Assisting the judicial task – when should appointing an assessor be considered?

The use of expert evidence is common practice in the determination of factual issues; however, some proceedings may require highly specialised expert evidence that would facilitate the Court’s understanding of the specialist subject matter. There are some avenues that the courts have sought to overcome the hurdle presented by complex expert evidence: the use of joint experts; the use of a referee; or, as was recently decided by Lee J in McNickle v Huntsman Chemical Company Australia Pty Ltd [2021] FCA 370, appointing an assessor.

McNickle (in her own capacity and on behalf of the group members in the class action) alleges that certain Roundup products sold by the respondent increase the risk of developing Non-Hodgkin’s Lymphoma.

His Honour drew on ss 33ZF and 23 of the Federal Court Act 1976 (Cth) as conferring the Federal Court with the requisite power for such an appointment.

In determining the particular role of an assessor, some care must be taken that such an appointment must not constitute a delegation of judicial power. Lee J determined that, because of the nature of such an appointment, it could not be an impermissible delegation of judicial power.

Another issue relating to the use of an assessor is the procedural fairness of such an appointment – the assessor’s opinions are not tested in evidence or cross-examination. Such issues may simply be disposed of if the lengths and bounds of the operation of the assessors were explicitly determined. Another avenue to resolve such a concern may be for counsel, in consultation with the Court, to draft the questions to be answered. Counsel may address such answers in their submissions.

Beach J, writing extra-judicially, noted some examples where the appointment of an assessor may be appropriate:

  • delivering tutorials to the judge pretrial on relevant specialised topics;
  • explaining the expert report;
  • assisting the judge with any evidentiary objections in an unusually complex technical matter;
  • putting questions directly to counsel or witnesses at the hearing or suggesting questions for the judge to put to counsel or witnesses;
  • generally, acting as a discipline on the behaviour of expert witnesses in a concurrent evidence session who may otherwise perceive that they can confound the lawyers present with technical complexity without challenge; and
  • conferring with the judge after trial to assist the judge to get the technical concepts correct.

In particular circumstances, where the expert evidence canvasses a highly technical or specialised area, where the cost-benefit analysis weighs in favour, and where an appropriate candidate can be found, the appointment may provide for a more efficient hearing, judgement may be delivered sooner, and such a judgement may make more cogent and compelling factual findings.

The content of this article is intended to provide a general guide to the subject matter. Specific advice should be sought about your specific circumstances.

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