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Beach, Jonathan --- "The use of assessors in class actions" [2015] PrecedentAULA 47; (2015) 129 Precedent 15


By The Hon Justice Jonathan Beach

Class actions, as compared with individual proceedings, have a different dimension in their use of scientific and other technical evidence. Because of the economies of scale in dealing with an action that aggregates a large number of individual claims with significant aggregate sums, it becomes economically viable to use new forensic techniques and science than might otherwise be justified for a proceeding involving only an individual claim.

For example, in shareholder class actions, linear regression analysis is used to measure the share price inflation caused by the nondisclosure of material information. In cartel class actions, multiple linear regression analysis is used to determine whether price collusion has been put into effect. In product liability class actions involving personal injury claims, considerable investment may be made in epidemiology as well as evidence demonstrating an actual or potential biological pathway between the alleged causative agent and its effect. In common law class actions such as the recent Victorian bushfires class actions, science may be specifically developed to deal with novel technical questions for which there has been little prior analysis by researchers. In such class actions, highly technical evidence may be adduced, which would not normally be adduced in an individual action because of the disproportionate cost involved. How such evidence is put together, adduced in evidence and analysed by a trial judge involves considerable challenges. The focus of this article is to discuss how a judge might be assisted in handling such evidence. There are various options. One relatively new technique is to use an assessor.


The first issue to consider is whether the trial judge should decide the technical issue for himself or refer it to a special referee. There are difficulties with the use of referees in class actions: it further fragments proceedings with undesirable consequences; and, given the large stakes involved, a challenge to the special referee’s determination would be likely. A course that might appear to have superficial allure might not avoid the judge ultimately having to deal with the technical issues directly. Even if one thought that a special referee could be used, it might be difficult to hive off the purely technical issue from other lay factual questions that may involve credit issues which the judge ought to decide. Further, for some technical questions, it may be difficult to separate the technical question from a legal question if one is construing and applying a statutory phrase.

The second issue to consider is whether a limitation should be placed on the number of experts that each party can call. No doubt it is desirable to avoid duplication of expert evidence called by a party, but to place a limit on the absolute number of experts to be called by a party may not be feasible. Take a case involving, say, the failure of a pressure vessel in a gas processing plant. To assess why the vessel failed you may need a metallurgist, a finite element modeller, a mechanical engineer and a physical chemist. Each side may need four separate experts. Limiting each party to one or two experts would not be sensible.

The third issue to consider is whether the court should appoint its own expert. On the example just given, this may not be practical. If there are multiple scientific or technical areas that need to be studied, having one or two court-appointed experts may not cover the necessary disciplines. Moreover, the perceived advantage of a court-appointed expert having the necessary independence from the parties should not be carried too far. All experts come with their own biases for a particular theory or for a particular paradigm in a particular field. If a court-appointed expert is to be useful, you want someone at the cutting edge of the particular discipline under scrutiny. Yet that person may already have a preference for the particular theory of one party over another. Further, depending on the particular area under consideration, there may be a limited number of experts in Australia or internationally that are appropriately skilled. Further, the parties may have already soaked up the leading candidates. The candidates left may not have sufficient quality or may not be available. There are also advantages in allowing the parties to select their own experts who can then debate the issues, canvassing and closely scrutinising the competing views for the judge to then adjudicate on. Such an advantage flowing from this competitive tension may be lost by using a court-appointed expert.

The fourth issue to consider is how expert evidence is adduced at trial. Much has been written concerning the use of expert conclaves, joint reports and concurrent evidence sessions;[1] there is little doubt as to the advantages of these procedures. The discipline in preparing a joint report encourages each expert to rethink their position; if they still disagree, they effectively have to justify their disagreement to their peers. A joint report narrows the issues for the judge, which assists him to focus on the real technical questions in dispute. A joint report is also useful for counsel as the commencement template for crossexamination. Generally, a joint report reduces the time taken in the concurrent evidence session. Concurrent evidence sessions also have considerable advantages. Such a process disciplines the behaviour of all experts who participate in such a session: they may not try to get away with as much if their peers are present to correct them. Further, if counsel has not appropriately followed through on an answer in crossexamination, their own expert is present to pick up on the point. Generally, concurrent evidence sessions narrow the real issues in dispute. Moreover, the judge is more likely to engage directly with the experts and their debate.

The fifth issue that I would like to discuss in more detail is the use by the judge of an assessor who can sit with the judge to help him assimilate the expert evidence. This undoubtedly adds expense, but can be justified in some cases, particularly class actions. An example is the recent Victorian Kilmore East bushfire class action.


Judges are required to quickly grasp unfamiliar scientific and other technical concepts, but particular difficulties are presented when highly technical evidence is adduced by the parties. Quantitative evidence such as mathematics, statistics and their inbuilt formulae may be challenging to grasp, and more so than qualitative evidence (for example, in the economics field relating to questions of market power or substantial lessening of competition).

Further, rather than clarifying matters, an expert witness called by a party may interpret or give evidence in a manner that is biased to the party who engaged them. The judge is not assisted. Conflicting and largely unhelpful expert evidence may be the consequence. Such disadvantages have been ameliorated by relatively recent procedural developments such as an expert witness code of conduct (see The ‘Ikarian Reefer’ [1993] FSR 563), joint meetings of experts, joint reports, concurrent evidence sessions and the like. But engaging an independent assessor whose sole duty is to the court can have additional benefits. Assessors appointed by the court can perform a variety of functions at the discretion of the appointing judge at the pre-trial, trial and post-trial stages of a proceeding. These include:

(a) acting as a human primer to deliver tutorials to the judge pretrial on relevant specialised topics (see for example Kirin-Amgen Inc v Hoechst Marion Roussel Ltd (No. 2) [2004] UKHL 46; [2005] RPC 9, 169 at [135] per Lord Hope of Craighead);

(b) explaining the expert reports, including any joint report;

(c) answering questions that a judge might have regarding the technical evidence;

(d) sitting with a judge at trial to listen to the technical evidence and to help the judge understand it in and out of court;

(e) assisting the judge with any basis or relevance evidentiary objections in an unusually complex technical matter;

(f) putting questions directly to counsel or witnesses at the hearing or suggesting questions for the judge to put to counsel or witnesses;

(g) generally, acting as a discipline on the behaviour of expert witnesses in a concurrent evidence session who may otherwise perceive that they can confound the lawyers present with technical complexity without challenge;

(h) conferring with the judge after trial to assist the judge to get the technical concepts correct; and

(i) reviewing draft judgments for technical accuracy, but solely against the evidence adduced by the parties.

The assistance of assessors could provide added confidence to the appointing judge as to the cogency of the judge’s technical reasons. At the least, the reasons would be based on a deeper understanding of the technical evidence in a field with which the judge may not be familiar. In Beecham Group Ltd v Bristol-Myers Co (No. 2) [1980] 1 NZLR 192, Barker J commended such assistance provided to him by an adviser (equivalent to an assessor).

Moreover, the assistance provided by an assessor to the judge to understand complex and conflicting technical evidence may reduce the length of a hearing.


The use of assessors in proceedings has been criticised for a lack of procedural fairness, an impermissible delegation of judicial power and the delay and expense involved. But such criticisms have been underwhelming.

Procedural fairness

Parties may resist the notion of the ‘private’ use of an assessor by a judge in chambers. Without the opportunity to comment on assistance provided by an assessor, there may be concerns about the potential for a lack of procedural fairness.

This perceived lack of procedural fairness was addressed by Heerey J in Genetic Institute Inc v Kirin-Amgen Inc (No. 2) (1997) 78 FCR 368 (Genetic Institute), but was not considered as being a valid ground to oppose the appointment of an assessor. J Forrest J in Matthews v SPI Electricity & Ors (Ruling No. 32) [2013] VSC 630 likewise perceived there to be little difficulty, provided that any necessary disclosure was made.

The issue of a perceived lack of procedural fairness has also been considered by English courts in the admiralty jurisdiction,[2] in particular, with respect to art 6(1) of the European Convention for the Protection of Human Rights and Fundamental Freedoms 1950 (Sch 1 to the Human Rights Act 1998 (UK)) (art 6(1)), which provides that litigants are entitled to a fair and public hearing within a reasonable time, by an independent and impartial tribunal established by law. This requirement arguably conflicted with some aspects of the earlier practice of using nautical assessors, where assessors would provide advice to the court without the parties having the opportunity to comment thereon.

In Bow Spring (Owners) v Manzanillo II (Owners) [2005] 1 WLR 144; [2004] EWCA Civ 1007 (Manzanillo), regarding a dispute arising from a nautical collision, the Court of Appeal held that the practice of an Admiralty judge putting questions to assessors after discussion with counsel was appropriate, but should also be complemented by the practice of disclosing to counsel the assessors’ answers in order to comply with art 6(1).

This approach has contributed to establishing a more transparent procedure, allowing counsel to make appropriate submissions, orally or in writing, as to whether the judge should accept an assessor’s advice. This updated procedure has been viewed as being more consistent with the notion — implicit in the concept of a fair hearing — that the parties ought to have the opportunity tohave knowledge of, and comment on, all evidence adduced or observations filed, with a view to influencing the court's decision’.[3]

This approach was followed in Global Mariner v Atlantic Crusader [2005] EWHC 380; [2005] 1 CLC 413, where the Admiralty Court (Gross J, sitting with nautical assessors) expanded upon Manzanillo to recommend that the following procedure be adopted where nautical assessors have been appointed:

• The range of topics on which advice may be sought from the assessors should be canvassed with counsel, at the latest, by the stage of final submissions.

• The questions asked of assessors by the judge should not stray outside the range previously discussed with counsel.

• The questions ultimately put by the judge, and the assessors’ answers, should be disclosed to counsel before the draft judgment is handed down.

• Counsel should thereafter be given the opportunity to make submissions to the judge as to whether the assessors’ advice should be followed.

Generally, there seems to be no compelling reason, based upon any perceived procedural fairness difficulty, to oppose the appointment and use of assessors. Moreover, the peculiar problems that arose in the UK in the admiralty context are not applicable where no formal advice (for example, in the form of a report or answers to questions) is being given by the assessor to the judge; but if such advice is given, it can be addressed in a similar fashion.

Impermissible delegation of power

In relation to the Federal Court, there are also potential issues under Ch III of the Constitution as to whether what is involved is an impermissible delegation of judicial power to assessors (Harris v Caladine [1991] HCA 9; (1990) 172 CLR 84). But the better view is that no such delegation occurs by the use of an assessor, providing such use is properly limited (Genetic Institute).

Delay and costs

It may be said that assessors add to delays and costs.

It has been asserted that assessors may arguably increase the work and time taken by a judge to conduct and decide a case (for example, if the judge spends long periods of time in consultation with an assessor, the assessor poses numerous questions at a hearing, or judgment is delayed due to the consideration by an assessor of a draft judgment). It has been asserted that evidence is double-handled, which adds to costs. But, equally, it may be said that with a better understanding of the evidence, a judge will perform his function more quickly and to a higher standard. The experience in the Victorian bushfires class action litigation suggests that this delay argument has little substance.

Further, it may be argued that parties’ costs are necessarily increased by the use of assessors, whether flowing from delay or otherwise.

In terms of who bears costs, there are several possibilities. First, the costs of assessors could be imposed on the parties. Second, the costs could be borne by the court.

The position in some jurisdictions is that the incidence of costs is usually borne by the parties (see, for example, the position in Victoria, [4] the UK and NZ[5]). For example, under r35.15(5)-(6) of the Civil Procedure Rules 1998 (UK), an assessor’s remuneration is to be determined by the court and form part of the costs of the proceedings. The court may order any party to deposit a sum for the assessor’s fee before the assessor commences his role. The White Book at [2A-142] states that the usual practice has been for the claimant to pay the remuneration of the assessors on demand after the case has concluded.[6]

To impose the costs burden on the parties is both unremarkable and justifiable. The type of case that is likely to justify the use of an assessor will usually be a commercial case or a class action where the expenditure is warranted. In such a case, both the technical complexity and the sum of money (or importance of the issue) involved will usually justify the additional expenditure; such expenditure would not be disproportionate to the context.[7] Further, if the judge indicates a need for such assistance,[8] it is unlikely that the parties would seriously contest such an appointment or an order that the parties bear the costs equally in the first instance; the ultimate incidence could await the outcome of the trial.

The other possibility is for the court to fund the provision of assessors. However, this is not recommended. The use of assessors is likely to be ad hoc and justified only in unusual cases. The use of an assessor is quite expensive, particularly if the relevant expertise needs to be obtained from outside Australia, the trial is lengthy or multiple assessors need to be used. Budgeting for such expenditure would prove difficult. Moreover, if the use of an assessor is justified in order to ensure a more appropriate and informed adjudication of the technical issues, then there is no good reason why the parties ought not to pay for the assessor as a necessary incidence of bearing the costs in running the trial.

Other administrative considerations

There may be difficulties in identifying an impartial assessor, particularly where a discipline may involve two competing paradigms of theory on a particular issue.[9] An assessor may be committed to a particular side of the debate (a literature search can reveal this); further the pool of candidates may be limited if the parties in the matter have already engaged the leading experts in the relevant discipline;[10] further, prospective assessors may have limited availability or need substantial advance notice to make themselves available for pre-trial, trial and post-trial assistance.[11]

But none of these perceived problems is insoluble. Parties could be required to agree on a particular assessor or directed to agree on a list of proposed assessors. Once this occurs, the court could contact each candidate to determine their availability and select from that list.


Different jurisdictions have different statutory frameworks empowering courts to appoint and use assessors. There is no standard definition of the term ‘assessors’ or delineation of their role and function in courts.[12] The assistance provided by assessors can range from, on the one hand, helping a judge to understand expert evidence to, on the other hand, the giving or taking of evidence.

Federal Court context

The Federal Court of Australia Act 1976 (Cth) (FCA), Native Title Act 1993 (Cth) and Patents Act 1990 (Cth) expressly provide for the appointment of assessors by the Federal Court.[13] Moreover, plenary powers such as s33ZF of Pt IVA of the FCA may facilitate the appointment of assessors. However, in practice, the appointment of assessors is relatively rare.[14]

In the native title context, ss83, 88 and 93 of the Native Title Act give the Federal Court power to appoint assessors to inter alia take evidence and hold conferences. Sections 37A37L of the FCA also provide for the appointment of assessors in native title proceedings.[15]

In the patents context, the power to appoint assessors has existed since 1903, but has been used only a handful of times, most notably by Heerey J in Genetic Institute. Section 217 of the Patents Act 1990[16] provides:

‘A prescribed court may, if it thinks fit, call in the aid of an assessor to assist it in the hearing and trial or determination of any proceedings under this Act.’

In Genetic Institute, the applicant sought an order for the appointment of an assessor under s217. The application was opposed on the ground that the technical matters in issue did not present real difficulties for the judge. His Honour disagreed, holding that the appointment of an assessor was desirable. Drawing assistance from Beecham Group Ltd v Bristol-Myers Company [1980] 1 NZLR 185, his Honour found that the court could determine the limits of any assistance provided by an assessor, and no great harm would occur if the assessor was ultimately redundant. His Honour found that s217 did not posit a criterion of ‘judicial inadequacy’ as a precondition. Rather, it was simply a question of ‘whether the judicial task [could] be better performed’.

The opposing party also submitted that any delegation of power to an assessor was invalid under Ch III of the Constitution. His Honour found that such a consideration was not relevant, as there was no question of an assessor exercising any judicial function.

Further, in response to the argument that a breach of the rules of procedural fairness might occur where an assessor confers with a judge in chambers, his Honour said that a judge may consult with other judges and is routinely assisted by court personnel whose function it is to aid them in carrying out their judicial responsibility. His Honour also rejected other submissions that the costs of an assessor (to be borne by the parties) was disproportionate, and that it would prove difficult to avoid conflicts of interest as candidates for the role of the assessor would likely have some connection with one of the parties.

An unsuccessful leave to appeal application was made (see Genetic Institute Inc v Kirin-Amgen Inc [1999] FCA 742; (1999) 92 FCR 106). The applicant for leave argued that by having ‘lengthy discussions’ with the assessor after the close of submissions, Heerey J had acted with a lack of procedural fairness. This contention was rejected.

In F Hoffman-La Roche AG v New England Biolabs Inc [1999] FCA 1424; (1999) 47 IPR 105, Emmett J also considered the appointment of an assessor under s217. His Honour considered that the role of an assessor was to ‘assist the court in understanding the complex scientific material that [was] likely to be before the court in connection with the hearing’.[17] He also considered that assessors may not necessarily require the qualifications or standing of an expert witness. They could be considered as ‘human primers’[18] whose function it was to assist the court in understanding complex scientific material.

In the maritime context, under ss258 and 319 of the Navigation Act 1912 (Cth) (now repealed in full), assessors were required to assist a court before which proceedings were brought against a person for an offence against the collision regulations; assessors could also be appointed by a court determining a dispute as to salvage. Further, ss360-363 of the Navigation Act dealt with the appointment of assessors by Courts of Marine Inquiry. These provisions were gradually repealed over time. No commensurate provisions exist in the Navigation Act 2012 (Cth). The abolition of these special provisions dealing with nautical assessors in admiralty reflected the preferred option of the Australian Law Reform Commission set out in its report Civil Admiralty Jurisdiction, Report No. 33 (1986) at [291]. In that report, the Commission concluded that ‘abolishing all special provisions for assessors in admiralty but leaving the general rule (if any) of the court hearing the matter to apply’ represented the least intrusion upon the ordinary powers of courts and supposedly helped assimilate admiralty actions into other civil actions, ‘leaving the fate of nautical assessors to be decided as part of any review of the function of assessors generally’. This option was preferred by the Commission, rather than adopting the English practice of using nautical assessors or allowing the use of such assessors only where all parties had requested them.


The Supreme Court Act 1986 (Vic) (SCA) and Civil Procedure Act 2010 (Vic) (CPA) contain provisions relevant to the appointment, functions and powers of assessors.

Under s77(1) of the SCA, the Victorian Supreme Court may call on the assistance of one or more qualified assessors and hear the proceeding wholly or partially with their assistance.[19] The Court is not bound by their opinions or findings. Under s77(2), the Court may determine the remuneration of assessors.

In addition, s65M of the CPA allows a court to make an order appointing an expert to ‘assist the court’ (s65M(1)(a)) and ‘to inquire into and report on any issue in a proceeding’ (s65M(1)(b)) at any stage of the proceeding.

There is no specific reference to assessors in the Supreme Court (General Civil Procedure) Rules 2005 (Vic).

The appointment of assessors under these provisions is rare. But a recent example is Matthews v SPI Electricity & Ors (Ruling No. 19) [2013] VSC 180, and the related Matthews v SPI Electricity & Ors (Ruling No. 32) [2013] VSC 630, where J Forrest J appointed two assessors to provide him with assistance in relation to scientific and engineering questions relating to the failure of the Valley Span conductor on Black Saturday, including both quantitative and qualitative analysis of the stresses on the conductor. Questions of physics, electrical engineering, mechanical engineering and metallurgy were involved. Because of the diverse range of scientific and technical disciplines, two assessors were required.

His Honour interpreted s65M(1) of the CPA as empowering the Court to appoint an ‘assessor’, despite the language of ‘court-appointed expert’ being used; he also invoked s77(1) of the SCA. His Honour determined that it was ‘clear from both the CPA, the SCA and the Supreme Court (General Civil Procedure) Rules 2005 (Vic) ... that where a judicial officer doubts his or her own ability to deal with a complex matter outside his or her experience or knowledge then there is a way in which the exercise can be made easier and, more importantly fairer’.[20] Further, he did not apprehend any restriction under either s65M of the CPA or s77 of the SCA in the scope of the assistance that could be provided by an assessor. In Ruling No. 32, J Forrest J reiterated that there was no such explicit restriction, summarising his view of the scope of the role of the assessors as follows (at [27]):

‘The primary role of the assessors is to assist the court in understanding the evidence of the experts. Applying the CPA, combined with the principles of natural justice and the guidance from the cases I have referred to, I set out below the scope of the role of the assessors in this case:

(a) The assessors’ role is to assist the judge. The decision is that of the judge alone.

(b) The assessors will sit with me during the concurrent evidence sessions. If they wish, they may question the experts (or counsel) in this context. Such questioning however will be limited to clarification of the evidence; that is, where they consider the evidence to be ambiguous, unclear or incomplete.

(c) I may consult with the assessors while sitting if I find a point of evidence unclear and seek their immediate input as to an appropriate or useful inquiry to make.

(d) I will consult with the assessors whilst in chambers on matters raised by the experts in their oral evidence and in their individual and joint reports. This may include advice as to any questions the assessors think I should ask counsel or the experts in order to determine the questions at hand.

(e) I will seek the guidance of the assessors on technical matters upon which I lack the requisite knowledge to understand without qualified assistance. This may include “lessons” on matters fundamental to, for example in this case, fracture mechanics or vibration.

(f) If the assessors raise a theory or opinion that has not previously been identified by the parties, I will discuss this with counsel.

(g) The assessors may from time to time provide me with advice on matters over which there is dispute between the experts. Such advice is not binding and the determination of a particular issue rests with the judge.

(h) I anticipate that I will consult with the experts immediately after the conclusion of the concurrent evidence session and, from time to time, while drafting the judgment. This is likely to include seeking confirmation from them that I have properly understood the meaning of the expert evidence of conclaves 1, 3 and 4. I repeat, however, that their role is confined to providing advice and ensuring that I have comprehended the evidence given. I also repeat that the decision on these issues is mine and mine alone.’

United Kingdom

Assessors have been used by English courts to assist judges in understanding scientific, technical or medical evidence.

As indicated earlier, Courts of Admiralty have called upon nautical assessors for assistance ‘to advise on matters of navigation and seamanship in collision and similar damage actions, salvage actions and actions in respect of personal injury or death aboard ship’.[21] Historically, the assistance of nautical assessors was provided to a judge alone and generally not disclosed to the parties. The assessors were not called by the parties, were not sworn, and were not subject to cross-examination (The Queen Mary (1947) 80 Lloyd’s Rep 609, 612 (Scott LJ)). Nevertheless, their advice (for example, an answer to a question) was treated as evidence. Although a court assisted by nautical assessors had the discretion to allow the parties to call expert evidence on matters within the expertise of the assessors, the practice was generally not to allow this.[22] The assessors’ advice was treated as taking the place of independent expert evidence that might otherwise be called by the parties. The admiralty context for the use of assessors was idiosyncratic.[23] Moreover, as discussed earlier, the modern practice of the use of nautical assessors by English courts has evolved in response to procedural fairness concerns.

Assessors have also been used in patent cases. Halliburton Energy Services Inc v Smith International (North Sea) Ltd (No. 2) [2007] RPC 17, 436 sets out the early legislative history empowering such a use, now culminating in s70 of the Senior Courts Act 1981 (UK) (previously known as the Supreme Court Act 1981 (UK)). That section makes a distinction between assessors generally (see s70(1)-(2)) and scientific advisers in the patent context specifically (s70(3)-(4)).

Section 54 also provides for the use of assessors and advisers on associated appeals. In terms of advisers, the provisions of r35.15 of the Civil Procedure Rules 1998 (UK) equally apply to them as to assessors.[24] As to costs, and notwithstanding s70(4), it would appear that the parties bear the costs;[25] the specimen directions (order 13) attached to the Patents Court guide (December 2012) provide for the costs to be initially borne in equal shares by the parties and ultimately treated as costs in the cause.

Assessors have also been used more generally; for example, medical assessors have been used in workers’ compensation proceedings. In the more general context, the precise use of assessors has been ultimately at the discretion of the court, so long as they did not exceed the bounds of their function, being so to advise. Apart from the admiralty context, an assessor’s role was not to give evidence. In Richardson v Redpath, Brown & Co Ltd [1944] AC 62 at 70, Viscount Simon LC said:

‘But to treat a medical assessor, or indeed any assessor, as though he were an unsworn witness in the special confidence of the judge, whose testimony cannot be challenged by cross-examination and perhaps cannot even be fully appreciated by the parties until judgment is given, is to misunderstand what the true functions of an assessor are. He is an expert available for the judge to consult if the judge requires assistance in understanding the effect and meaning of technical evidence. He may, in proper cases, suggest to the judge questions which the judge himself might put to an expert witness with a view to testing the witness’s view or to making plain his meaning. The judge may consult him in case of need as to the proper technical inferences to be drawn from proved facts, or as to the extent of the difference between apparently contradictory conclusions in the expert field.’

Although Redpath involved a medical assessor, its formulation of an assessor’s role has more general application to assessors in English courts.[26]

New Zealand

In Beecham Group Ltd v Bristol-Myers Company [1980] 1 NZLR 185, Barker J made orders under the Patents Act 1953 (NZ) providing for the appointment of an independent scientific adviser to assist the court.

The relevant rules of court permitted the court to be assisted by a scientific adviser. Moreover, the court could determine the limits of such assistance.

His Honour considered the submissions in opposition to the appointment regarding the lack of technical difficulty of the case and the uncertainty of the role of an adviser (including the possible transgression of the proper limits of the role of an adviser). He found that this criticism could be ameliorated by the court:

(a) defining the role of the scientific adviser at the commencement of hearing, which in that matter was to consider the submissions and assist the judge in chambers to understand them (and if the adviser proffered a different view, then the judge could seek the comments of counsel);

(b) making clear to the adviser that the legislation reposed the power of decision in the judge alone; and

(c) terminating the assistance of the adviser at the conclusion of the hearing (although, ultimately, his Honour conferred with the adviser after judgment was reserved to ensure that every statement of scientific fact or principle in the judgment was correct; see Beecham Group Ltd v Bristol-Myers Co (No. 2) [1980] 1 NZLR 192).


The option of appointing assessors has been used infrequently. Moreover, they have usually been appointed only in highly specialised litigation. But where assessors have been used, they have considerably enhanced the adjudication process. There is no reason to think that their use would not be advantageous in class actions where appropriate. Many class actions have considerable forensic technical complexity in dealing with common issues such as breach and causation. Further, given the scale of class actions, the use of assessors may not involve disproportionate expense. Using assessors is an option that ought to be considered in appropriate cases.

Justice Jonathan Beach is a judge of the Federal Court of Australia. His Honour is grateful to his associate, Jennifer Daphne Lim BA/LLB (Hons) (Melb), for her first-class research assistance and reflections on the topic.

[1] The use of expert conclaves, joint reports and concurrent evidence sessions has been the subject of some articles in Precedent, most recently in Issue 119 – November/December 2013.

[2] It has also been considered outside that context — see, for example, in the patent context in Halliburton Energy Services Inc v Smith International (North Sea) Ltd (No. 2) [2006] EWCA Civ 1599; [2007] RPC 17, 436 at [18]-[21] and in the race relations context in Ahmed v University of Oxford [2002] EWCA Civ 1907; [2003] 1 WLR 995 where the UK Court of Appeal examined the role of assessors under the Race Relations Act 1976 (UK).

[3] See Krcmar v Czech Republic (35376/97) [2000] ECHR 99; (2001) 31 EHRR 41 at [40]; see also Civil Procedure (Vol. 2), Sweet & Maxwell, 2014 (the White Book) at [2D-84] and [9A-263].

[4] Under s77(2) of the Supreme Court Act 1986 (Vic), the Court may determine the remuneration of the assessors. In the Matthews v SPI Electricity cases, the parties bore the costs of the assessors in equal shares in the first instance.

[5] In Beecham Group Ltd v Bristol-Myers Co (No. 2) [1980] 1 NZLR 192, r7 the Patents Rules 1956 (NZ) made provision for the remuneration of the scientific adviser appointed. With the assistance of the adviser, his Honour ultimately allowed the appeal and awarded the appellant costs, which appeared to include the costs of the adviser (although nothing was specifically said on the point, and also noting that his Honour indicated that he was happy to later receive submissions on costs from counsel).

[6] The prior Practice Direction [1994] 1 WLR 599, now revoked ([2007] 1 WLR 2508), provided for the initiating party to pay the remuneration of an assessor in the first instance without prejudice to any right to recover from any other party if successful in the action (see also the White Book at [2D-142]). On any view, the court itself or Consolidated Revenue did not bear the expense, except perhaps with respect to ‘scientific advisers’ appointed under s70(3) of the Supreme Court Act 1981 (UK) (now the Senior Courts Act 1981 (UK)) in relation to the Patents Court. But even then, such does not appear to have been the case notwithstanding s70(4) (see Halliburton Energy Services Inc’s Patent [2006] EWCA Civ 185; [2006] RPC 26, 653 at [12] and the specimen directions (order 13) attached to the Patents Court guide (December 2012) which provides for the costs to be met in equal shares by the parties in the first instance and ultimately treated as costs in the cause). Section 37C(1) of the Federal Court of Australia Act 1976 (Cth) in respect of native title assessors is a special case.

[7] This depends on the particular circumstances of the case. See Balcombe Group Plc v London Development Agency [2008] EWHC 1392 (TCC); [2008] TCLR 8 as an example of where the High Court of Justice (UK) held that it was inappropriate to appoint an assessor due to the likely expense of the assessor (to be borne by the parties) in comparison with the quantum in dispute.

[8] This could be ameliorated to some extent by ensuring that the judge allocated to the case had some technical expertise. But even then, such expertise may be out of date or relate to a different subject matter than that specifically required in the case.

[9] Justice Peter Heerey, ‘Expert Evidence in Intellectual Property Cases’ (1998) 9 Australian Intellectual Property Journal 92, 96.

[10] Australian Law Reform Commission, Managing justice: A review of the federal civil justice system, Report No. 89 (2000) at [7.156].

[11] Heerey, see note 9 above, 96.

[12] Australian Law Reform Commission, see note 10 above at [6.125].

[13] The appointment of assessors differs from the appointment of court experts under Pt 23 of the Federal Court Rules. Rule 23.01(1) provides that a party may apply to the court for an order appointing a court expert to ‘inquire into and report on any question or on any facts relevant to any question arising in a proceeding’. This provision does not appear to extend to the broader role of assessors to ‘assist’ a court.

[14] Australian Law Reform Commission, see note 10 above at [7.149].

[15] See also r34.128 of the Federal Court Rules, which provides that in native title proceedings a party may apply to the Court for an order that an assessor be appointed to take evidence from a party, decide how evidence is to be recorded and prepare a report of the evidence for the Court and that a person be summoned to appear before the assessor to give evidence or produce documents or other things.

[16] See also Adhesives Pty Ltd v Aktieselskabet Dansk Gaerings-Industri [1935] HCA 83; (1936) 55 CLR 523 at 535, 5612, 565, 571, 580, 602.

[17] F Hoffman-La Roche AG v New England Biolabs Inc [1999] FCA 1424; (1999) 47 IPR 105 at [8].

[18] Ibid.

[19] See also r3.05 of the Supreme Court Admiralty Rules 2010 (Vic), which contemplates the use of an assessor in admiralty proceedings and provides: The trial of a proceeding in the List with the assistance of assessors under s77 of the Supreme Court Act 1986 (Vic) shall take place in such manner and on such terms as the Judge in Admiralty directs. There is no equivalent in the Admiralty Rules 1988 (Cth) or the Federal Court Rules.

[20] See Ruling No. 19 at [16].

[21] Anthony Dickey, ‘The Province and Function of Assessors in English Courts’ (1970) 33 Modern Law Review 494, 499.

[22] Australian Law Reform Commission, Civil Admiralty Jurisdiction, Report No. 33 (1986) at [288].

[23] See also SS Australia (Owners) v SS Nautilus (Cargo Owners), The Australia [1927] AC 145, 153 (HL). In Canada, assessors could also be used in a similar context (Owners of the Ship ‘Sun Diamond’ v The Ship ‘Erawan’ (1975) 55 DLR (3rd) 138).

[24] See Halliburton (No. 2) at [8]-[9] and Practice Direction 63 at [5.10].

[25] See Halliburton Energy Services Inc’s Patent, see note 6 above, r35.15(5)-(6) (but cf r35.15(7)).

[26] However, this view has been criticised as being too restrictive in confining the role of assessors. A broader view may require assessors to answer any question of fact within their special skill or knowledge that is relevant to a case (Dickey, see note 21 above at 502).

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