Karpik v Carnival plc

Introduction 1 An issue has arisen with regard to the admissibility of certain learned articles published in scientific journals during the course of the trial of this class action. The issue has arisen after all witnesses have completed their evidence and been excused, and there is no intention to apply to recall any witness. 2 There is a substantial volume of medical-related expert evidence in the trial. Amongst other issues, the evidence is directed at questions such as the incubation period of the SARS-CoV-2 virus, the prevalence of asymptomatic infections of the virus, the modes of transmission of the virus including what the state of scientific knowledge was in that regard in early March 2020, the extent of asymptomatic and pre-symptomatic transmission of the virus, the contagiousness of the virus including with reference to the basic reproductive number (R0) and the secondary attack rate (SAR), and the significance of a negative SARS-CoV-2 PCR test followed some time later by serology (blood) tests positive for SARS-CoV-2 antibodies. As might be expected, the expert reports are replete with references to learned articles published in scientific journals on which the expert opinions are based. 3 It is uncontroversial that those articles are admissible in evidence. As it was explained in Bodney v Bennell [2008] FCAFC 63; 167 FCR 84 at [93] by Finn, Sundberg and Mansfield JJ, there is nothing in the Evidence Act 1995 (Cth) that displaces the body of common law that provides that experts are entitled to rely upon reputable articles, publications and material produced by others in the area in which they have expertise as a basis for their opinions. Experts may not only base their opinions on such sources, but may give evidence of fact which is based on them. They may do this although the data on which they base their opinion or evidence of fact will usually be hearsay information, in the sense that they rely for such data not on their own knowledge but on the knowledge of someone else. That statement was approved in Dasreef Pty Ltd v Hawchar [2011] HCA 21; 243 CLR 588 at [110] by Heydon J. 4 Significant in the body of law referred to is Borowski v Quayle [1966] VR 382 at 386-387 where Gowans J quoted the following passage from Wigmore on Evidence (3rd ed) Vol 2, pp 784-785 para 665(b): The data of every science are enormous in scope and variety. No one professional man can know from personal observation more than a minute fraction of the data which he must every day treat as working truths. Hence a reliance on the reported data of fellow-scientists, learned by perusing their reports in books and journals. The law must and does accept this kind of knowledge from scientific men. On the one hand, a mere layman, who comes to court and alleges a fact which he has learned only by reading a medical or a mathematical book, cannot be heard. But, on the other hand, to reject a professional physician or mathematician because the fact or some facts to which he testifies are known to him only upon the authority of others would be to ignore the accepted methods of professional work and to insist on finical and impossible standards. Yet it is not easy to express in usable form that element of professional competency which distinguishes the latter case from the former. In general, the considerations which define the latter are (a) a professional experience, giving the witness a knowledge of the trustworthy authorities and the proper source of information, (b) an extent of personal observation on the general subject, enabling him to estimate the general plausibility, or probability of soundness, of the views expressed, and (c) the impossibility of obtaining information on the particular technical detail except through reported data in part or entirely. 5 It can thus be seen that expert reliance on such learned publications is not excluded by the rule against hearsay (s 59) or the opinion rule (s 76). 6 There are two categories of learned publications the admissibility of which the parties dispute. Common to both categories is that the articles are not referred to in any of the expert reports that have been tendered, confirmed on oath or affirmation and that have been the subject of cross-examination. In the first category are two articles sought to be tendered by the applicant which were put to one of the respondents' expert witnesses, Professor Catherine Bennett, in cross-examination. The four articles in the second category, which are also sought to be tendered by the applicant, were not referred to in the evidence of any of the experts. 7 The objection taken to both categories of articles is that admission of them would be contrary to the opinion rule in Pt 3.3 of the Evidence Act read together with Div 23.2 of the Federal Court Rules 2011, which deals with parties' expert witnesses and expert reports, and the Court's Expert Evidence Practice Note (GPN-EXPT). The short point that is made is that even if it were to be accepted that the opinions expressed in the articles were wholly or substantially based on the authors' specialised knowledge based on their training, study or experience (as required by s 79(1) of the Evidence Act), the requirements of the Court's rules and practice with regard to the admission and testing of expert reports have not been satisfied in relation to the articles.

Category two articles 8 It is convenient to deal first with the category two articles, ie, articles that have not been the subject of any witness evidence. 9 The applicant has not referred to any authority which supports the admission of learned articles in category two. The applicant refers to R v Patel (No 6) [2013] QSC 64, particularly at [10]-[11], where Fryberg J admitted into evidence a learned article published in a medical journal which had been the subject of cross-examination. The judgment is accordingly authority relevant to category one, but not to category two. Fryberg J referred to R v Karger [2001] SASC 64; 83 SASR 1, but that was also a case where scientific articles were admitted as having been "accepted as forming part of the body of knowledge of the relevant scientific community", which was established by a witness, and they formed the basis of the opinions of witnesses in the case. The articles were not sought to be used as evidence independent of any witness. 10 Reference was also made to QIW Retailers Ltd & Attorney-General (Cth) v Davids Holdings Pty Ltd (No 3) [1993] FCA 288; 42 FCR 255, particularly at 275, where Spender J explained his Honour's reference in the reasons for judgment to the learned articles of economists on the question of market definition in a competition case on the basis of them having been referred to in "the elaborate arguments that were presented to the court both in the course of submissions and in the course of the evidence of some of the economic experts who were called in the proceedings". Although it is not entirely clear, it seems that that was also a category one case - ie, that all of the articles had been referred to in the evidence of some of the experts. 11 That understanding is supported by Spender J's reference to PQ v Australian Red Cross Society [1992] 1 VR 19 and Concha v Murrieta (1889) 40 Ch D 543. In the former, McGarvie J at 34-35 admitted "information in authoritative scientific publications" on which an expert witness relied as a basis for a portion of their evidence as forming part of the testimony of the witness. In the latter, Cotton LJ at 550, with whom Lindley LJ agreed, and Lopes LJ at 554, held that where an expert witness on foreign law refers to passages in the Code of the relevant foreign law, the court can receive the Code itself in evidence and have regard to it to consider its proper meaning. Lopes LJ went a step further to say that the legal document to which the witness refers is to be taken as part of the testimony of the witness. (In Australia, this question in relation to proof of foreign law is now governed by ss 174-175 of the Evidence Act.) 12 In any event, in QIW Retailers there was apparently no objection taken to the admissibility of the articles or to the use to which they were put. The judgment is therefore no authority for the proposition that the category two articles are admissible. 13 In Commissioner for Government Transport v Adamcik [1961] HCA 43; 106 CLR 292 the issue before the jury had been whether the deceased's leukaemia from which he died and which was discovered 12 days after he had been injured by being knocked from the footboard of the tramcar of which he was the conductor had been caused by the accident. Dr Haines, for the plaintiff, the deceased's widow, had given evidence that he considered that it was probable that the leukaemia was the result of the accident. Two physicians, one of whom was Sir William Morrow, said that there was no connection between the accident and the leukaemia, although Sir William agreed in cross-examination that there were suggestions in medical literature that some cases of leukaemia had been the result of trauma, but he said that in his view that had been generally discarded in literature published in the preceding 20 years. Also, in an article produced to him it was said that all the cases of leukaemia that had followed trauma had been of a different variety of leukaemia to that suffered by the deceased. Windeyer J (with whom Kitto J agreed) explained as follows (at 307-308): Statements in text-books and in articles in medical journals are not, in themselves, evidence, unless they be accepted or approved by competent witnesses in the box. The content of some medical literature was brought out in the cross-examination of Sir William Morrow, without, however, his assenting to it as correct. Ordinarily a jury could properly consider this only to test the evidence of the witness, not as itself evidence of fact. But, in this case, they could, for another purpose, legitimately have regard to what was read from books. It had been suggested to Doctor Haines in cross-examination and, no doubt, later urged upon the jury, as it was to us, that no support at all for his view was to be found anywhere in any medical writings. In answer to this suggestion, the jury could notice what was put forward as supporting his view and consider whether it did so. 14 There is nothing in that passage that supports the view that learned articles can be used independently of any witness. Indeed, use of the articles in that fashion would amount to use contrary to Wigmore's guidance - it would be equivalent to a layperson coming to court alleging a fact which they have learned only by reading a medical or a mathematical book. They cannot be heard. 15 It follows from the above authorities that learned articles that are not the subject of expert opinion do not satisfy the gateway of admissibility in s 79(1) of the Evidence Act. They are therefore excluded by s 76 and inadmissible. They are also excluded by s 59 as amounting to hearsay evidence. They do not qualify for the "business records" exception in s 69 because they are not the internal records of any business but rather the product of the business, whether that is of the profession of the author or the business of the publisher: Roach v Page (No 15) [2003] NSWSC 939 at [5]-[8]; ACCC v Air New Zealand Limited (No 5) [2012] FCA 1479; 301 ALR 352 at [11]-[15]. 16 I also accept the submission on behalf of the respondents that the Court's rules and practice with regard to expert evidence amount to a code of procedural fairness; it would be procedurally unfair to the respondents to admit the articles that were not put to any expert witness or adopted by any expert witness, nor the subject of discussion in the expert conclaves, and in respect of which the respondents have had no opportunity to cross-examine the authors of the articles to test their methodology, conclusions and opinions or to adduce the evidence of their own experts in contradiction of the articles. To allow the category two articles to be tendered in those circumstances would consequently be unfairly prejudicial to the respondents within the meaning of s 135(a) of the Evidence Act and I would also exclude them on that basis.

Category one articles 17 I turn now to the category one articles, ie, articles that were put to Professor Bennett in cross-examination. 18 In respect of the one article (numbered A657 and titled "Close proximity risk assessment for SARS-CoV-2 infection"), Professor Bennett said that she was not familiar with it (T768:40). That is hardly surprising when one considers that it was written by engineers with regard to particle dynamics whereas Professor Bennett's expertise is in epidemiology. That notwithstanding, Professor Bennett went on to engage with propositions put to her said to be supported by the article, including expressing reservations with regard to what can be drawn from the authors' study. I do not understand Professor Bennett to have adopted the views expressed in the article, which in any event would appear to be outside her expertise. Nevertheless, in order to properly understand her evidence it is necessary to have regard to the article - she was referred to parts of the article which were not read onto the record and which in any event may require context to be properly understood. 19 In respect of the other article in this category (numbered A610 and titled "Shorter incubation period is associated with severe disease progression in patients with COVID-19"), Professor Bennett said that she was familiar with the article and had last considered it the previous day or two (T691:46). Professor Bennett once again engaged with propositions put to her said to be supported by the article, including expressing reservations with regard to the authors' study. As with the other article, I do not understand Professor Bennett to have adopted the views expressed in the article. Nevertheless, for the same reasons, in order to properly understand her evidence it is necessary to have regard to the article. 20 In the circumstances, the articles in category one should be admitted under s 77 of the Evidence Act. That section provides that the opinion rule does not apply to evidence of an opinion that is admitted because it is relevant for a purpose other than proof of the existence of a fact about the existence of which the opinion was expressed. The purpose here being to properly understand the witness's evidence. 21 The applicant submits that on that basis, once admitted under s 77, the articles are admitted for all purposes. In response to that, the respondents submit that the articles could then be used for an opinion purpose which would be unfairly prejudicial to them - for the reasons dealt with above in relation to the category two articles - and that the admission of the articles should therefore be limited under s 136. The postulated limitation is that the articles be admitted for the purpose of understanding the oral evidence but not to independently prove any fact or opinion stated in them. 22 It was said in Seven Network Ltd v News Ltd (No 8) [2005] FCA 1348; 224 ALR 317 at [21] by Sackville J that considerable care should be exercised before s 136 is invoked to limit the use of evidence on the ground that its use might be unfairly prejudicial to a party in a procedural sense. That was because the policy apparently underlying provisions such as ss 60 and 77 should not be undercut by the making of orders under s 136 as a matter of course, particularly where a judge, rather than a jury, is the trier of fact, since the danger of unfairness to a party might be expected to be mitigated by the judge attributing less weight to material that cannot adequately be tested. 23 With that caution in mind, I am not satisfied that it would be unfairly prejudicial to the respondents for the second of the two articles referred to above (ie, A610) to be admitted for all purposes and for any prejudice to be dealt with as a matter of weight. That is because the subject matter of the article is within the expertise of the witness to whom it was put and its subject matter is covered by the expert evidence given by a number of witnesses. The Court will be well-placed to consider anything that the article has to say relative to what has been said by the witnesses and to give the article appropriate weight in the circumstances. 24 However, the first article referred to above (ie, A657) is in a different category. That is because it deals with an area of expertise not possessed by any of the many expert witnesses in the case. In those circumstances there is no other evidence against which to compare, or weigh, the opinions and conclusions expressed in the article. The Court is therefore in an invidious position with regard to trying to assess the weight to give to those opinions and conclusions. For that reason, taken together with the absence of any opportunity for the respondents the test or challenge those opinions and conclusions, I am satisfied that to not limit the use to which the article can be put under s 136 would be unfairly prejudicial to the respondents. Such a limitation is necessary and does not undercut the policy underlying s 77.

Disposition 25 In the circumstances, my rulings on the evidence covered by these reasons are as follows: (1) The articles numbered A613, A670, A706 and A725 in the applicant's tender list are not admitted. (2) The article numbered A610 in the applicant's tender list is admitted under s 77 of the Evidence Act. (3) The article numbered A657 in the applicant's tender list is admitted, subject to limitation under s 136 of the Evidence Act, for the purpose of understanding the oral evidence but not to independently prove any fact or opinion stated in the article. I certify that the preceding twenty-five (25) numbered paragraphs are a true copy of the Reasons for Ruling of the Honourable Justice Stewart.