EXPERT EVIDENCE IN COPYRIGHT CASES – CONCURRENT
EXPERT EVIDENCE AND THE “HOT TUB”

The Hon Justice Steven Rares*

1.	Australian courts and agencies have been acknowledged as having the most experience with the “hot tub” method in which experts give their evidence concurrently.  This is not a parochial boast, but recently appeared in the American Journal Anti-trust.
2.	The purpose of this paper is to explain, first, a little bit of history about expert evidence, secondly, the purposes and technique of concurrent evidence, and thirdly, perhaps concurrently, the technique’s virtues.  The genesis of my participation here, as my co-presenter Kate Haddock informed me, was my use of concurrent expert accounting evidence in a copyright infringement case aptly named Australasian Performing Right Association Ltd v Monster Communications Pty Ltd.  There, two experts gave concurrent evidence sitting on the bench with me, because the courtroom was not able to be arranged to sit them in the well of the Court.
3.	Despite my enthusiasm for concurrent evidence, both experts in that case expressly said that they could not explain a very curious and critical change in the recording of data by Monster that occurred shortly after midnight on a day in May 2005.  The effect of that change, if accepted, may have substantially reduced the infringement damages for which Monster was liable.  Despite the experts agreeing that they were unable to explain the reason for the mystery, their evidence was helpful.  This was because it converted what might otherwise have been an expert matter into a simple question of fact.  I was able to make findings based on the absence of explanation for the change by Monster in circumstances where that company might have been expected to know what had caused the contentious change.  But this may advance the discussion too far for now.
4.	This paper, despite its title, only looks at the topic of concurrent evidence generically.  As will appear, the technique is of general application.   I have seen it used to deal with topics as diverse as accounting, quantity surveying, fire protection requirements, wildlife paths, metallurgy, naval architecture, expert navigation of Panamax size (230m) container ships in a gale, mechanical engineering, the appropriate flooring for elephant enclosures in zoos and the mating of those mammals.  Even in copyright, it is not difficult to imagine the utility of concurrent evidence where expert questions of similarity, economics or copying arise.  And like all forensic tools, things can go wrong, such as asking one question too many.  
A Short Historical Excursion
5.	Courts have struggled for a long time with the consequences of the adversarial system in the use by each party of an expert whose evidence, at least in chief, favours that party.  Prof Wigmore suggested that the remedy lay in “… removing this partisan feature:  i.e. by bringing the expert witness into court free from any committal to either party”.  There was a fear in judges that this object is not easy to achieve.  Sir George Jessel MR observed in a patent case that sometimes the Court had appointed its own expert under an inherent power to do so.  He lamented:
“It is very difficult to do so in cases of this kind.  First of all the Court has to find out an unbiased expert.  That is very difficult.”

6.	Earlier he had discussed the way parties searched for experts to find one or more who would give evidence in support of the party’s case, leaving the rest as discards, about whom the Court would know nothing.  He said that he had been counsel in a case where his solicitor had consulted 68 experts before finding one who supported their client’s case;  hence his mistrust of the system of “opposing” experts.
7.	Expert evidence has been a provocative topic, both among lawyers and experts.  In the twelfth edition of Best on Evidence published in 1922 the learned authors, who included Sidney L Phipson, said:
“… there can be no doubt that testimony is daily received in our courts as
‘scientific evidence’ to which it is almost profanation to apply the term;  as being revolting to common-sense, and inconsistent with the commonest honesty on the part of those by whom it is given.”

8.	On the other hand, Prof Wigmore evoked a vision that giving expert evidence was akin to coming to a graveyard or indeed the calvary, saying:
“Professional men of honorable instincts and high scientific standards began to look upon the witness box as a golgotha, and to disclaim all respect for the law’s method of investigation.  By any standard of efficiency, the orthodox method registers itself as a failure, in cases where the slightest pressure is put upon it.”

9.	No doubt many have had the experience of seeing an eminent and reputable expert in their field subjected to a cross-examination calculated to evoke the very response which Prof Wigmore noted.  Such persons come away from the forensic experience justifiably scarred and disdainful of it as a process for eliciting intelligent and appropriate examination of expert opinion.  They can be so discouraged by their forensic experiences that they no longer wish to be involved in assisting courts.
10.	Experts have long been used in court cases.  Sometimes the expert is a person appointed by the Court to assist it.  In admiralty matters, judges in England have sat since the sixteenth century with (usually two) elder brethren of Trinity House to assist and advise them in assessing who was at fault in cases concerning marine casualties.  The elder brethren were usually skilled, experienced master mariners one set of whom advised the trial judge, another set advised, the Court of Appeal and yet another set, the House of Lords.  Although Sir Winston Churchill also was made an elder brother, as a result of his having been First Lord of the Admiralty, I doubt he assisted in any proceedings in the Probate, Admiralty and Divorce Division.  More recently, Justice Heerey, appointed an expert as a court assessor to sit with him in a patent case under the provisions of s 217 of the Patents Act 1990 (Cth).  The parties paid for the cost.  
11.	Lord Sumner once cautioned about courts deferring to assessors’ opinions.  They, like experts, have a place that he appositely described:
“Authority for the proposition that assessors only give advice and that judges need not take it, but must in any case settle the decision and bear the responsibility, is both copious and old. It is for them to believe or to disbelieve the witnesses, and to find the facts, which they give to their assessors and which must be accepted by them. If they entertain an opinion contrary to the advice given, they are entitled and even bound, though at the risk of seeming presumptuous, to give effect to their own view.”

12.	By leaving the questioning entirely in the control of counsel, who may or may not fully understand the subject matter, an expert can be made to look as bad as the engineer and fire assessor cross-examined by Norman Birkett KC on the cause of a fire in a motor vehicle.  Birkett’s first question to the expert was the memorable line:  “What is the coefficient of the expansion of brass?”.  The “expert” was destroyed by his inability to even understand the question let alone respond to Birkett in an appropriate way.  Some criticisms have been advanced subsequently of the line of questioning, including Birkett’s failure to identify the inherent assumption in the question as to the proportions of copper and zinc making up the particular specimen of brass to which the question was supposed to relate.  Perhaps a true expert may have been able to respond immediately that he needed that information before being able to answer the question, in which case Birkett may have been thrown back on his resources or been shown up himself.
13.	Concurrent evidence is a means of eliciting expert evidence with more input and assistance from the experts themselves in lieu of their, perhaps unfairly, perceived role as being inherently, even if not consciously, biased to the case of the party calling them.  This is not my perception, but has developed as Jessel MR once described through a distrust of expert evidence:
	“… not only because it is universally contradictory, and the mode of its selection makes it necessarily contradictory, but because I know of the way in which it is obtained. I am sorry to say the result is that the Court does not get that assistance from the experts which, if they were unbiassed and fairly chosen, it would have a right to expect.”

14.	The task for a judge, or a jury, in choosing between the views of persons eminent in their fields is no easy one.  Often in my experience at the Bar, the real dispute between experts did not lie in their conclusions at all.  Rather, it was that they had proceeded on different assumptions.  Because they were briefed by the particular litigant paying them, they were not asked to opine as to whether, if they accepted the other experts’ assumptions, they would come to the same conclusion as the other expert.  Instead, the experts debated the assumptions.  This was largely a sterile exercise for them, since they did not have knowledge of the primary facts.
15.	One feature of the process of conventional expert evidence is that the cross-examiner often will spend a great deal of time asking about the assumptions on which the opposing expert has based his or her conclusions.  Then there will be a lengthy time interval until the defendant’s or respondent’s expert gets into the witness box and the context in which the second expert’s evidence is given will be different and, perhaps, significantly so, to that earlier.
16.	In the Federal Court of Australia, and in other tribunals presided over by Federal Court judges, concurrent evidence is also used.  Indeed, Lockhart J, when President of the Trade Practices Tribunal, was credited with being instrumental in introducing the technique to Australian jurisprudence.  One of the first uses of the “hot tub” in court proceedings in Australia was by Justice Rogers in an insurance case in 1985.
17.	Concurrent expert evidence is used extensively in the Land and Environment Court of New South Wales, principally as a result of the enthusiasm of the Hon Justice McClellan, when Chief Judge of that Court.  His Honour’s enthusiasm spilled over into the Common Law Division of the Supreme Court of New South Wales.  In addition the Administrative Appeals Tribunal uses the technique robustly and its President, Justice Downes, has written extensively on the topic.
Concurrent Evidence in Practice
18.	Initially, and my own experience is to this effect, uninitiated counsel are highly suspicious of concurrent evidence.  That suspicion evaporates once they participate.  Why is this so?  It is because of the efficiency and discipline which the process brings to bear.
19.	The way concurrent evidence generally works, though individual judges or tribunals may have their own variants, is that after each expert has prepared his or her report, there is an order that they confer together, without lawyers, to prepare a joint report on the matters about which they agree and those on which they disagree, giving short reasons as to why they disagree.  Often this process will identify that the experts agree on everything that each has said in his or her reports, on the basis that the opposing expert accepts the assumptions which the other has used.  Thus, the role of the expert evidence is finished, and the question resolves into one of dry fact proved by lay witnesses or other evidence, as was my experience in the Monster case.  On most other occasions, the range of difference between the experts, which had been apparently vast if one put their two reports side by side, reduces to a narrow point or points of principle.
20.	At the conclusion of both parties’ lay evidence, the experts are called to give evidence together in their respective fields of expertise.  It is important to set up the court room so that the experts (there can be many on occasion) can all sit together with convenient access to their materials for their ease of reference.  One microphone is then made available for all of the experts.
21.	The judge explains to the experts the procedure that will be followed and that the nature of the process is different to their traditional perception or experience of giving expert evidence.  First, each expert will be asked to identify and explain the principal issues, as they see them, in their own words.  After that each can comment on the other’s exposition.  Each may ask then, or afterwards, questions of the other about what has been said or left unsaid.  Next, counsel is invited to identify the topics upon which they will cross-examine.  Each of the topics is then addressed in turn.  Again, if need be, the experts comment on the issue and then counsel, in the order they choose, begin questioning the experts.  If counsel’s question receives an unfavourable answer, or one counsel does not fully understand it, he or she can turn to their expert and ask what that expert says about the other’s answer.
22.	This has two benefits.  First, it reduces the chance of the first expert obfuscating in an answer.  Secondly, it stops counsel going after red herrings because of a suspicion that his or her own lack of understanding is due to the expert fudging.  In other words, because each expert knows his or her colleague can expose any inappropriate answer immediately, and also can reinforce an appropriate one, the evidence generally proceeds directly to the critical, and genuinely held, points of difference.  Sometimes these differences will be profound and, at other times, the experts will agree that they are disagreeing about their emphasis but the point is not relevant to resolving their real dispute.
23.	The experts are free to ask each other questions or to supplement the other’s answers after they are given.  The only rule being that the expert who has the microphone has the floor.  Generally the experts co-operate with one another and freely and respectfully exchange their views.  Often one will see them arriving at a consensus which becomes clear through the process.
24.	A great advantage of concurrent evidence is that all the experts on the topic are together in the witness box at the one time, answering the one question on the same basis.  Everyone is together on the same page.  This is a world away from a traditional cross-examination of each expert in the various parties’ cases, sometimes happening days, if not weeks, apart with a raft of other evidence having interposed.  The judge is able, just as the lawyers, to understand the issue.  The experts feel capable of explaining the matters to the judge and putting their points of view in a way in which they feel free to use their knowledge and experience.  Justice McClellan described the process as:
“… essentially a discussion chaired by the judge in which the various experts, the parties, advocates and the judge engage in an endeavour to identify the issues and arrive where possible at a common resolution of them. In relation to the issues where agreement is not possible a structured discussion, with the judge as chairperson, allows the experts to give their opinions without constraint by the advocates in a forum which enables them to respond directly to each other.  The judge is not confined to the opinion of one advisor but has the benefit of multiple advisors who are rigorously examined in a public forum.”

25.	In a recent trial that I heard, two metallurgists had to explain their differing theories on the way in which a pipeline fractured in Port Phillip Bay.  The surviving piece of pipe, weighing many kilos, was in the well of the Court on a table.  As they, the lawyers and I all stood around it, each of the experts took me to the individual spots on the pipe from different positions and angles from which they had drawn their conclusions as to the way in which it fractured.  And, as one gave his view, the other commented on it in an orderly and respectful way.  Each of them was able to explain and to explore with the other fully the way in which their various fracture hypotheses were put.   The only interruptions were made by me seeking to describe some of the matters which the experts had pointed out, but not described orally, so that there would be a transcript record of their evidence.  After this, they proceeded to a more conventional “hot tub” in the witness box.
26.	Another significant benefit of the process is generally a substantial saving of court time and costs.  In my first experience of the technique, a valuation case in the Land and Environment Court before the then Chief Judge, Justice McClellan, there were many experts in various fields.  The evidence in their reports amounted to over one metre in height.  Yet most of the expert evidence, apart from that of the four valuation experts was, ultimately, the subject of joint reports on which all points were agreed.  In the remaining few reports where there was disagreement, the area of dispute was narrowed to one, two or three small points of principle that were dealt with in concurrent evidence in blocks of between 10 and 30 minutes.  The two valuers for the applicant asserted that the value of the easement was between $20 million and $30 million.  The two for the resuming authority argued that it was worth in the order of $1 million or a little more.  Their concurrent evidence concluded in a day and a quarter.
27.	In such a dispute, in a conventional trial, an individual valuer would have been cross-examined probably for over a day, and four would have been likely to take well over six days.  There would have been extensive attacks on the selections of comparable properties, the varying assumptions of the land’s development potential and the like.  And, in that case the only reason the valuation evidence went longer than a day, was that one of the experts changed his evidence because of newly agreed expert evidence from another field that affected the costs of development.  That change required further cross-examination.
28.	The Judicial Commission of New South Wales and the Australian Institute of Judicial Administration jointly produced a DVD of that experience entitled “Concurrent Evidence – New Methods with Experts”.  It is the largest selling publication of the Judicial Commission.  It provides a good example of how the technique works.  Modesty prevents me from identifying the other counsel whose participation with Bernie Coles QC, my opponent, in the re-enactment, directly from the transcript, is partly featured on the DVD.
29.	Justice McClellan has observed, as have I, that the process removes the ordinary tension that exists in a conventional trial where expert evidence is led.  The experts feel that they are able to explain their views, and if need be, defend them, in an intellectual discussion with their fellow expert or experts.  Each of the experts presence with the other or others induces them to be precise and accurate.  Generally, they are less argumentative than in a normal confrontational cross-examination process.  Each knows that the other expert is able to understand exactly what he or she is saying and, so cannot rely on the technique so criticised in the passage I quoted earlier from Best on Evidence.
Criticisms of Concurrent Evidence
30.	Concurrent evidence, like the curate’s egg, is only good in parts.  The decision whether to proceed or continue with taking evidence concurrently may be influenced by the need to ensure fairness in the trial process.  Some critics, including the prominent economist, Henry Ergas, and Justice Davies formerly of the Court of Appeal of the Supreme Court of Queensland, have expressed concern that “hot tubs” may result in the more persuasive, confident or assertive expert winning the judge’s mind, by, in effect, overshadowing or overwhelming the other’s.
31.	Mr Ergas suggested that the “hot tub” was a response to a perceived problem that experts, in giving complex economic evidence, would “dumb down” their analysis into accounts that were little more than analogies to their underlying reasoning so as to enable the lawyers, or decision-makers, to understand the concepts.  He feared that this would result in economists, not trained in or familiar with the forensic analysis involved in cross-examination, rarely approaching the “hot tub” in a structured and systematic way.  He thought that “hot tubs” were especially at risk of being dominated by participants who were more confident or assertive, traits which were unrelated to the merits of the analyses being presented.  He also considered that time constraints could often mean that the discussion remained at a relatively superficial level, thus further limiting its value.
32.	Justice Davies echoed similar criticism.  He expressed a concern that the judge could be left with two opposed, but comparatively convincing, opinions by equally well qualified experts neither of whom had been shaken in the process.  He suggested that the “hot tub” protracted, rather than shortened proceedings and that it was too cumbersome, expensive and “too adversarial”.  He was obviously suspicious of the likely integrity of the whole process.  He speculated like, Sir George Jessel MR more than a century before, that the parties’ solicitors or counsel would audition the best expert to give evidence in court (as if that would be a new consideration).  Justice Davies also argued that the parties’ lawyers would see the experts in conference before giving evidence and suggest how best to answer questions in a way consistent with the respective expert’s stated opinion and the party’s case.
33.	Those criticisms have not been validated in practice.  Contrary, to those spectres, experts generally take the various courts’ expert codes of conduct very seriously.  After all, in general they value their reputations and integrity.  But more fundamentally, the joint report process often reveals that one party’s case on a critical point will succeed or fail.  This is because the experts are able to understand, through professional exchanges, what each has said and on what assumptions.  The frequency of experts in joint reports agreeing on critical issues shows that the experts retain their independence and cut through the parties’ different instructions to each, to reach the core question which they then answer.
34.	Another legitimate concern is that “hot tubs” are controlled idiosyncratically by the individual judge or tribunal.  Indeed, the structure of the concurrent evidence process may vary from case to case with the same judge or tribunal member as it can, from topic to topic during the one “hot tub” session.
35.	However, the same may be said of a conventional cross-examination.  Horses need to suit courses.  Not every set of expert witnesses on every issue will proceed with a topic in the same way.  That may be because the issue in dispute between the parties, or one set of experts, or on one topic between experts, may be of a character that requires a particular approach, while other issues require different approaches.  My experience has been that where it is necessary to engage in a rigorous, structured cross-examination of an aspect of the expert opinions, it is possible to do so in a conventional way.  Conventional and effective cross-examination as to credit is also, equally, possible.  One example is shown on the DVD to which I referred earlier.
Overall Experience of Concurrent Evidence
36.	Concurrent evidence, in general, greatly reduces the hearing time.  It efficiently and effectively identifies the issues.  By the judge allowing each expert to explain himself or herself, both at the beginning and at the end of the whole process, it is possible to allow them to feel they have done justice to themselves even where a cross-examination has occurred during the “hot tub” in a conventional way.  Where, as sometimes happens, the expert does not feel he or she had been treated fairly in cross-examination, they can then explain what they think their point was.  Whether the judge or tribunal accepts the explanation is a different question.  Even at this final stage the basis of what the expert is then saying may be revealed to be self-serving as opposed to giving a true explanation. And if the parties’ lawyers consider that something arises which, in fairness, they wish to pursue out of any final explanation, they can then have a further opportunity to test it by cross-examination.
37.	No system is perfect.  There are many flaws in each of our systems for obtaining evidence in court, but like Sir Winston Churchill’s analysis of democracy, it may be the worst possible system, but it is the best that anyone has yet invented.  At the end of the process one or more of the experts on occasion has volunteered that he or she have found this to be a much more satisfactory way of giving evidence than in a conventional cross-examination.  Gary Edmond criticised such responses by suggesting that they should be viewed with caution given the power relationship between the judge or tribunal member and the witnesses appearing before them.  I agree that caution is appropriate but not determinative.
38.	Experts participating in the two cases I had at the bar using concurrent evidence, expressed satisfaction to me, in my then role, that they had found this to be a better experience than that in conventional trials.  There does not appear to be much written adverse criticism by experts who have participated in the process of concurrent evidence suggesting that any felt they were not able to get their points across, were overawed, overborne or outperformed by another “hot tubber”.  Again, one cannot draw too much from this since people rarely wish to explain publicly why they felt inadequate in a previous performance.  Nor am I aware of anecdotal discussion of actual instances of these suggested problems occurring.
Conclusion
39.	Litigation is an expensive, lengthy, stressful, and not always exact, means of undertaking a decision-making process.  At the end of the day the judge or jury must select whether they are satisfied or persuaded that one of the competing versions is to be preferred or accepted.  Like other witnesses, experts will leave impressions on judges based on demeanour, including their apparent persuasiveness, whether giving evidence alone or in a “hot tub”.
40.	Nonetheless, at least where judges are the tribunals of fact, the modern approach of courts was summarised by Gleeson CJ, Gummow and Kirby JJ in Fox v Percy.  It is that courts are cautious about the danger of drawing conclusions too readily concerning truthfulness and reliability solely or mainly from the appearance of witnesses.  They pointed out that in recent years scientific research has cast doubt on the ability of judges or anyone else to tell truth from falsehood accurately on the basis of such appearances.  They said that considerations of this kind have encouraged judges both at a trial and on appeal to limit their reliance on the appearance of witnesses and to reason to their conclusions, as far as possible, on the basis of contemporary materials, objectively established facts and the apparent logic of events.  Their Honours cited an incisive observation of Atkin LJ:
“… I think that an ounce of intrinsic merit or demerit in the evidence, that is to say, the value of the comparison of evidence with known facts, is worth pounds of demeanour.”

41.	Because the experts have conferred and produced joint reports before going into the “hot tub”, the field of dispute is generally narrowed.  Not all cases will suit the process.  It may be that in patent cases, where the whole case revolves around conflicts within fields of expertise, concurrent evidence is not likely to assist a judge.  Heerey J’s expedient of an assessor may prove a better alternative.  But concurrent evidence allows advocates to focus on the critical differences, with the assistance of their respective experts in the box, and, at the same time to hammer home the strengths of their own, and the inadequacies in the other, expert’s reasoning processes.  In the end, concurrent evidence is generally likely to produce more ounces of merit which will be worth more to a judge than pounds of charisma or demeanour.