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Concurrent Expert Evidence - The Way Forward?

Posted on 5th April 2011

There are various ways in which expert evidence can be given to a court. Concurrent evidence may become one of the options. Richard Walmsley discusses some of the key elements associated with this process.

Concurrent evidence, colloquially referred to as ‘hot-tubbing’, may become one of the ways in which expert evidence can be presented. This option, and others, are described at paragraph 13.8.2 of The Technology and Construction Court Guide, Second Edition, Second Revision, October 2010 (‘the Guide’) which I reproduce below:-

“The way in which expert evidence is given is a matter to be considered at the PTR. However where there are a number of experts of different disciplines the court will consider the best way for the expert evidence to be given. It is now quite usual for all expert evidence to follow the completion of the witness evidence from all parties. At that stage there are a number of possible ways of presenting evidence including:

(a) For one party to call all its expert evidence, followed by each party calling all of its expert evidence.

(b) For one party to call its expert in a particular discipline, followed by the other parties calling their experts in that discipline. This process would then be repeated for the experts of all disciplines.

(c) For one party to call its expert or experts to deal with a particular issue, followed by the other parties calling their expert or experts to deal with that issues (sic). This process would then be repeated for all the expert issues.

(d) For the experts for all parties to be called to give concurrent evidence, colloquially referred to as “hot-tubbing”. When this method is adopted there is generally a need for experts to be cross-examined on general matters and key issues before they are invited to give evidence concurrently on particular issues. Procedures vary but, for instance, a party may ask its expert to explain his or her view on an issue, and then ask the other party’s expert for his or her view on that issue and then return to that party’s expert for a comment on that view. Alternatively, or in addition, questions may be asked by the judge or the experts themselves may each ask the other questions. The process is often most useful where there are a large number of items to be dealt with and the procedure allows the court to have the evidence on each item dealt with on the same occasion rather than having the evidence divided with the inability to have each expert’s views expressed clearly. Frequently, it allows the extent of agreement and reason for disagreement to be seen more clearly. The giving of concurrent evidence may be consented to by the parties and the judge will consider whether, in the absence of consent, any particular method of concurrent evidence is appropriate in the light of the provisions of the CPR.”

(Emphasis added)

My experience of giving expert evidence is that option (b) of paragraph 13.8.2 of the Guide is generally followed. Therefore, when witnesses of fact have completed their evidence, experts of like discipline give their evidence sequentially. In this way the expert evidence of like disciplines is fresh in the mind of the judge.

However, the Guide also proposes, as an option, a relatively new method of presenting expert evidence by reference to concurrent evidence. This adopts the recommendations of the Right Honourable Lord Justice Jackson at Chapter 38, paragraphs 3.23 and 3.24 of the Review of Civil Litigation Costs: Final Report (‘the Review’). The Review recommends that concurrent evidence is piloted, subject to consents of the various participants. If the results of the pilot are positive, then consideration could be given to amend CPR Part 35 in order to provide concurrent evidence in appropriate cases.

The tone of the Review, and subsequent Guide, suggests to me a slightly cautious approach to the implementation of concurrent evidence. I therefore describe below the key issues associated with concurrent evidence and my own observations.

The Guide contemplates, as an option, the existing adversarial system being integrated with concurrent evidence. The process in such circumstances appears to be that experts would first be cross-examined in the normal way on general matters and key issues. The experts would then participate in giving concurrent evidence on particular issues. Whilst this procedure might vary, a sensible approach would seem to be:-

  • experts of like discipline sit in front of the judge and give evidence at the same time in each other’s presence.
  • experts would explain their position, ask each other questions, responding as appropriate.
  • experts would also be asked questions by the judge.

It could be argued that the concurrent debate between experts is likely to assist the judge by making the experts respective positions more transparent. It could also be the case that combining the adversarial system and concurrent evidence provides a balance that will assist the court.

Concurrent evidence needs well prepared and effective experts who are capable of explaining, in simple and concise terms, the complicated issues that are in dispute between the parties. Partisan experts will be exposed and, as a consequence, the parties need to consider selection of its experts carefully where there is the potential for concurrent evidence. This is likely to lead to an increase in the calibre of experts which can only be of benefit to the parties and the court.

Concurrent evidence could be viewed as a forum where sensible, pragmatic experts work together in order to assist the court. That is their primary duty in any event. Alternatively, it could be viewed as an intrusion into the adversarial system, where barristers lose control and the balance of the process is changed.

What is important, in my view, is that the perceived savings in cost and time associated with concurrent evidence, which after all are driving this potential change, are balanced against the risk of rough justice. By this I mean that when savings in time are being contemplated, it will inevitably have consequences which might include diluting the more thorough approach that the present system allows. That is not what the parties who have chosen to litigate expect.

However, if the current adversarial system remains in place but concurrent evidence is additionally adopted for specific issues, appropriately controlled, then the benefits of both procedures might be realised. It remains to be seen what costs are in fact saved by the introduction of concurrent evidence. If experts are first cross-examined on general matters and key issues and then invited to engage in concurrent evidence, as envisaged by the Guide, there would not appear to be the opportunity for cost savings of any real magnitude unless the process of cross-examination is shortened.

It will be interesting to see how any pilot schemes for concurrent expert evidence are received and whether it then becomes a regular feature.

For further details, please contact Richard Walmsley:

Gardiner & Theobald Fairway Limited
Met Building, 22 Percy Street,
London, W1T 2BU.
Tel: + 44 (0) 20 7209 8400
Fax: + 44 (0) 20 7209 8450

email@gtfairway.com