Expert evidence can play a crucial role in litigation. An expert witness is a person with specialised knowledge based on their training, study or experience. They are able to give opinion evidence about matters that are within their particular area of expertise. When determining whether to brief an expert in proceedings, it is critical to consider whether an expert is necessary at all, the type of expert needed, and whether the evidence will ultimately assist the court.
Practitioners may need to consult more than one expert, or engage an expert to form an opinion on their client’s prospects of successful litigation.
The case law concerning expert evidence highlights the key risks involved when briefing an expert. Key issues that might emerge include the independence of an expert, the instructions that may be given to an expert and whether an expert’s opinion is ultimately within the scope of their evidence. Ultimately, issues such as those may determine whether the expert opinion is admissible as evidence. Other considerations include whether a legal practitioner’s notes of a conference with an expert may be subject to a claim for legal professional privilege, and the role a legal practitioner should play in the preparation of an expert report.
Expert Evidence
The evidence of an expert must comply with the Evidence Act 1995 (NSW) (Evidence Act) and the Uniform Civil Procedure Rules 2005 (NSW) (UCPR).
The admissibility of expert evidence is an exception to the general rule that witnesses may not give evidence of opinion, but only of facts: s 76 of the Evidence Act 1995 (NSW).
Expert opinion is admissible as evidence only if the opinion is given by a person who has specialised knowledge based on the person’s training, study, or experience, and the opinion is wholly or substantially based on that specialised knowledge: s 79 of the Evidence Act 1995 (NSW).
The role of the expert is not to decide the issues in dispute, or to advocate the position of a party but to act independently to assist the court in reaching a decision as the ultimate trier of facts.
In civil proceedings, even if an expert’s opinion is considered relevant under s 55 of the Evidence Act, it may still be excluded by the operation of s 135 (which provides the court with general discretion to limit the use of evidence) or by s 136 (which allows the Court to limit the use of evidence if there is a danger that a particular use of the evidence might be (a) unfairly prejudicial to a party, or (b) misleading or confusing).
In NSW Courts subject to the UCPR, most proceedings require the parties to obtain a direction from the Court before adducing expert evidence.
The operation of s 79 of the Evidence Act
The prevailing case on the obligations and responsibilities of expert witnesses is set out in Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR 705 (Makita) where Heydon JA considered the operation of s 79 and laid out the following criteria at [85] for the admissibility of expert evidence:
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firstly, there must be a field of “specialised knowledge”;
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there must be an identified aspect of that field in which the witness demonstrated that by reason of specified training, study, or experience, the witness has become an expert;
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the opinion must be “wholly or substantially based on that specialised knowledge”;
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So far as the opinion is based on facts:
(a) they must be identified and admissibly proved by the expert, and
(b) so far as the opinion is based on “assumed” or “accepted” facts, they must be identified and proved in some other way;
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the observed or assumed facts must form a proper foundation for the opinion expressed; and
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the opinion requires demonstration or examination of how the scientific or other intellectual basis of the conclusions were reached: that is, how does the specialised knowledge on which the opinion is based, apply to the facts assumed or observed so as to produce the opinion.
We explore this criteria in further detail below.
The requirement of “specialised knowledge”
In the recent case of R v Flemming [2023] NSWSC 560, the court was required to consider whether the opinion provided by an expert could properly be considered “specialised knowledge” under s 79 of the Evidence Act in order to be admissible as evidence.
This case involved criminal proceedings, with the accused facing trial for allegedly engaging in terrorist offences. The critical issue was whether the accused’s conduct could be considered a “terrorist act” within the meaning of s 101.1(1) of the Criminal Code (Cth).
The prosecution sought to adduce evidence from a professor called as an expert in a subject referred to as “right wing extremism”. The professor was asked to explain “concepts relevant to right wing extremism” and to analyse documents written by the accused to give an opinion as to his ideology.
While the professor’s evidence was understood to be relevant, the court considered that the study of “right wing extremism” was a nascent area of study, and accordingly, an area so recent that it has not yet had time to develop a substantial body of knowledge.
The court held that the “specialised knowledge” upon which the witness based her opinions “appears to be more akin to that which might be possessed by a well-read individual who is informed with respect to contemporary world politics. However, being widely read upon recent right-wing terrorist events does not necessarily equate to expertise in the context of s 79 and a criminal trial concerning particular issues.”
As such, the court considered that the conclusions drawn by the professor were, at best, “informed speculation” and were therefore not admissible as evidence under s 79.
Furthermore, the court found there were reasons for the exclusion of the evidence pursuant to s 137 of the Evidence Act. Firstly, some of the material relied upon by the professor was not relevant to the proceedings and were, themselves, impermissibly prejudicial. Secondly, the professors refusal to speak to the accused, or discuss her evidence or subject of expertise with counsel and her instructing solicitor, did not accord with the conduct expected of an an independent expert, and had seriously hindered the ability of the accused’s counsel to assess the admissibility of the evidence and accordingly to respond.
For those reasons, even if the professor’s evidence had been admissible pursuant to s 79, it was ruled that it would have been excluded pursuant to s 137.
The reasoning of the expert’s opinion
Acceptance by the court of the opinion of an expert is closely tied to understanding the reasoning process by which the opinion was reached.
As described above, Makita makes it clear that an expert must provide the basis for each opinion so that it is clear to the court what specialised knowledge and what particular facts each opinion is based on in order to evaluate the validity of the expert’s conclusions. The court must see the connection between the opinion expressed and the specialised knowledge.
In Makita, Heydon JA stated at [59] that it is “a prime duty of experts in giving opinion evidence: to furnish the trier of fact with criteria enabling evaluation of the validity of the expert’s conclusions”.
In Dasreef Pty Ltd v Hawchar [2011] 243 CLR 588 (Dasreef), Heydon J stated further at [129] that: “It is necessary to avoid the insidious risk that the trier of fact will simply accept the opinion without careful evaluation of the steps by which it was reached, and hence the evidence must state the criteria necessary to enable the trier of fact to evaluate that the expert’s conclusions are valid. … admissibility does depend on the reasons being stated.”
If an expert does not offer an explanation, provide the reasoning for their opinion, or demonstrate the process by which the opinion was reached, there is no way for the court to evaluate the basis of that opinion.
The Duties and Responsibilities of an Expert
The case of Makita offers a succinct summary of the duties and responsibilities of an expert witness in civil proceedings. Citing National Justice Compania Naviera SA v Prudential Assurance Co Ltd (The ‘Ikarian Reefer’) [1993] 2 Lloyd’s Rep 68, Heyden J usefully summarises at paragraph [49] those duties and responsibilities as follows:
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Expert evidence must, and should be seen to be, the independent product of the expert uninfluenced as to form and content by the exigencies of litigation;
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An expert witness should provide independent assistance to the court by way of objective unbiased opinion and should never assume the role of an advocate;
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An expert witness should state the facts or assumptions upon which the opinion is based, and should not omit to consider material facts that could detract from the concluded opinion;
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The expert should make it clear when a particular question or issue falls outside their expertise;
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If an expert’s opinion is not properly researched because the expert considers there is insufficient data, this must be stated with an indication that the opinion is no more than a provisional one, and in cases where an expert witness could not assert that the report prepare contained the truth, the whole truth and nothing but the truth without some qualification, then that qualification should be stated in the report;
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If, after the exchange of expert reports, an expert witness changes their view on a material matter having read the export report adduced by the other side, or for any other reason, such change of view should be communicated (through legal representatives) to the other side without delay and when appropriate to the Court; and
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Where expert evidence refers to materials such as photographs, plans, calculations, analysis, measurements, and survey reports, such documents must be provided to the opposite party at the same time as the exchange of the reports.
The duties and responsibilities of expert witnesses are now repeated and expanded upon in the Expert Code of Conduct, which is set out in Schedule 7 of the UCPR. An expert must, as part of their report, acknowledge that they have read the Code of Conduct and agree to be bound by it. If the expert fails to do so, the report will not be admissible as evidence.
Client legal privilege
Legal professional privilege aims to protect the confidentiality of communications between clients and their lawyers and promote the free and frank exchange of information between them.
The law concerning privilege around materials relating to an expert witness is not always clear. As such, it is prudent to assume that once you want to rely on an expert report, very little will be protected under legal privilege.
Several client legal privilege issues can arise when dealing with expert witnesses. Often an expert will express preliminary views before the issues have been confined and before the provision of detailed information/documentation. If so, there may be a risk that any preliminary views expressed in writing could be subject to discovery. If there is an inconsistency with materials expressing the expert’s preliminary view and an expert’s final report, that inconsistency may be used in cross-examination to undermine the expert’s opinion.
Whether such documents are properly the subject of a claim for legal professional privilege will ultimately fall upon the scope of legal professional privilege; being either “legal advice privilege” which protects confidential communications between a lawyer and a client which came into being for the dominant purpose of providing legal advice, or “litigation privilege”, being confidential communications which came into being for the dominant purpose of the client being provided with professional legal services relation to a proceeding or anticipated proceeding.
As expert reports are typically prepared in the context of litigation, litigation privilege will most often be the basis for which privilege is claimed; that is, was the document produced for the “dominant purpose” of litigation.
In Enkelmann & Ors v Stewart & Anor [2023] QCA 155 (Enkelmann), the court found that privilege included the right to prevent the disclosure of confidential communications between a client’s lawyer and third parties when made for the client’s benefit.
The court also confirmed that privilege can protect from disclosure of confidential material that records the work the lawyer carried out for the client’s benefit.
In Enkelmann, the Queensland Court of Appeal held that “a solicitor’s file note of a conference with an expert, noting or reporting an opinion expressed by the expert at the conference, is not a document consisting of a “statement or report of an expert” within the meaning of rule 212(2) of the Uniform Civil Procedure Rules 1999 (Qld) (UCPR).”
The notes were made to provide confidential legal advice about the pending litigation. Therefore, the solicitor’s file note of a conference with an expert was subject to legal privilege.
The Court was also asked to consider whether the appellant’s conduct during the trial waived the privilege.
A waiver can be express or implied. When a court needs to decide about an implied waiver, it will consider whether the party’s conduct is inconsistent with maintaining confidentiality, which the privilege is intended to protect.
In this case, the appellant did not object or raise legal professional privilege when the expert was cross-examined about the conference where the file notes were taken. The court held that even if the appellants did not subjectively intend to waive their privilege by allowing the expert to give evidence of the conference, the appellants acted inconsistently with maintaining the privilege.
In light of the appellant’s conduct, the communications were no longer confidential, and the court held the appellant couldn’t later maintain a claim of legal professional privilege. As such, the file notes had to be disclosed.
Is the expert’s draft report privileged?
Whether a draft report produced by an expert in the context of litigation can be subject to a claim of privilege is a complex issue that must be considered on a case-by-case basis. Again, the answer will depend on the dominant purpose for which the draft was prepared.
If the draft was prepared for the expert’s own purposes, for example, as part of their thought process or as part of the evidence the expert intends to give in the final report, it will not attract privilege (Australian Securities and Investments Commission v Southcorp Limited [2003] FCA 804 at [21]. This is because the document has been generated unilaterally by the expert witness, and is not in the nature of a communication.
However, if the report was generated for the purposes of communicating the report to the legal advisor with the dominant purpose of being furnished for comment or advice by the legal advisor for the purposes of the litigation, it will generally attract legal privilege (New Cap Reinsurance Corporation Ltd (In Liq) and 1 Or v Renaissance Reinsurance Ltd [2007] NSWSC 258 at [34]).
If the draft report is shared with the opposing party, the privilege is waived.
Ethical issues to consider
Ethical issues may arise when briefing experts for litigation.
Can a solicitor be involved in drafting the report?
The expert should draft their report. It is generally not appropriate for the legal advisor to draft an expert report on behalf of the expert.
This issue was recently addressed by the Federal Court of Australia in NEW AIM PTY LTD (ACN 115 804 432) v LEUNG and Others [2023] FCAFC 67 (New Aim). The case provides clear guidelines of best practice when engaging expert witnesses.
New Aim involved an appeal against a finding that the extent of the solicitor’s involvement in drafting the relevant expert report was impermissible. The trial court was not satisfied that the opinions expressed in the report truly represented the expert’s honest and independent opinions.
The appeal was allowed, and the court made the following comments regarding a solicitor’s involvement in drafting the report.
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It is not unusual for a solicitor to draft factual evidence from a statement or material provided by a witness. Although it is less common to do so with expert witnesses, there are reasons why this might occur. (It might be necessary to record the expert’s evidence for physical, language, or resource reasons.)
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Where this does occur, the legal practitioner must not suggest what the expert’s evidence should be, and the report must be drafted from what the expert has communicated to the legal practitioner.
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A legal practitioner may disclose their involvement and all correspondence relating to the preparation of the expert report in the report itself. However, there is no legal obligation to do so. Whether or not there is an ethical obligation depends on the circumstances.
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The court also commented on the letter of instruction to the expert and highlighted the process should be transparent. Therefore, the material placed before the court should clarify what has been provided to the expert and the questions the expert was asked to address.
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Although there is no legal obligation to disclose all correspondence relating to the preparation of the report, it might be desirable, and again, whether there is an ethical obligation to do so depends on the circumstances.
Conclusion
When briefing an expert, solicitors must consider both legal and ethical obligations not only when sourcing an expert but throughout the process of delivery by the expert of their written report. An experienced litigator is best placed to provide guidance as to whether expert evidence will be required and if so, the process of obtaining that expert evidence.
