Managing experts and their evidence is one of the most important, yet fraught, skills of a lawyer.  If it is not done correctly, expensive evidence can be limited or even excluded by the Court.  So what are the dangers, and the tips for avoiding mistakes?

How Should Experts Be Engaged?

Particularly since the introduction in most Australian superior Courts of guidelines for experts, there is a need for great care in retaining experts.  The expert, and the lawyers involved in dealing with him, must be familiar with and apply the relevant Court guidelines.  That is, each should assume from the outset of the relationship that the expert may be called upon to give evidence and if this should occur, will be bound by the guidelines.

Broadly, an expert should be retained by means of a letter of retainer which clearly sets out the instructions, the issues to be addressed and any assumptions to be made.  It is preferable to ask the expert witness to make assumptions of fact rather than to provide a draft statement or a proof of evidence for another witness, or the client, which turns out later to be a draft statement or proof from which the witness or the client may wish to resile.  This is because the draft statement or proof of evidence will not be privileged in the hands of the expert if the report is relied upon in the proceeding.  The instructions as set out in the letter of retainer must be clear and unequivocal.

A copy of the letter of retainer should be produced to the opposing parties with the report itself.  The applicable Expert Witness Code of Conduct, relevant Practice Directions, (where applicable) the Civil Procedure Act 2010 (Vic)(CP Act) and common sense suggest that the letter of retainer ought to refer to at least the following:

  1. The fact of the retainer of the expert;
  2. The functions to be performed by the expert beyond preparing the report, if there are to be any;
  3. The timing of the report.
  4. The form of the report.
  5. The manner in which the expert is to conduct himself.
  6. A summary of the issues appearing in the pleadings that are relevant to his report;
  7. Guidance concerning any legal issues that are relevant to the completion of the expert’s tasks.
  8. A summary of the facts that may be relevant to the expert’s report.
  9. Any assumptions that must be made by the expert in completing his report, and the expert should be instructed to reveal in his report the process of reasoning by which he arrives at the opinions which he professes to hold.
  10. The statistical and mathematical models that may be utilised by the expert in the preparation of the report which involves the valuation of an asset, and a suggestion to the expert that he discuss in the report which model is appropriate and why;
  11. Guidance concerning the requirements imposed upon the expert by the Court in which the expert is to give evidence.
  12. The specific questions that the expert is to answer.  

How Should Experts Be Managed?

The principles applying to experts intended to be called as witnesses may be reduced to the following general principles:

  1. The expert witness has an overriding or paramount duty to assist the Court and is not an advocate for the party calling him.
  2. An expert must be, and must be seen to be, independent and impartial.  Thus 'coaching' of experts is improper.1   However, in FGT Custodians v Fagenblat [2003] VSCA 33, the Victorian Court of Appeal affirmed the decision of the Trial judge not to exclude the evidence of an expert on the grounds of ostensible bias.2 The Court held that there is no common law principle which would exclude as incompetent the evidence of a person otherwise qualified to give expert testimony but who is said to be affected by interest or bias, at least where that interest or bias is said to arise from some family or personal relationship between the expert and the person calling the expert.3
  3. An expert’s evidence ought to be transparent in the sense that all facts or assumptions upon which his evidence is based should be stated, his reasoning should be set out, and unfavourable facts or considerations which have been dismissed should be discussed and explained.4
  4. The documents with which the expert witness has been instructed will be discoverable.5
  5. Legal professional privilege is unlikely to attach to communications with the expert if he is relied upon as a witness.6
  6. Waiver of legal professional privilege in relation to witness statements is now generally determined by section 122(2) of the Evidence Act.  Calling the relevant expert as a witness is usually conduct that waives privilege in the communications by being inconsistent with the maintenance of the privilege.  Further, convening a meeting of several experts called by the party including the expert in question is usually inconsistent with maintaining the privilege – Roads Corporation v Love [2010] VSC 253;
  7. A draft report may be called for when the expert is in the witness box.7
  8. The Court is interested in the expert’s opinion, not the lawyer’s opinion.  Therefore the report or evidence of the expert needs to be primarily (perhaps solely) the product of the expert’s endeavours.  Involvement by the lawyers in the drafting process of an expert’s evidence or report is to be avoided as much as possible.
  9. If, when the report is received, there is an error in relation to a factual matter or there is another hypothesis which the witness is to be asked to explore, then supplementary written instructions should be provided and the witness asked to comment.  If there are problems of form because of the expert’s inexperience in report writing, written guidance rather than legal re-writing is the safest course to adopt.
  10. The relevant Practice Direction (and if applicable, the relevant provisions of the CP Act) should be provided to the expert when being retained or as soon as practicable thereafter, and acknowledged by the expert as having been read and understood.  If applicable, the expert must in his report acknowledge that he or she has read the Expert Witness Code of Conduct or relevant Practice Direction and agrees to be bound by it.
  11. A “team approach” to the litigation which includes the expert is fraught with danger.8   Those exposed are the expert, the lawyer and the client.
  12. Generally speaking, legal advice ought not be provided to the expert witness because to do so may compromise the independence of the witness and if provided, is likely to have the consequence that privilege has been waived and the advice will become available to the opposing parties.  Some issues between experts are the result of the questions posed to them being based on different legal views being taken of, for example, the statutory construction to be used.9  However, it may be essential to provide such legal advice in certain cases.  Corporate lawyers are likely to be familiar with the initial problem of an expert witness who is asked to value shares in a company as part of the claims made in a shareholder oppression action.  An inexperienced expert witness might readily value the shares using concepts known to economists and/or accountants, but give a different view once a proper appreciation of the considerations to which the Court will have regard in valuing the shares is explained.  Another example might be where an expert as to inventive step (obviousness) in a patent revocation case may be dismissive of developments over the prior art as routine until the ‘scintilla of inventiveness’ principles are explained.  Any such explanation would of course need to be transparent, neutral and uncontentious.  There is a particular need to instruct the expert in the meaning of obviousness in a patent law sense before he is allowed to opine on the issue.  In Aktiebolaget Hässle v Alphapharm Pty Ltd (2000) AIPC 91-636 at [69] the Full Court said:

"Such evidence ought not to be received unless it is first demonstrated that the expert understands the concept of obviousness as explained in the 1990 Act and the authorities."

  1. Exchanging draft reports with legal advisers and other experts within the team should be avoided.  The legal adviser coordinating the case should make sure that reports by one expert upon which the opinion of another depends are finalised in a timely manner before being provided to that second expert.  Conferences and other forms of communication between experts for the same party should be avoided (see above para 13(b));
  2. The process of communication between the lawyer and the expert should be transparent.  If it is not, then questions as to the independence of the expert may arise.  The exchange of emails and draft reports, constant conferencing between legal practitioner and expert, with or without client, are not only expensive processes, they are likely to be counterproductive.  Practitioners should assume that all their communications with the expert (and on behalf of the expert, for example, in obtaining instructions requested by the expert) will be discoverable.
  3. Evidence going to the ultimate issue is, by reason of section 80 of the Evidence Act, strictly admissible in a proceeding.  However, expert evidence is not a panacea.10  Whilst experts are allowed to address the ultimate question in a case, they are not to be allowed (or should not be assumed to be able) to subvert the function of the court in deciding the case.11  In Durajay v Aristocrat (2005) 147 FCR 394 Stone J held at [42] that the Court should exercise particular scrutiny when the expert moves close to the ultimate issue, as the expert may move outside his or her field of expertise or express views unsupported by disclosed and contestable assumptions.12
  4. Experts must also be used carefully so as not to infect them with impermissible hindsight, especially when engaged to assist in attacking the inventive step of a challenged patent.13
  5. Use of experts in an interlocutory application (e.g. injunction) whilst rare, should probably be governed by the same principles as at trial.  The evidence of the expert witness should be direct (that is, from his or her own knowledge) lest it be held to be hearsay.  Putting it differently, the exception to the hearsay rule created by section 75 in relation to interlocutory proceedings seems not to be an exception to the opinion rule in section 76.14  

Dangers in Managing Experts

Ignoring or breaching any of the above principles can have serious detrimental effects on the litigation.  These consequences fall into six broad categories, which may often overlap:

  1. Discovery – it seems privilege does not attach to the final form of any witness statement, although the drafts may still enjoy privilege.15   But even then, a claim of legal professional privilege attaching to the expert witness can be rejected and was rejected in Temwell16  where Ryan J refused to give any privilege protection to the extensive input to the expert’s report by the solicitors.  This resulted in the many drafts of the report being discovered, the discovery of hundreds of emails passing between the solicitor and the expert, the solicitor’s file being discovered and the solicitor being cross-examined for several days.
  2. Cross-examination – the Temwell case resulted in the solicitor being cross-examined for several days.  In the Pivot case, the expert was cross-examined extensively concerning his apparent belief that it was legitimate for him to be part of the team trying to win the case.  This significantly detracted from the weight of his opinion.
  3. Weight – reduced weight may be given by the Court to the evidence of the expert.  This can happen where the subject is not suited to expert evidence17  or where the Court concludes that an expert has become a protagonist for a party.  There cannot be much doubt that in the Temwell, Pivot and Qantas/Air New Zealand cases the Courts took a dim view of the conduct of the solicitors and experts and the weight of the expert’s evidence was accordingly significantly diminished.
  4. Comparison between experts - the failure by an expert witness to adhere to the Guidelines by properly setting out in the report the factual and analytical basis on which he or she expresses the opinion contained in the report can impinge upon whether the evidence of the expert concerned is preferred to the expert evidence given by an expert witness called by an opposing party.  For example, in Abigroup Contractors Pty Ltd v. Sydney Catchment Authority (No. 3) [2006] NSWCA 282, the New South Wales Court of Appeal considered how to address competing expert evidence, and did so by having regard to whether the experts concerned had given adequate reasons in the form of their examination and analysis of the evidence in the case.
  5. Exclusion – in an extreme case the expert’s report can be excluded altogether.18   A recent example of this was where the rule relating to experimentation was breached.  FCR 34.50 requires that if experimental proof is to be used as evidence, the opposing party must be allowed an opportunity to attend such experimentation.  In Bayer Pharma v Generic Health19, Jagot J found that the rule applied to the experiment conducted to show that tablets made according to a method in a prior art document dissolved in accordance with the claim 3 and 11 dissolution test, and therefore that the prior art document inherently anticipated the claims.  Her Honour also found the rule was breached and concluded the evidence must be excluded.  The result in the merits of the case was that the attack on the patent failed and infringement was found.
  6. Costs - The Court or Tribunal may in appropriate circumstances make a costs order against an expert witness who, by his evidence, causes significant expense to be incurred, and does so in flagrant or reckless disregard of his duties to the court.20  Where the litigation is conducted subject to the CP Act and the Court determines that an overarching obligation has been breached by the expert, then the Court may, pursuant to section 29 of that Act, make an adverse costs order against the expert personally, and also require the expert to pay compensation.  It is also possible that the Court may in such circumstances conclude that the legal practitioners responsible for calling the expert have also breached an overarching obligation arising out of the conduct of the expert.  The Court may act of its own motion under the CP Act in investigating such matters.  An adverse costs order may thus also be made against the party who called the expert, and the legal practitioners for that party.21 

As a general rule, and subject to any statutory exception such as that found in section 29 of the CP Act, witnesses in Court including expert witnesses enjoy immunity from suit in respect of evidence given in Court.22   The immunity has been extended to reports and affidavits prepared for litigation and in some cases to preparatory documents.23   However, the immunity of expert witnesses from suit has recently been reviewed by the United Kingdom Supreme Court in Jones v Kaney [2011] 2 AC 398.  In that case, the Court decided that there was no justification for continuing to hold expert witnesses immune from suit in relation to the evidence they give in Court or for the views they express in anticipation of Court proceedings.  The judgment in Jones v Kaney contains a detailed examination of the rationale for the immunity and reasons supporting its abolition.  Whether Australian courts will adopt a similar approach remains unclear, although the most recent decisions in the Supreme Court of New South Wales suggest that the decision in Jones v Kaney will not be followed in Australia, at least until the High Court determines that it should be.24 


If it was not already obvious, I recommend that great care be exercised in handling experts and their evidence lest effort and expense be wasted, or worse, one's case be harpooned.