to a simple choice between the hot tub or cross examination, it might be best to steer clear of the hot tub where the credibility of your opponent's expert is in issue. Here a tough cross examination will probably be more advantageous.

The extent of hot tubbing in the UK courts will depend on the approach taken by any pilot. This firm intends to become involved in the pilot project so watch this space.

Tim Constable comments – as with the concept of single joint experts, hot tubbing sounds superficially attractive but in reality it is dangerous for the parties – one wrong comment in this notionally relaxed atmosphere could spell doom for an otherwise meritorious case. Consequently, experts will be inclined to clam up which rather defeats the purpose.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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