The essence of the good sense referred to in this context is reflected in the well- worn truism that opinions are like navels; everyone has one and, in themselves, they are essentially useless. Other anatomical variations may be heard.
Reflecting that general lack of utility, and the fact that it is the role of the court rather than any witness to draw inferences from primary facts in order to determine an ultimate fact in issue, the law of evidence parallels commonsense by generally rejecting as inadmissible the opinion of a witness about a factual matter on which there is no direct evidence (and universally rejecting the opinion of a witness about which case or which party should ultimately prevail).
There are some minor exceptions in relation to matters which are accepted as being able to be reliably inferred by any witness2. The primary exception, however, is that which permits experts to give, as evidence, their opinions about the conclusions which may be inferred from the facts proved or assumed before the court.
The rules of expert evidence are designed to ensure that opinions which fall within the “essentially useless” category do not affect the disposition of litigation. They are, of course, nothing new, and form part of the general legal knowledge of all practitioners. However, some recent experience suggests that their detail can be overlooked in the heat of battle, possibly to the significant detriment of a client against whom purported expert evidence is sought to be asserted by the opponent.
One particular aspect of those rules which, at least in my view, does not always receive the careful and critical consideration required on occasions when one is either faced with or proposes to call expert evidence is the “area of expertise” rule.
The rules generally
Subject to some minor qualifications in later judgements , the seminal contemporary summary of the requirements for admissibility of expert opinion evidence is that by Heydon JA, as he then was, in Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR 705. At 743-744, His Honour stated:-
“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.”
Area of expertise
This is the first of Heydon J’s elements. It represents the fundamental threshold for the admissibility of expert opinion, and poses the question as to:-.
“… whether the subject matter of an opinion forms part of a body of knowledge or experience which is sufficiently organised to be accepted as a reliable body of knowledge or experience, a special acquaintance with which by the witness would render his opinion of assistance to the court” 4.
In Clarke v Ryan (1960) 103 CLR 486, Menzies and Windeyer JJ required that there be “an organised branch of knowledge in which the witness is an expert”5. The learned author of Cross on Evidence (again, Justice Heydon) observes that “organised branches of knowledge are normally those in which those who are trained or experienced share generally accepted principles and techniques”6.
Also in Clarke, Dixon CJ required that the subject matter so far partake “of the nature of a science as to require a course of previous habit, or study, in order to the attainment of a knowledge of it”. Again, the learned author of Cross observes that “a ‘science’ is usually regarded as something turning on generally accepted principles”7.
This rule is related to, but nevertheless quite distinct from, the rule requiring the particular witness to demonstrate appropriate qualifications, training or experience in a relevant area of expertise. The horse must come before the cart.
Obviously, there will be many contexts in which the existence of the relevant area of expertise will be quite uncontroversial and not a matter requiring forensic enquiry by counsel. Nevertheless, in areas where the asserted expertise is not “mainstream”, the question can be overlooked, particularly when presented with a professionally prepared “expert report” replete with an impressive CV and a collection of apparently scientific or technical appendices which are said to support the witness’ analysis and conclusions.
The example which I offer may well be viewed as mundane or even trivial in terms of its subject matter, but it graphically demonstrates, at least in my view, how failure to apply the fundamentals of expert evidence can lead to a clearly wrong result, possibly accompanied by significant injustice.
The keeping of “pit bull terriers” as domestic pets is restricted generally by State laws8, and entirely prohibited by many local governments in their particular areas9. Under either legislative scheme, it is an offence to keep a dog contrary to the applicable provisions. More importantly for the ordinary pet owner, Councils which have taken the prohibition route generally have local laws which empower them, without having prosecuted, to seize and destroy a dog which they assert to be of a proscribed breed.
When these matters end up in court10, the ultimate question for the court is a question of fact as to whether the dog in question is of the prohibited breed or, at least, whether there exists probative evidence of that matter upon which the Council was entitled to act.
The Council, of course, does not know and cannot know the breed of dog in question as a fact, at least in the absence of an admission by the owner11. A number of local governments have sought to bridge this gap by developing their own breed identification process, and by presenting witnesses to the courts as experts in this field, and therefore qualified to give evidence of opinion as to the breed of the dog.
The methodology which these witnesses employee involves comparison of the physical appearance of the dog with descriptions of physical features in a document called a “breed standard”, assigning a score of zero to three against each of the descriptions in that document, and coming up with a final score where some number of points (typically 46 of the possible 66) leads to a conclusion that the dog is of the breed alleged.
These witnesses have been accepted by the Magistrates Court on at least one occasion, including glowing judicial endorsement of their expertise12. Anecdotally, there have been many similar outcomes.
The problem with all this is that, as revealed by the evidence in a subsequent case in which the matter was squarely raised13, the area of expertise which might be described as “breed identification by application of breed standards” appears to be non-existent. The evidence presented in that case, which was unchallenged by the Council except by bare contrary assertion, was that a “breed standard” is a show judging document describing the ideal qualities of a prize-winning specimen, intended to be used by judges and breeders only in a context where the dogs are already known to be pedigreed examples of the breed. The use of a breed standard for “breed identification” (where breed is unknown and in dispute) was completely rejected in evidence by the author of the standard (called for the owner, and never previously contacted by the Council), and was shown to be unsupported by any professional or technical literature, or any dog breeder, dog judge or other animal professional anywhere.
I should, importantly, point out that the case did not go to judgement on this issue as the Council withdrew and returned the animal to the owner after the completion of evidence but before judgement. The threshold “area of expertise question” was not required to be judicially determined. However, the evidence seems to be objectively compelling, to the point of being overwhelming, that the area of expertise upon which all of the purported expert evidence was based was entirely unrecognised anywhere as a “body of knowledge or experience” meeting the required test.
Accepting that to be the case, it is clear that an injustice has occurred as a result of failure to properly apply the rules of expert evidence in earlier cases in which the evidence has been accepted. In case any reader thinks that “injustice” is too strong in the context of an issue about public safety, all of the cases of which I have direct knowledge concerned ordinary family pets, acquired from friends or acquaintances as backyard cross-breeds of unknown origin, none of which had ever displayed the slightest hint of dangerous or aggressive behaviour. It was all about what the Council thought they looked like. The subject matter may be of minimal money value, but the tears of the owners and their children were real enough.
No criticism is made of anybody appearing for the owners in those earlier matters, as the writer knows nothing about the extent to which counsel, in particular, had an opportunity to fully consider the matter prior to trial, or the extent to which individual owners would have had the financial resources to properly investigate the technical issues in any event. Self-evidently, at least from the owner’s perspective, these cases were not major commercial litigation with a budget to match.
Whether the much better resourced local governments had a responsibility to more carefully investigate these matters in terms of their own evidence, having regard to their “model litigant” responsibilities as a government agency, is, perhaps, a question for another time.
The point for present purposes is to highlight the importance of never assuming (except where the matter is well settled and clearly uncontroversial) that an area of expertise exists merely because the witness (or a government agency) says it does, or merely because the witness has been “accepted” as an expert in previous cases. As long ago as 1960, Clarke v Ryan (supra) illustrated how a purported expert witness who is not in fact entitled to testify can nevertheless carve out a long and lucrative career in that capacity unless the right questions are asked by opposing counsel.
The dog cases to which I have referred, while obviously conducted in a much less rarefied judicial forum, and with much less at stake (at least objectively, though the families would disagree) confirm that the lessons from that decision remain just as important today, perhaps even more so given that litigation in some jurisdictions (such as the Land Court and Planning and Environment Court) depends almost entirely on the acceptance or rejection of expert evidence15.
In short, it cannot be assumed that self-appointed expert is an extinct species. The area of expertise rule, while unimportant for the many well-settled areas of expertise encountered day to day, remains an essential part of the armoury to guard against the introduction of purported evidence which in fact lacks any probative value at all.
Stephen Fynes-Clinton
- See Lipovac v Hamilton Holdings Pty Ltd (unreported, ACT Supreme Court, 13 September 1996) per Higgins J at p 102
- Such as identification of persons, apparent age, and the bodily plight or emotional state of a person: see Frecketon & Selby, Expert Evidence, para [7.10]
- His Honour’s judgment was revisited by the New South Wales Court of Appeal on 20 May 2005 in Australian Securities and Investments Commission v Rich [2005] NSWCA 122. Spiegleman CJ (IPP and Giles JJA agreeing), explained that it was sufficient if an expert identifies and asserts the facts upon which his or her opinion is based (without having to disclose other facts known to the expert which could have been relied upon but which he or she says were not relied upon), but otherwise endorsed and applied the principles identified by Heydon JA. Special leave to appeal from that decision was refused by the High Court: [2005] HCA Trans 416.
- R v Bonython (1984) 38 SASR 45 at 46—47. See also in HG v R (1997) 141 CLR 411, at 432 and Velevski v R (2002) 76 ALJR 402, at 416, both per Gaudron J.
- at 501—2 and 508.
- Cross on Evidence, 7th Australian Edition, 2004, para [29055].
- Ibid.
- Local Government Act 1993, chapter 17A.
- Individual Councils can make their own local laws which override the State regime in this regard — LGA, s 1193D.
- Either by way of prosecution, which appears to be very rare, and more commonly by way of an administrative appeal to the Magistrates Court (where a local law so provides) or by way of proceedings under the Judicial Review Act 1991.
- Or the unlikely occurrence of a Council witness having been present at the mating of its parents!
- Maroske v Logan City Council, Magistrates Court, Beenleigh, No. 7195 of 2004, decision given on 22.07.2005.
- Da Fre v Logan City Council, Magistrates Court, Beenleigh, No. 5440 of 2005 The evidence has been made publicly available at http://www.dafrevlogancc.bigpondhosting.com.
- The ultimate disposition was that the owner’s appeal was allowed, and the Council ordered to pay the owner’s costs.
- Even in the ordinary civil courts, the conduct of any substantial litigation without an attempt to introduce expert evidence on some issue or other seems to be the exception rather than the rule.
