Jackson LJ advocates increased usage of concurrent expert evidence or “hot tubbing” in England and Wales, primarily based on anecdotal experiences of trial time, costs savings and the facilitation of the writing of judgments.
The process has been common in Australia in competition, land and environment cases for many years. It has become the default position in a broader range of claims over the past ten years, for example in common law claims in New South Wales.
So is hot tubbing good, bad or the curate’s egg? To mix metaphors further, where you stand depends on where you sit.
Judges in Australia almost invariably support it, most commonly as a constraint on experts behaving as advocates, and to assist in distilling complex competing views. However, even for judges the process has its limits. For example, in one of the largest cases ever run in the Federal Court of Australia, the C7 case, the judge decided against concurrent competition expert evidence on the basis that there were too many experts (six) for the hot tub process to generate more light than heat.
On the other hand, in the more recent Federal Court smartphone wars litigation between Apple and Samsung (which broke C7’s hearing time record), the judge required all evidence from an army of discrete competition, technology, patent, licensing, standards organisation and foreign law experts to be given concurrently, platoon by platoon. Three aspects of the approach deserve consideration.
Firstly, the process certainly saved hearing time as strict time limits were imposed on the parties and experts. However, it did not save costs. That was because enormous resources were required to be devoted to additional pretrial processes of attempting to agree on joint questions, followed by expert conferral and joint reports. All of those stages were highly contentious. Even the process of coordinating experts to confer, and the process of arranging their simultaneous appearance, was fraught. It increased cost by delay and interference with the trial timetable.
Secondly, the trial judge strongly encouraged the parties throughout pretrial stages and during the trial to narrow the issues for determination. This was to ensure that those issues remained consistent with the overarching purpose of court procedure, that is, just resolution that is as quick, inexpensive and efficient as possible. In practice, the concurrent evidence process generated a Brazilian rainforest’s worth of additional questions and reports (and objections and qualifications to questions and reports), but in general it did not generate significant common ground to limit the issues.
Thirdly, the judge firmly believed that the process was necessary to facilitate her understanding of the issues and evidence. That was certainly true in part; for example, it was invaluable in understanding the complex technology involved. However, a contrary argument can be put in relation to some aspects of the evidence.
Speaking more generally, rather than on specific matters in contention, there is a risk in the hot tub process of one expert dominating by force of personality and experience. This could result in he or she finding favour with the court. That is because, to a large extent, the process removes the ability of the parties to test fully, through orderly individual cross-examination, the bases and rationale for the expert’s opinions. The less formal conversational and inquisitive processes of the hot tub can lack the rigour of cross-examination.
Equally, effective judicial supervision of the process can be very limited when the judge does not have sufficient knowledge of the expert area. In that event, the process may only work effectively if an expert is appointed by the court to assist in supervising the process. Although that facility is available in Australia (as is the appointment of a court expert more generally), it has not been used beyond some very specialised proceedings in practice.
From where the judge sits in Australia, hot tubbing is good. From where counsel stands or instructing solicitors sit, the process is more curate’s egg. My own view is that where issues are at the less complex end of the spectrum, and quick efficient resolution is paramount, more use should be made of a court appointed expert, even at the expense of expert witnesses for the parties. Both parties could examine the court appointed expert fully, with the assistance of their own party expert if necessary.
At the more complex end of the spectrum, and in civil penal or criminal prosecutions, case management principles, to an extent, can and should give way to the parties’ rights. In that context there is no effective substitute for the traditional adversarial system of expert evidence presented by each party and tested by unconstrained cross-examination.