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Following Virginia Jones’ brief and initial report on the CJC’s study on concurrent expert evidence, Maura McIntosh, a professional support consultant in the dispute resolution team at Herbert Smith Freehills and deputy chair of the Civil Litigation Review working group, explains in greater detail the findings and proposals of that working group in relation to concurrent expert evidence.
Concurrent expert evidence, or hot-tubbing, was formally introduced into English litigation in April 2013 as part of the Jackson reforms. As described in Practice Direction 35.11 (CPR PD 35.11), where the procedure is adopted, the experts in a particular
discipline are sworn in together and the judge leads them through a discussion on the issues set out in a pre-set agenda, which is based on the areas of disagreement identified in the experts' joint statements.
Following the introduction of hot-tubbing, however, there was by no means a rush to embrace the technique—while not exactly empty, the hot-tub was certainly not crowded either. The general perception in the legal community was that hot-tubbing was
being rarely used, despite its endorsement by Lord Justice Jackson and favourable accounts by a number of judges who had experience of the technique.
Prompted, in part, by this perception of a reluctance to adopt the technique, the CJC was asked to undertake a review of concurrent expert evidence and its use in English litigation since the Jackson reforms. The review was undertaken by a working group
chaired by Professor Rachael Mulheron of Queen Mary University of London, with myself as deputy chair, and the working group's report was published on 1 August 2016.
As part of its review, the working group conducted surveys of judges, legal practitioners and expert witnesses who had experience of hot-tubbing, whether in English court proceedings or in litigation elsewhere or in arbitration. Close to 100 responses
were received. The working group also conducted interviews of judges and others with relevant experience, as well as benefitting from the insights of working group members who were selected for their experience in this area.
Lord Justice Jackson identified four objectives for the use of hot-tubbing in his November 2011 lecture on 'Focusing Expert Evidence and Controlling Costs'. These are broadly summarised in the working group's report as:
It is clear from the feedback obtained by the working group that hot-tubbing can save significant amounts of time at trial, compared to traditional cross-examination. Judges who responded to the survey were unanimous in this view, though legal practitioners
and expert witnesses were less so (at 56% and 74% respectively)—that may be explained, to some extent, by the fact that a number of survey respondents indicated that hot-tubbing was used in their cases in addition to traditional cross-examination,
rather than a substitute for it. Even where trial time is saved, however, it does not necessarily mean a saving of judicial resources, as hot-tubbing requires the judge to devote more time to the case before trial, in order to become sufficiently
familiar with the issues to be able to lead the questioning effectively.
The feedback also showed very strong support for the notion that concurrent evidence improves the quality of the expert evidence and assists the court to determine disputed issues of expert evidence. The vast majority of judges and legal practitioners
who responded to the surveys responded positively on both points (approximately 84% believing quality was improved and even more that the court was assisted—100% of judges and 94% of legal practitioners). Support among expert witnesses was less
consistent, but still positive, with 59% considering that hot-tubbing improved quality and 71% that it assisted the court.
Surprisingly, however, only a minority of respondents from all three categories (33% of judges, 28% of legal practitioners and 45% of expert witnesses) considered that hot-tubbing had led to a saving of costs for the parties. The reasons for this rather
counter-intuitive result are not clear, particularly given the majority view that time at trial was saved. The working group report suggests that some further exploration may be warranted in future to understand the reasons for this perception and
address the concerns.
Currently CPR PD 35.11 sets out one procedure that may be followed where the court directs that expert evidence will be given concurrently (while recognising that the judge has a discretion to modify the procedure). This is the procedure most people understand
by the term 'hot-tubbing', though that term is not one that generally finds favour. The working group report suggests the alternative label 'judge-led joint examination of experts' (or JJEE) as it is the judge that takes the driving seat and leads
In practice, however, this is by no means the only procedure by which expert evidence may be given concurrently. A distinct process identified in the report is termed 'sequential "back to back" evidence'. This is a form of concurrent evidence, as the
experts are sworn in concurrently, but it is not judge-led in the way hot-tubbing is. The advocates for the parties lead the questioning in a more traditional way, with each expert giving evidence and being cross-examined on the first issue, and then
repeating the process for the second issue, and so forth – rather than the experts giving the whole of their evidence separately.
There are also various hybrid versions, in which judge-led questioning and more traditional cross-examination may be combined, either generally or by reference to particular topics.
In addition, although it is not a form of concurrent expert evidence, the working group also noted a 'teach-in' approach that may be used, in essence, to educate the court on the technical issues arising in the case. This may be through the appointment
of a neutral adviser, or it may be the experts instructed by the parties who provide the judge's tutorial or 'teach-in'.
The working group took the view that it would be appropriate to revise the Practice Direction (PD) to reflect this variety of techniques that may be used. The report sets out a suggested re-draft which the Civil Procedure Rule Committee (CPRC) is invited
The working group also considered that there would be merit in drafting a guidance note for judges and practitioners in order to supplement the revised PD on various issues. The report sets out a suggested draft, which deals with various issues including:
This last point, regarding the potential for cross-examination as part of the hot-tubbing process, arises in part from a perceived concern by some parties and their legal representatives that hot-tubbing may not allow them a sufficient opportunity to
test the opposing experts' views.
Given the importance of this procedural issue in deciding the outcome of the litigation, the working group considered that it might be useful for the court to consider whether counsel should be invited to ask questions at the conclusion of the judge-led
questioning on each topic, rather than at the overall conclusion of the hot-tubbing session. The report notes this 'may reduce the risk of the parties' feeling that the opportunity to test points had not been properly provided' (page 50).
Cross-examination is also addressed in the suggested re-draft of CPR PD 35.11, which states that as part of the JJEE process, and after the judge-led questioning has been completed for any issues (or all issues) the judge may invite the parties' representatives
to ask questions of the experts. The draft continues: 'Such questioning should be directed towards: (a) testing the correctness of the expert's view; (b) seeking clarification of the expert's view; or (c) eliciting evidence on any issue (or on any
aspect of an issue) which has been omitted from consideration during the [judge-led questioning]', though it should not cover ground which has been fully explored already.
In addition to the suggested amendments to the PD and the new guidance note for judges and practitioners, the report also recommends:
It is now for the CPRC to decide whether CPR PD 35.11 should be amended to reflect the working group's recommendations, and what form any amendments should take. The other recommendations, including the guidance note for judges and practitioners and the
information note for experts, will follow on from that process.
Although the timing is not clear, it is hoped that these matters might be taken forward soon after the summer holiday period, to build on the momentum the working group's report has generated.
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