Experts ease their tensions in the hot tub

By Andrew Stephenson and Andrew Barraclough.

Key Points:
Victoria's Supreme Court has introduced a new practice for the hearing of expert evidence, commonly known as "hot-tubbing", which allows it to hear expert witnesses of opposing sides at the same time.

In order to create a more cost and time efficient procedure for hearing expert evidence, the Victorian Supreme Court has recently amended its Practice Notes to allow for the "hot-tubbing" of expert witnesses. Hot-tubbing is a procedure for hearing expert evidence that involves multiple experts presenting their evidence at the same time, in a panel format.

The traditional way in which expert evidence is heard is that each party calls its expert during its case. This means the expert evidence is heard amongst the factual evidence for the party calling the expert. Accordingly, the opposing expert witness may not be heard for weeks or months (in a complex matter) after the first expert evidence is heard. Hot-tubbing separates the expert and factual evidence. The factual evidence is heard first in a conventional way. Then each discipline of expert evidence is heard together with both sets of experts giving presentations back to back.

The hot-tub process in Victoria is a variant of the joint conferencing of experts first developed by Justice Lockhart in the 1970s in the Australian Competition Tribunal (or the Trade Practices Tribunal, as it was then called) and adopted for use in the Federal Court. Since then it has been used in international arbitration.

The procedure is flexible and will vary depending on the number of experts involved. Typically it begins with each side's witness giving a brief oral exposition (written statements will have been exchanged and provided to the court prior to trial). The other side's expert (ie. not counsel) will then question the first expert. Then the process is reversed. Each expert then gives a brief summary.

Counsel is usually not allowed to intervene until this procedure is complete. They may then cross-examine and re-examine the witnesses in the conventional way.

When successful, the procedure should create the environment of a colloquium or round-table discussion. In the Federal Court and abroad it has given rise to the following advantages:

• by exchanging questions, witnesses can often explore an issue until it is clear, or until it is clear why diverging opinions exist;
• without the questioning from counsel, the environment becomes less confrontational, which makes it easier for witnesses to concede a point without losing face and credibility;
• when experts need to justify their opinions to fellow experts, extreme views are usually moderated;
• peripheral issues are more readily recognised and isolated as being unimportant;
• when removed from the camp of the party who called them, experts have tended to be less partisan;
• a discussion led by experts can often be more sophisticated than a discussion led by counsel who are less-well versed in the relevant specialised field;
• it is easier for the judge to recall and compare the positions of the experts when they are heard together, rather than if they are heard separately, perhaps weeks apart, during which time positions and assumptions may have been qualified;
• it can save time: in a major and often-cited predatory pricing case (Australian Competition and Consumer Commission v Boral Ltd [1999] FCA 1318), the lay evidence took some four weeks, however the expert evidence of two economists, which was fundamental to the whole case, took only one day; and
• after witnessing the hot-tub process the parties understand more clearly the strengths and weaknesses of their positions, which can be conducive to settlement.

One drawback of the procedure is that it limits parties' ability to call expert evidence in the manner they choose. When a direction in favour of hot-tubbing is made by the Court (which, according to the Supreme Court's Practice Notes, will only occur in "appropriate circumstances"), parties will be unable to have witnesses heard in the traditional fashion.

In the context of international arbitration, where hot-tubbing has also been used for factual witnesses, it has also been suggested that witnesses may be influenced by listening to each other, potentially affecting the freshness of their testimony. In the Supreme Court of Victoria, however, such a danger is unlikely. The practice will only be used with expert witnesses, whose evidence is based on professional opinion and experience, not on their recollection of a particular event. It will also have been the subject of a written statement. As such it is unlikely to be easily influenced by listening to other experts during the hearing.

Another recognised drawback is that some experts, when asking their colleagues questions, try to act as counsel. By hostilely cross-examining, rather than questioning their colleagues in a professional manner, they reintroduce an adversarial environment which defeats the purpose of the procedure. Such an approach by an expert is likely to be counterproductive as the tribunal is more likely to see an expert that engages in such activity as an advocate rather than an independent expert, and discount that expert's evidence as a consequence.

However, it is expected, and has been shown locally and overseas, that the benefits of hot-tubbing generally outweigh its drawbacks, and that skillful lawyers who adapt quickly to the new procedure can minimise the potential for difficulties to arise.

As a move to streamline the resolution of commercial disputes, the introduction of hot-tubbing in the Victorian Supreme Court is to be commended. It is expected to attract considerable interest from other Australian jurisdictions.

For further information, please contact Andrew Stephenson.