An expert must be highly qualified in their field or discipline and in the particular area in dispute, capable of articulating their views, and, most of all, an expert must be independent.

This is the first of a two-part refresher article on the nature of expert evidence and legal professional privilege. In this article we consider what expert evidence is, who is an expert and the procedural requirements that must be observed when using an expert witness in legal proceedings in NSW.

Expert evidence may become one of the most important aspects of any contested legal proceedings. To maximise the prospects of success it is essential to understand the role of the expert and procedural requirements.

What is expert evidence and who is an expert?

Expert evidence is evidence of a person's opinion where that person has particular knowledge or experience of an issue that is outside an ordinary person's knowledge or experience. Expertise can be acquired through either training, study or practical experience.

When do you need an expert?

An expert is needed to establish a fact or the likelihood of a fact where it is subject to the special knowledge of the expert. For example, an expert may be asked to give evidence on the cause of a fire and the likelihood of when that fire started. If there is more than one possible explanation, the expert's role is to give the Court guidance as to which explanation should be preferred on the balance of probabilities.

It is also worthwhile considering whether an expert is required at all. If direct evidence can be found on the relevant issue, an expert will potentially only add to the cost and length of the proceedings.

Where do you find an expert?

Experts can be found by the following means:

  • contacting the professional or trade association for the particular discipline;
  • requesting references/recommendations of persons in the field or discipline;
  • approaching teaching institutions in which the discipline is taught;
  • approaching colleagues who have experience in working on similar cases;
  • researching similar cases involving experts; and
  • using commercial organisations such as Unisearch, Access-UTS and Expert Experts.

How do you choose an expert?

An expert must be credible. In other words, an expert must be highly qualified in their field or discipline and in the particular area in dispute, capable of articulating their views, and, most of all, an expert must be independent.

When choosing an expert, it is important to ascertain their reputation and standing in their field or discipline and, if possible, how they have previously performed in the court room.

Briefing an expert

All relevant facts must be given to the expert, not just the client's version of events. If an expert is not briefed properly with all the relevant facts, their evidence may be rejected.

For the opinions of the expert to have any value, the evidence must clearly identify the facts and/or assumptions upon which the opinion is based. No weight will be given to the evidence if the underlying factual basis is not made out.

The Uniform Civil Procedure Rules 2005 (NSW) require experts to be provided with a copy of the Expert Witness Code of Conduct either at the time the expert is engaged or as soon as practical thereafter. An expert's report will not be admissible unless the expert has acknowledged in the report that a copy of the Code of Conduct was received and the expert agrees to be bound by it.

Under the Code of Conduct, an expert witness:

  • has an overriding duty to assist the court impartially on matters relevant to the expert's expertise;
  • has a paramount duty to the court, not to the party who retained them; and
  • is not an advocate for a party.

Care must be taken when briefing an expert to ensure that their independence is not, and cannot be perceived to be, compromised.

Expert reports

Expert reports must meet certain requirements so that the evidence is given due weight by the Court. An expert's report must include:

  • the expert's qualifications as an expert on the relevant issue;
  • the facts, and assumptions of fact, on which the expert's opinions are based;
  • reasons for each opinion expressed;
  • whether a particular issue falls outside the expert's field of expertise;
  • any literature or materials utilised in support of the opinions reached;
  • examinations, tests or investigations on which the expert has relied and the qualifications of those that carried them out; and
  • for lengthy or complex reports, a brief summary of the report.

Furthermore, an expert must state in the report whether the expert believes their report may be incomplete or inaccurate without some qualification and if the expert's opinion is not a concluded opinion because of insufficient research, insufficient data or any other reason. A supplementary report must also be provided if the expert changes their opinion on a material matter after providing the expert report.

The Court may also order experts to confer and provide it with a joint report setting out those matters agreed and not agreed at conference.

What is the role of a legal adviser?

The opinions expressed by an expert should be the opinions of the expert, not opinions influenced by the legal advisers or the client for whom the expert is retained. It is improper for a legal adviser to coach an expert witness or suggest an answer that an expert witness should give.

Legal advisers may contribute to the process in the following areas:

  • identifying the issues in dispute to which expert evidence may be relevant;
  • identifying an expert or experts qualified to express opinions upon those issues;
  • framing the issues in respect of which the expert is required to express an opinion;
  • specifying the assumptions of fact that the expert is to make;
  • supplementing those assumptions of fact with primary factual material for the expert to consider;
  • working with the expert in the drafting of the report to draw out any assumed knowledge on the subject matter of the report; and
  • ensuring that the evidence is relevant, admissible and has persuasive value.