In order to be admissible under s 79, three conditions must be satisfied:
(a) the person must have a specialised knowledge;
(b) that specialised knowledge must be based on their training, study or experience; and
(c) the opinion must be wholly or substantially based on that specialised knowledge.
33 In my view, the evidence of Mr Murphy in these paragraphs is opinion evidence. He is seeking to provide evidence as to his expectations, his estimate of costs and possible ways in which the claims of the group members might be litigated, if at all, if the Court ordered that this proceeding no longer continue as a representative proceeding. Consequently, to be admissible it must fall within the exception contained in s 79 of the Evidence Act.
34 Counsel for Aristocrat relied on the well-known statements of Heydon JA in Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR 705 ('Makita'). According to his Honour, for expert evidence to be useful it was necessary for it to comply with 'the prime duty of experts in giving opinion evidence'; that is, to furnish the trier of fact with criteria enabling evaluation of the validity of the expert's conclusions: see Makita at [59]. After reviewing the common law and statutory requirements, Heydon JA stated at [85]:
'In short, if evidence tendered as expert opinion evidence is to be admissible, it must be agreed or demonstrated that there is a field of "specialised knowledge"; there must be an identified aspect of that field in which the witness demonstrates that by reason of specified training, study or experience, the witness has become an expert; the opinion proffered must be "wholly or substantially based on the witness's expert knowledge"; so far as the opinion is based on facts "observed" by the expert, they must be identified and admissibly proved by the expert, and so far as the opinion is based on "assumed" or "accepted" facts, they must be identified and proved in some other way; it must be established that the facts on which the opinion is based form a proper foundation for it; and the opinion of an expert requires demonstration or examination of the scientific or other intellectual basis of the conclusions reached: that is, the expert's evidence must explain how the field of "specialised knowledge" in which the witness is expert by reason of "training, study or experience", and on which the opinion is "wholly or substantially based", applies to the facts assumed or observed so as to produce the opinion propounded. If all these matters are not made explicit, it is not possible to be sure whether the opinion is based wholly or substantially on the expert's specialised knowledge. If the court cannot be sure of that, the evidence is strictly speaking not admissible, and, so far as it is admissible, of diminished weight. And an attempt to make the basis of the opinion explicit may reveal that it is not based on specialised expert knowledge, but, to use Gleeson CJ's characterisation of the evidence in HG v The Queen (1999) 197 CLR 414, on "a combination of speculation, inference, personal and second-hand views as to the credibility of the complainant, and a process of reasoning which went well beyond the field of expertise" (at [41]).'
(Emphasis added)
35 His Honour continued at [87]-[88] stating that:
'There is no doubt about Professor Morton's authority, experience, qualifications and skill. It is also the case that Professor Morton's report is quite lengthy and detailed. But, given that the court is not obliged to take the opinion of an expert as conclusive even though no other expert is called to contradict it, can it be said that Professor Morton's report goes beyond a series of oracular pronouncements? Does it usurp the function of the trier of fact? More vitally, did it furnish the trial judge with the necessary scientific criteria for testing the accuracy of its conclusions? Did it enable him to form his own independent judgment by applying the criteria furnished to the facts proved? Was it intelligible, convincing and tested? Did it go beyond a bar ipse dixit? Did it contain within itself materials which could have convinced the trial judge of its fundamental soundness?
It is significant that the trial judge himself did not identify any scientific criteria within the report for testing the accuracy of its conclusions. The trial judge summarised Professor Morton's evidence ([125]-[134]) and accepted his conclusions ([203]-[204]). But he did not analyse Professor Morton's conclusions. Perhaps he did not feel the need to do so, in view of the fact that no expert was called in opposition to Professor Morton, and in view of the fact that the cross-examination of Professor Morton was not lengthy. However, it remains the case that the trial judge did no more than accept the conclusions as they were stated.'
36 In respect of the statements of Heydon JA quoted above at [34], Branson J in Sydneywide Distributors Pty Ltd v Red Bull Australia Pty Ltd (2002) 55 IPR 354 ('Red Bull') stated at [7] that:
'The approach of Heydon JA…is, as it seems to me, to be understood as a counsel of perfection. As a reading of his Honour's reason for judgment as a whole reveals, his Honour recognised that in the context of an actual trial, the issue of the admissibility of evidence tendered as expert opinion evidence may not be able to be addressed in the way outlined…'
37 Her Honour continued at [9] in stating:
'…[A[ny ruling on the admissibility of evidence is ordinarily required to be made by the trial judge during the course of the trial rather than at its conclusion. In this regard the trial judge does not have the advantage enjoyed by a court of appeal of having before it the whole of the evidence adduced at trial. The trial judge's ruling will be based on the evidence and other relevant material, which may include assurance given by counsel, which are before the judge at the time that the ruling is required to be made. It is no longer common practice for a witness from whom expert opinion evidence is intended to be adduced to be examined by opposing counsel on the voire dire. This may be because, perhaps regrettably, the practice has come to be regarded as of little practical value where the judge, and not a jury, is the trier of facts. As a result the judge is likely to be asked to rule on the admissibility of the affidavit, report or oral evidence of a witness put forward as an expert before the witness is subject to any questioning by opposing counsel. For this reason, it may prove to be the case that evidence ruled admissible as expert opinion will later be found by the trial judge to be without weight for reasons that, strictly speaking, might be thought to go to the issue of admissibility (eg that the witness's opinion is expressed with respect to a matter outside his or her area of expertise or is not wholly or substantially based on that expertise).'
(Emphasis added)
38 At [16]-[17] her Honour stated:
'Further, the requirement that an expert opinion be wholly or substantially based on the witness's specialised knowledge is not, in my view, intended to require a trial judge to give meticulous consideration, before ruling on the admissibility of the evidence of the opinion, to whether the facts on which the opinion is based form a proper (in the sense of logically or scientifically or intellectually proper) base for the opinion. Were the position otherwise the smooth running of trials involving expert evidence could be expected to be interrupted by the need to explore in detail, in the context of admissibility, matters more properly considered at the end of the trial in the context of the weight to be attributed to the evidence. It is sufficient for admissibility, in my view, that the trial judge is satisfied on the balance of probabilities on the evidence and other material then before the judge that the expert has drawn his or her opinion from known or assumed facts by reference wholly or substantially to his or her specialised knowledge. In many cases the relevant evidence and other material that will be before the judge at the time that the judge is required to rule on admissibility will extend little, if at all, beyond the purported expert's affidavit or report or, where only oral evidence is intended to be adduced, the earlier oral evidence of the witness and the form of the question to which objection has been taken. In the Federal Court, the usual practice of requiring expert evidence to be reduced to writing, together with the Guidelines for Expert Witnesses referred to in [13] above, will generally ensure that there is sufficient material before the judge to enable the judge to form a view, on the balance of probabilities, (albeit, in the context of the trial as a whole, a provisional view) as to whether an opinion is wholly or substantially based on the witness's specialised knowledge. In most other jurisdictions there are now comparable equivalent rules or guidelines.
Evidence later adduced, most likely in cross‑examination, might reveal that an opinion proffered in an affidavit or report is not wholly or substantially based on the witness's specialised knowledge, or that the expert made an error (whether of logic, science or otherwise) in the process of reaching his or her opinion. While that evidence might be relevant to admissibility in a hypothetical sense, it would not, of itself, demonstrate error in the earlier ruling that the affidavit or report be received in evidence. The correctness of that ruling is to be judged by reference to the relevant evidence and other material before the judge at the time of the ruling. The evidence might, however, be of crucial importance with respect to the weight to be accorded the opinion at the end of the day.'
(Emphasis added)
39 In Red Bull, Weinberg and Dowsett JJ also discussed the approach advocated by Heydon JA in Makita. Their Honours stated at [87]:
'The use of the phrase "strictly speaking" in the last sentence should not be overlooked. It may well be correct to say that such evidence is not strictly admissible unless it is shown to have all of the qualities discussed by Heydon JA. However many of those qualities involve questions of degree, requiring the exercise of judgment. For this reason it would be very rare indeed for a court at first instance to reach a decision as to whether tendered expert evidence satisfied all of his Honour's requirements before receiving it as evidence in the proceedings. More commonly, once the witness's claim to expertise is made out and the relevance and admissibility of opinion evidence demonstrated, such evidence is received. The various qualities described by Heydon JA are then assessed in the course of determining the weight to be given to the evidence. There will be cases in which it would be technically correct to rule, at the end of the trial, that the evidence in question was not admissible because it lacked one or other of those qualities, but there would be little utility in so doing. It would probably lead to further difficulties in the appellate process.'
(Emphasis added)
40 In Neowarra v Western Australia (No 1) (2003) 134 FCR 208 ('Neowarra'), Sundberg J stated at [22]-[23] that:
'The "basis rule" does not feature in s 79. The Australian Law Reform Commission explained why. That the legislation does not include any common law "basis" requirement is now established by the cases. See Quick v Stoland Pty Ltd (1998) 87 FCR 371 at 373‑374 and Sydneywide Distributors Pty Ltd v Red Bull Australia Pty Ltd [2002] FCAFC 157 at [10]. See also Guide Dog Owners' & Friends' Association Inc v Guide Dog Association of New South Wales (1998) 154 ALR 527 at 531. Cf Makita…
While the legislation does not incorporate a "basis rule", an expert should nevertheless differentiate between the facts on which the opinion is based and the opinion in question, so that it is possible for the court to determine whether the opinion is wholly or substantially based on the expert's specialised knowledge which in turn is based on training, study or experience. See HG v The Queen at [39] per Gleeson CJ. In Ocean Marine Mutual Insurance Association (Europe) OV v Jetopay Pty Ltd [2000] FCA 1463 at [23] the Full Court said that a report on which an opinion is recorded should express the reasoning of its author in a way that shows that the opinion is based on particular specialised knowledge.'
41 After discussing the emphasised portion of the statement of Heydon JA quoted at [34] above, his Honour stated at [24]-[25]:
'That seems to me, with respect, to be restoring the basis rule. The reason his Honour gave for requiring this and the other presently immaterial requirements is that "if all these matters are not made explicit, it is not possible to be sure whether the opinion is based wholly or substantially on the expert's specialised knowledge". While that may be so with respect to other requirements, the expert's exposure of the facts upon which the opinion is based is sufficient to enable the relevant enquiry to be carried out. That enquiry is not dependent on proof of the existence of those facts.
HG v The Queen does not support the supposed requirement. After stating that an expert should differentiate between the assumed facts upon which the opinion is based and the opinion itself, Gleeson CJ said at [39]:
"Argument in this Court proceeded upon the basis that it was possible to identify from Mr McCombie's written report some facts which he either observed or accepted, and which could be distinguished from his expressions of expert opinion. Even so, the provisions of s 79 will often have the practical effect of emphasising the need for attention to requirements of form. By directing attention to whether an opinion is wholly or substantially based on specialised knowledge based on training, study or experience, the section requires that the opinion is presented in a form which makes it possible to answer that question."
His Honour does not thereby require, as a condition of admissibility, that the assumed facts on which the opinion is based are established by the evidence. If at the end of the evidence they are not established, the weight to be accorded the opinion will be reduced, perhaps to nil. But that is not a matter of admissibility.'
42 See also, Sampi v State of Western Australia [2005] FCA 777 per French J at [798]-[802]; Jango v Northern Territory of Australia (No. 4) (2004) 214 ALR 608 per Sackville J at [19]; and Seven Network (Operations) Ltd v Media Entertainment and Arts Alliance [2003] FCA 1366 per Gyles J at [6].
43 To the extent that the decisions of this Court referred to above disclose an approach different to that of Heydon J in Makita, in particular the decision of Sundberg J in Neowarra and comments of the Full Court in Red Bull, I must respectfully adopt those of this Court unless I am of the view that they are plainly wrong. I should note, however, that I have exercised particular caution in examining Mr Murphy's evidence in this context as, at least in part, it goes to whether or not the proceeding is an effective and efficient way to deal with the claims of the group members. While s 80(a) of the Evidence Act provides that opinion evidence is not inadmissible merely because it is about a fact in issue or an ultimate issue, the Court should 'exercise particular scrutiny when experts move close to the ultimate issue, lest they arrogate expertise outside their field or express views unsupported by disclose and contestable assumptions': R v GK (2001) 53 NSWLR 317 per Mason P (with whom Dowd J agreed generally) at 326-327. See also, Adler v Australian Securities and Investments Commission (2003) 46 ACSR 504 per Giles JA (with whom Mason P and Beazley JA agreed) at [622].
44 In my view, Mr Murphy can be said to have a specialised knowledge in respect of class action legal proceedings and representative proceedings in particular. This is based on his experience in this area. I accept Mr Bathurst's submission that the evidence contained in these paragraphs is at a high level of generality. This is necessarily so because of the nature of the evidence Mr Murphy seeks to give. In my opinion, the basis of the opinions was, for present purposes, sufficiently disclosed for the evidence to be admissible as demonstrating that the opinions are based wholly or substantially on Mr Murphy's specialised knowledge. The evidence is relevant insofar as it provides an opinion as to a comparison between the relative costs of different types of proceedings, a factor relevant to the exercise of the termination power contained in s 33N of the Act. Whether or not the assumptions and the evidentiary basis disclosed are supportable will ultimately turn on consideration by the Court of whether those are valid assumptions to make in determining the weight to be given to this evidence. However, in my view the evidence was admissible under s 79 of the Evidence Act. As a consequence, I ruled at the hearing that the evidence was admissible and Mr Murphy was subjected to cross-examination.
45 As indicated above, a large part of Mr Murphy's first affidavit was accepted only as submissions. I shall address those submissions in due course. In so far as his affidavit evidence was admissible, it dealt with the cost to all parties of large and complex commercial litigation and the additional costs that would be incurred if the MBC criterion was not included in the group definition. Mr Murphy also gave evidence of his experience of the effect of 'opt out' procedures and the problems arising from the failure of people who had no interest in the proceeding to take the positive step of opting out of the proceeding. He referred to the fact that ILF would only fund the proceeding if all who might benefit from the funding entered into funding agreements.
46 Mr Murphy also deposed that, like Mr Walker, he was not aware of any person who had expressed an interest in joining the group but objected to entering into the retainer and funding agreements. Mr Murphy also included estimates as to the future costs of the proceeding. On cross-examination it became apparent that these estimates were materially flawed in that they greatly overestimated the costs that would be involved in continuing the representative proceeding without the MBC criterion in the group definition and the cost of pursuing the claims other than under Part IVA of the Act. Despite this, however, I am satisfied from Mr Murphy's evidence that the financial and efficiency advantages of the MBC criterion are significant.