Discussion
35 In my opinion, relevant authority establishes that while (as reflected by the Federal Court Practice Note and like curial protocols) objectivity and independence are sought of expert witnesses, such qualities are not preconditions of competence, even in the case of expert witnesses. The sanction for failure to fulfil the obligations imposed by relevant authority and curial protocols is not the exclusion of the expert's evidence, but rather, the significant risk that it will fail to persuade.
36 In FGT Custodians Pty Ltd (formerly Feingold Partners Pty Ltd) v Fagenblat [2003] VSCA 33 ("FGT Custodians"), the Victorian Court of Appeal considered whether any legislation, relevant authorities, historical rules of evidence, court rules or protocols disqualified a witness from testifying as an expert witness by reason of bias or perceived bias.
37 In FGT Custodians, the appellant contended that a valuer (the brother-in-law of a party, whose sister allegedly stood to gain if that party succeeded in the litigation) was precluded from giving expert evidence. The appellant relied on Lord Wilberforce's dictum in Whitehouse v Jordan [1981] 1 WLR 246 at 256-257 that:
it [is] necessary that expert evidence presented to the Court should be, and should be seen to be, the independent product of the expert, uninfluenced as to form or content by the exigencies of litigation,
and like authorities.
38 Ormiston JA (with whom Chernov and Eames JJA agreed), in a scholarly exposition, stated (at [4]-[5]) that, properly analysed, given that the evidence was undoubtedly relevant, the sole issue was whether the witness was competent to give the expert evidence. His Honour cited Gleeson CJ's statement in Festa v The Queen (2001) 208 CLR 593 at 599 that:
If evidence is of some, albeit slight, probative value, then it is admissible unless some principle of exclusion comes into play to justify withholding it from [the Court's] consideration.
39 His Honour recognised that, as the objection was to the witness's expert evidence as a whole, it went to competence, rather than admissibility of particular aspects. The two questions relevant to the witness's competence were:
(a) whether he was qualified by training or experience to give expert evidence; and
(b) whether, because he was in breach of some other rule relating to the giving of this kind of evidence, he should be treated as disqualified from giving it.
40 Ormiston JA (at [5]) "firmly distinguished" the above matters from:
those matters which may go to impeach the reliability of a witness's testimony, namely those that are based on cross-examination or other evidence to show inadequate expertise or bias or interest by reason of conduct or other circumstances.
41 Ormiston JA stated that expert evidence was not and had never been excluded, or expert witnesses disqualified, by reason of an interest in the nature of perceived bias. His Honour concluded that in the case before him, the witness did not lack capacity due to his interest in the outcome, or apprehended bias, although as a matter of common sense, it was desirable that an expert witness be seen to be independent (at [29] to [30]).
42 His Honour observed that even the limited historical exclusions of spouses and persons with a direct legal interest in the outcome of litigation (as distinct from mere prejudice or bias arising from relationships, friendship or other motives) were much criticised by the beginning of the nineteenth century, and thereafter progressively abolished.
43 Ormiston JA reiterated at [12]:
I know of no principle stated as a principle of the common law which would exclude as incompetent the evidence of a person otherwise qualified to give expert testimony but who is said to be affected by interest or bias.
44 Ormiston JA observed that the concern frequently expressed about a lack of independence in expert witnesses had been addressed by devising court rules and protocols imposing obligations of independence. His Honour stated (at [15]) that such protocols, generally speaking, should not be treated as stating principles of the laws of evidence, but as admonitions to those who give expert evidence if they (and their clients) wish it be acted on.
45 Ormiston JA's analysis, in my opinion, applies with equal force to s 79 of the Evidence Act and the Federal Court Practice Note. It was adopted by Weinberg J in SmithKline Beecham (Australia) Pty Ltd v Chipman (2003) 131 FCR 500 at [32] to [37]. Thus, a lack (or perceived lack) of independence, or an interest in the outcome of litigation, including through a family relationship with, or even the status of, a party does not render any witness, including an expert (except, perhaps, as Ormiston JA observed, a court appointed expert) incompetent, and thereby exclude that person from giving evidence.
46 Protocols or judicial statements requiring independence in expert witnesses thus do not constitute a precondition of competence, but rather, a preferred practice.
47 A lack of objectivity combined with other circumstances may, in some cases, justify exclusion of an expert witness's evidence pursuant to s 135 of the Evidence Act.
48 In Pan Pharmaceuticals, the plaintiff company's liquidators filed voluminous expert reports out of time. The defendant sought to exclude the report of one expert witness under ss 79 and 135 of the Evidence Act on, inter alia, the ground that he lacked objectivity, as he had a long involvement with the liquidators, including advising the liquidators' solicitors on matters relevant to the claim, suggesting questions for further investigation and helping to draft the original statement of claim and responses to requests for particulars (at [154]). The witness's drafts were the subject of a claim for privilege, so the extent of his involvement could not be fully tested, yet he had relied on earlier drafts to prepare the expert report the liquidators sought to tender (at [154]). As the witness declined to reveal the substance of his numerous prior communications with the liquidators in helping to formulate their case against the respondent, Emmett J stated that "[i]t is well nigh impossible to test his credibility or reliability in circumstances where his role in the formulation of the case against [the defendant] is substantially unknown" (at [155]).
49 Emmett J concluded that (at [157]):
The prior involvement of Dr Clark in the preparation of the Liquidators' case against [the defendant] is not necessarily fatal to the admissibility of the Clark Report. However, in the light of Dr Clark's lack of independence and the insistence on professional privilege on the part of the Liquidators, it would be unfair to [the defendant] for Dr Clark's evidence to be before the Court. It cannot be properly tested. It should be afforded so little weight that its exclusion would not prejudice the Liquidators' case.
50 In Pan Pharmaceuticals, Emmett J described the report of another expert witness as a "series of answers to the highly specific and leading questions posed by the solicitors" for the party who sought to call the witness (at [107]), which took months to prepare and "was based on assumptions that took the Liquidators' legal team years to generate" (at [108]). The report was based only on the experience of the witness, rather than his particular education.
51 His Honour considered that, having regard to the argumentative and leading nature of the questions posed for the opinion, the relevant report was of such equivocal weight that any inconvenience or detriment from its rejection outweighed the inconvenience and unfairness involved to the opponent in preparing to answer it. His Honour therefore held that to the extent to which the report was admissible, it should be rejected under s 135 of the Evidence Act (at [127]).
52 In the present case, the defendants did not rely on s 135 of the Evidence Act and the circumstances were not comparable to those in Pan Pharmaceuticals. Generally speaking, however, lack of objectivity or deviation from the obligation of independence, whether exposed by cross-examination or other evidence, merely goes to impeach the credibility or reliability of the expert evidence in question.
53 The defendants submitted that some aspects of Professor Inyatullah's report were partisan and argumentative, contrary to the stricture that an expert witness should not act as an advocate. In Pan Pharmaceuticals, Emmett J stated (at [29]):
[I]t is not permissible for [an expert] witness to take over the role of advocate, although a witness having expertise in a particular discipline may have a legitimate role of advocacy in that the evidence given by the witness may include arguments as to the conclusions that can be drawn, and perhaps should be drawn, from the facts that the witness is asked to assume.
54 Nevertheless, as the plaintiffs submitted, expert witnesses are entitled to disagree with other experts, to criticise their assumptions, weaknesses or lacunae in their research and to expose defects in their reasoning. Robust dissent from or criticism of the assumptions, quality and extent of research and reasoning of other experts is a frequent and sometimes necessary feature of expert testimony. Opinion evidence which is merely argumentative or lacks any evident basis in the expertise of the witness, may, however, be the subject of discrete objection, or accorded reduced or no weight.