The case for concurrent evidence

According to the Hon Justice Peter McClellan, Chief Judge at Common Law Supreme Court, concurrent evidence is “a discussion chaired by the judge in which the various experts, the parties, the advocates and the judge engage in a co-operative endeavour to identify the issues and arrive where possible at a common resolution of them. Where resolution of issues is not possible, a structured discussion, with the judge as chairperson, allows the experts to give their opinions without the constraints of the adversarial process and in a forum which enables them to respond directly to each other. The judge is not confined to the opinion of one adviser but has the benefit of multiple advisers who are rigorously examined in public.”

The role of an expert witness in litigation is to assist the decision-maker in fact-finding by applying specialised knowledge to the evidence and proffering an opinion on the issues in dispute. The complexity of this task is often exacerbated by the fact it is a retrospective inquiry, and the evidence presented often is inconsistent or critical facts are disputed. It is not surprising, therefore, that differences of opinion are likely to arise.

Where this happens, a joint report of experts arising from a private meeting, or conclave (usually a precursor to concurrent evidence if the matter proceeds to hearing), is able to provide short reasons for matters of disagreement by excluding lengthy discussion on the applicability of agreed literature, for example. Short reasons for matters of disagreement established in the expert conclave have the potential to streamline the evidence adduced from experts in court as well as aiding settlement negotiations. Those efficiencies can be furthered by the concurrent evidence process in the courtroom.

From an expert’s perspective, under the traditional procedure, cross-examination provides limited opportunities for an expert to provide detailed explanations outside the confines of the questions. The questions may concentrate on points regarded as peripheral or irrelevant by the expert at the time of questioning. The point of a particular line of questioning may not be immediately apparent to the expert until it is too late, by which time the opportunity to recover lost ground may not present itself.

Another disadvantage is that each expert presents their evidence sequentially, and it could be days or even weeks between examinations. Expert evidence should deal with all relevant matters and should be presented in a well-considered manner, with appropriate weight given to each component of the opinion. There is no doubt that the cross-examination process leaves experts dissatisfied with the manner in which their opinions have been distorted or unbalanced as a result of emphasis on trivial or minor points of interpretation.

Concurrent evidence has the potential to allow expert evidence to be more useful to the court by enabling the experts to question the evidence of the other experts as it unfolds during cross-examination or commentary.

A further benefit of concurrent evidence is that the dynamics in court tend to reinforce the precept that an expert’s role is to assist the court. This is partly a matter of atmospherics and partly a result of the weakening of the traditional adversarial feeling engendered by cross-examination in which the expert may be influenced to defend the opinions rather than concede points that should be conceded.

The success or otherwise of concurrent evidence depends on the judge’s approach and court management. The mechanics of the concurrent evidence vary, depending on the differing approaches of judges. In some cases, the two or three experts will be asked to sit at the bar table, with counsel moving to the side. In other cases, the judge may leave the bench to sit at the bar table, next to the experts. In some cases the experts sit together at the witness stand. If numerous experts are involved, they may sit together behind the bar table or to the side, depending upon the available space and furniture arrangements.

Depending upon the system established by the judge, elements of traditional cross-examination by counsel may be retained within the concurrent evidence process. In some cases, the judge invites experts to comment on answers given by other experts during cross-examination.

From an expert’s point of view, an advantage of concurrent evidence is that the expert is able to provide an immediate critique of the other expert’s evidence.  No matter how skilled and well prepared counsel may be, it is unlikely they will be as well-equipped as an expert to test all technical aspects of the evidence on the run. In traditional cross-examination, an expert may be able to pass notes to counsel or make sotto voce comments to counsel with explanations or suggestions for further questions, but that process has its limits. In concurrent evidence, there is the possibility of experts directly commenting on and questioning the evidence of other experts.

In summary, the potential advantages of a conclave followed by concurrent evidence are:

• Refinement of areas of difference, with streamlined reasons for the differences in the joint conclave report stripped of the detailed explanations common in individual reports.
• In court, concurrent evidence provides the opportunity for that exchange of opinions to be continued under the surveillance of the judge, with the assistance of modified cross-examination segments in which experts are able to intersperse their comments and questions.
• In time, apart from potential efficiencies in the hearing itself (partly or wholly offset by costs incurred in preparation for and conduct of the conclave), a significant benefit in the processes of conclave and concurrent evidence may be reinforcement in the minds of experts of the precept that their purpose is to assist the court.