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(3) Expert Evidence
Should privilege be removed from all expert communications?
Should we prefer court-appointed joint experts or party-appointed experts? If party-appointed experts, should we prefer concurrent evidence?
35.10 (3) The expert's report must state the substance of all material instructions, whether written or oral, on the basis of which the report was written.
(4) The instructions referred to in paragraph (3) shall not be privileged against disclosure but the court will not, in relation to those instructions -
(a) order disclosure of any specific document; or
(b) permit any questioning in court, other than by the party who instructed the expert,
unless satisfied that there are reasonable grounds to consider the statement of instructions given under paragraph (3) to be inaccurate or incomplete.
35 GENERAL NOTES (Higgins and Zuckerman)
Basic conundrum: experts needed to assist court in understanding complex technical/scientific material which requires expertise courts lacks — how is court to assess the reliability of competing expert evidence?
Broadly three main categories of issues with expert evidence:
- (1) Costs: expert evidence has main driver of high costs of litigation
Systems or devices to reduce costs: court control of expert evidence (CPR Rule 35.4) and costs estimates and capping (CPR Rule 35.4)
- (2) Due process: concern whether expert, in practice, is a witness or a judge — See Mantovelli
- (3) Probative value: concerns that expert evidence susceptible to multiple forms of bias
CPR adopted three important measures to address particular problem of "cultural of partisanship" within expert evidence:
- (1) No party may reply on expert evidence without court's permission (and court controls number and nature of experts) (CPR 35.4(1))
- (2) Expert's primary duty is to help the court arrive at a correct decision on matters within expertise (CPR 35.3(1))
- (3) Rules seek to promote party co-operation in experts and to encourage use of joint experts
Admissibility of expert evidence:
- England: Admissibility bar "not particularly high" — admissible where:
1 o (b) there is an acknowledged "body of expertise" (ie. field governed by established principles and rules); and
(c) court considers that expert evidence would assist in the determination of the issues
Cf. United States: focus on admissibility — because of Constitutional entitlement to a jury (consider weight of evidence) judge as the gatekeeper on what gets through to the jury for consideration — Daubert [See case notes below]
After admission, Court to decide weight given to expert testimony: no power to delegate judicial role— court must decide issues (ie. not bound to follow expert)
o If conflicting expert testimony, must set out coherent reasons for accepting evidence of one
No rule of law requiring court to favour expert testimony where conflicting with witness of fact
- CPR 35.3: expert's primary obligation is to the court:
o Duty of experts to help the court on the matters within their expertise.
o This duty overrides any obligation to the person from whom experts have received instructions or by whom they are paid.
- While all witnesses under duty to tell the truth, difference between experts and other witnesses makes it necessary to stress that experts must serve the court:
o (i) retained because they can advance party's case through production of evidence (cf. chosen for fact of witnessing)
o (ii) seek to influence outcome by advancing explanatory theories (cf. merely report based on observation)
o (iii) paid for their evidence (service for profit)
o Thus: CPR 35.3 designed to counteract partisan tendencies— buttressed by CPR 35.10(2): experts to state in report that they understood/complied with duty
- Duties divided into two categories:
o (A) Impartiality: expert to reach conclusion in accordance with evidence/conformity with rules governing subject, regardless of whether conclusion satisfies client
(B) Transparency: expert reports should be comprehensible, clearly indicate underlying assumptions, reasons for conclusions, and any doubts that may remain
- Impartiality goes to probative weight, not admissibility
HOWEVER: Where close personal relationship between expert and client which reasonable observer might think capable of affecting expert's views so as to make them unduly favourable, evidence should not be admitted, however unbiased conclusions might be (Liverpool Roman Catholic Archdiocese Trustees)
o Given decoupling of apparent bias test from expert admissibility, crucial that court be made aware of influences on expert (ie. direct financial interest; employee or other continuing relationship etc) (Factorame) — only if court informed can it consider whether appropriate to allow expert to testify and weight of evidence
- Note: Transparency more important than independence — enables the opponent and court to take account of any lack of independence f
Court's power over expert evidence
- (a) Court permission required for using expert evidence (CPR 35.4)
o Court to determine nature of expert evidence and way it is to be placed before court — ensure that evidence adduced in most effective/economic way consistent
Expert evidence restricted to that which is reasonably required to resolve the proceeding (CPR 35.1)
- (b) Limiting the number of expert witnesses
Equality of arms requires each party be given permission to call same number of experts (although requirement should not be taken too literally)
- (c) Application to change expert or call additional expert
Permission only granted upon showing good reasons and may be conditional
Only in exceptional circumstances allow party to instruct fresh expert without disclosing previous report (deter "expert shopping": Beck; Edwards-Tubb)
o Difficulty where party wishes to disavow expert because expert conceded opponent's case
Party must demonstrate some defect and/or impropriety in expert's change (Stallwood v David)
2 Court would allow party to call another expert only if, regarding all circumstances and overriding objective, further expert evidence "reasonably required to resolve the proceedings" (CPR 35.1)
Guntrip v Cheney Coaches Ltd
(d) Directing expert discussions: Court can require experts to hold discussions to identity issues and reach agreement on particular issues (CPR 35.12)
o 35 PD: Purpose of experts' discussion not to settle cases but to agree and narrow issues — to identify, inter alia: (i) extent of agreement and (ii) points of, and short reasons for, any disagreement;
o Zuckerman: Face to face discussions likely to be conducive to deeper understanding of issues and means of resolving them — softens adversarial posturing:
need to articulate reasons before other experts bound to moderate mercenary loyalty towards retaining party
need for joint report, even if experts indicate dissent, bound to focus minds on core issues and discard marginal disputes
Expert Immunity: Rejected in Jones v Kaney
- Fundamental difference between witness of fact and expert witness (professional provider of services for a reward)
- Baroness Hale (DISSENT): If purpose of immunity is to ensure that witnesses can prepare and give evidence freely to the court, irrespective of whether it might otherwise constitute a tort or a breach of contract, then it should not matter what the source of that liability might be
In context of concurrent expert evidence, where aim is for experts to move towards consensus — removal of immunity risks undermining core aim
- Breach of Expert's Duty and Contempt
Liverpool Victoria Insurance [See case notes below]: Noting finding of contempt of court, consider whether it is necessary to remove the immunity
Disclosure and privilege of experts reports and instructions
- LPP waived in respect of expert reports: CPR 35.10: (3) report must state substance of all material instructions on the basis of which the report was written and (4)
instructions referred to in (3) are not privileged against disclosure
Essential element: for party to know and be able to test in evidence the information supplied to experts in order to ascertain if the opinion is based on sound factual basis or on disputed matters or hypothetical facts yet to be determined by the courts
- Leading authority on extent of disclosure obligation: Lucas v Barking
Protection under CPR 35.10(4) relates to "any specific document" and "questioning in court" unless statement of instructions given under (3) inaccurate/
Important: No requirement to set out all material supplied to an expert — only obligation on expert is to set out "material instructions"
Iceberg problem — all the things that did not lead the expert to conclude in a certain way need not be disclosed
Without full understanding of expert's terms of reference and process leading to final report, difficult to assess expert's conclusions
As a matter of principle, party who waives privilege and adduces privileged material in evidence must disclose material in entirety (to extent necessary to ensure that partial disclosure is not misleading and provide other parties with an opportunity to test the material)
Zuckerman: Decision in Lucas v Barking does little to promote transparency and may therefore need to be revisited
- Instructions of Single Joint Expert entirely transparent (instructions meant to be agreed)
o If the party-appointed expert is theoretically exactly the same, why should the transparency be any different?
- Shortcoming of present approach illustrated in Jackson v Marley Davenport Ltd [Preliminary reports]
o CPR 35.10 refers to expert "actual" evidence, not draft reports (still protected by litigation privilege) HOWEVER: contrary to rules against "cherry picking" in privilege
- Beck and Edwards-Tubb [Reports from different experts]
3 NOTE: Opposite approach to the above (in relation to consultations with the same expert)
Fact that earlier report protected by LP meant that party could not be ordered to disclose the report HOWEVER Court power to make permission to call another expert conditional on disclosure of earlier report (ie.required to waive privilege in first report if intending to rely on second)
Nothing wrong with presenting claimant with price to be paid for court leave to rely on expert B — price is waiver of privilege in relation to expert A.'
Two reasons at forefront of reasoning: (a) CPR ethos of openness (cards on the table) and (b) Need to deter expert shopping
Problem: Inconsistency: multiple consultations with different experts subject to disclosure, but multiple communications with same expert(s) not
oUS APPROACH: "Complete opposite" of English approach
- Federal Rules protect communications between lawyers and expert witness except to the extent that communications relate to expert compensation (including identifying facts/data/assumption that lawyers provided and expert considered in forming opinion)
- Experts must disclose in report — inter alia: complete statement of all opinions witness will express and basis and reasons for them; all 'facts or data' considered; list of 'all other cases in which, during the previous 4 years, the witness testified as an expert, and statement of the expert's compensation in the case
AUSTRALIAN APPROACH: Southcorp: While confidential instructions by lawyer to expert attracts LP, disclosure of expert's report for purpose of reliance in litigation will result in implied waiver of privilege in respect of instructions and documents provided to expert, at least if appropriate inference is that they influenced the report content
- However: Acknowledged difficult to establish at an early stage whether documents influenced content of report in absence of any reference to them in the report.
Single (Court-Appointed) Joint Experts
- CPR 35.7: where two or more parties wish to adduce expert evidence on particular issue, court may direct that single joint expert give evidence
Zuckerman: "enormous potential for good" — cost saving and contribution to quality of fact-finding process (joint instructions, open communication with both parties — more likely to be able to provide objective and balanced view)
- 35 PD 7: Factors the Court will consider when deciding whether to order a single joint expert — inter alia:
o (a) proportionate to have separate experts on particular issue with reference to (i) amount in dispute; (ii) importance to the parties; and (iii) complexity of the issue;
o (c) expert evidence is to be given on the issue of liability, causation or quantum;
o (d) expert evidence falls within a substantially established area of knowledge (ie. dispute or range of expert opinion unlikely)
Continental Experience — Delegation or Abdication of Judge's Role
- Problem of the "almighty" — yet not infallible — expert:
- Judge appoints expert because judge not familiar with technicalities— fear that judge cannot properly correct/identify mistakes made by court-appointed expert —
illustrated by practice: judge rarely ever deviates from expert conclusions — reasons court gives for judgment often largely consist of quotations from the expert's report
- Create a situation in which decision-making is effectively delegated to expert (Verkerk)
- Note: Noting "almost inevitable" "compelling influence" of single expert, especially in complex areas — serious risk that expert usurps court function
35 PD 7(e) — Distinguish between cases where: (i) substantially established area of knowledge (unlikely to be dispute); versus (ii) likely to be range of expert opinion
English courts warned off ordering a single joint expert in (ii) — adversarial expert evidence is more appropriate
4 Testing Evidence of Single Joint Experts
- Starting point: unless reason for not having single expert, should be only a single expert
- Parties must have adequate and equal opportunity to:
o (a) participate in instruction of experts and processes leading to the formation of their opinions; and
(b) challenge the expert's conclusions (Peet v Mid-Kent Healthcare)
- Calling Further Evidence: Where parties agree to single joint expert, and expert produces report, court may permit party to instruct own expert only if good reason
Court must exercise discretion to permit new expert in a way which is consistent with (i) aim of the single expert procedure, and (ii) the need to allow parties a reasonable opportunity to challenge the joint expert's testimony
Facts to be taken into account: Cosgrove v Pattison: nature and number of issue(s); reason new expert is wanted; amount or importance of issue at stake; effect of permitting further expert evidence on conduct of trial; delay new expert will cause; any other special features of the case; and overall justice to the parties
Concurrent Evidence — CJC Report — based on judicial feedback
- (a) Time savings: trial time saved by hot-tubbing — HOWEVER: no saving of time during preparation (pre-trial time required to be devoted to master the details of the case sufficiently to lead the questioning may outweigh time saved at trial)
- (b) Reliability of evidence: 83% judicial respondents considered quality of expert evidence improved HOWEVER 60% experts considered improvement and 30% said no
- (c) Assistance in (current) determination of dispute: 100% of judicial respondents confirmed
- (d) Cost saving: Costs not necessarily saved
- HOWEVER: While CJC Review involved survey of small sample of users and select group of judges, claims to have "tested whether [Jackson's] rationales were being achieved" — review reliant on the opinion of non-experts about value and quality of expert evidence and own assessment of ability to comprehend the evidence (Edmond)
o Evidence for effectiveness of concurrent evidence "largely anecdotal and impressionistic" (Edmond)
o HOWEVER: What would a reliable method of empirical research look like in this context? Who judges the judges?
Consider: Choice between court-appointed (joint) expert and party-retained experts may simply be a matter of which bias we think is the lesser evil
Court Appointed Experts v Party Experts: which is better?
Problems with the pure adversarial system:
- (1) Party selection of experts means counter or neutral opinions suppressed
- (2) Party experts apt to be biased
- (3) Rival expert reviews apt to polarise position of parties (rendering compromise more unlikely)
- (4) Substantial costs (at least one professional and technically lay lawyers to cross-examine opposite expert)
- (5) Substantial repetition of background material (increasing costs)
- (6) Tribunal technically lay body trying to decide between detailed matters of expertise
Then: Objections to the alternative court-appointed expert:
5 (1) How does court find the 'right' person?
(2) How does that person receive the 'right' instructions?
(3) What if party considers court-expert wrong (factually or a matter of professional opinion)? Cross-examine or call contrary expert evidence?
(4) Court expert really becomes, in effect, the judge?
Davies (court-appointed experts): Expert duty to the Court "merely a pious hope" — no real legal sanctions
- Given that expert's evidence is of opinion, close to impossible to prove expert did not actually hold that opinion
- While some professional bodies may take disciplinary action, bodies are not really equipped for this role
o (a) Most experts not partisan — most (part. those who give evidence regularly) genuinely try to assist Court
(b) Real sanction is a "serious slagging off by the Judge" — practical effect may be serious in terms of impact upon work
(c) [Related] Risk to reputation and respect among colleagues
ARGUMENT: Testing evidence is best way for trying to get at the truth — when conducted by skilled cross-examiners, will get as close as can be done
- HOWEVER: cost (time and money) is immense — impractical and unconstructive to insist on procedure for all cases
Thus: when stake's high, side with party experts — single expert likely to produce less reliable result and less likely to be perceived as
- Note: "Of one thing I am sure. There is no "perfect" way of going about expert evidence"
NOTING that practice of expert evidence has led to:
- (a) adversarial bias and subsequent polarisation of expert views
Adversarial system requires lawyers to "sell" the client's version of the truth
(i) Polarisation of opinions: encouraged to emphasise aspects of opinion to support client version and downplay those that do not
(ii) Adversarial bias: Almost inevitable consequence— human tendency to feel need to favour side you "represent"
o Two consequences: judge: (i) may never hear real question (let alone solution) and (ii) likely persuaded by more persuasive personality
- (b) increasingly difficult scientific and technical questions coming before non-expert judges
Adversarial presentation likely to increase risk of misunderstanding — more complex question, more difficult to determine polarisation
- (c) increasing time and money being spent in preparation for trial
And wasteful — time on (cross)examination not designed to assist judge in resolving question — rather, to persuade judge of client's
Argument: Court-appointed experts would lead to elimination of many of the problems inherent in the system:
- (1) Eliminating party-appointed experts eliminates experts with adversarial bias (expert as witness of the court)
- (2) Eliminating adversarial bias gives increased confidence to judges in seeking and relying on assistance in understanding and resolving issues
- (3) Costs substantially reduced — fewer experts, cross-examination shortened and differences of opinion narrowed (or eliminated)
6 Privilege and Immunity: Problems of Expert Evidence Argument: Litigation privilege between expert witness and client inconsistent with role of expert (overriding duty to court) and should be treated as waived by act of disclosing (serving) expert report (extends invitation to the court to treat witness as an independent source of assistance)
(1) Introduction of CPR Part 35 as evidence of a perceived problem — ability of party to manipulate expert evidence to strength case
(2) Key problem to detection and correction of flawed expert evidence: litigation privilege enables litigants to keep some dealing with expert secret — tends to prevent discovery of experts being manipulated by clients or favouring them inappropriately
(3) Case law against removal of privilege:
- Lucas v Barking: Expert compelled in report to set out substance of material instructions relied upon (ie. privileged revoked in that respect)
however, unless real reasons to believe that expert has not do so, disclosure of instructions not ordered
EWCA accepted that privilege between experts and clients is worth protecting (ie. overriding duty to court not inconsistent with survival of private right of communication between party and expert)
o Argument: Decision neutralised the CPR aim of creating transparency
- Jackson v Marley Davenport: Reports not intended for disclosure privileged, because they came into existence for purpose of litigation
Privilege not abrogated— by serving report, party waives privilege, but not in any other document expect to the limited extent above
In effect: if documents referred to in expert report cannot be inspected because part of the "instructions" and expert is trusted to have set out material part of those "instructions", material not referred to in report not disclosed because of privilege
(4) Loss of privilege should follow creation of duty to court — duty arises when party discloses expert opinion as material to be relied on
- Disclosure of the report changes the status of the expert witness — from private adviser (acting under contract and duty to client alone) to individual with an overriding duty to the court
Cannot fulfil duty to court while keeping relevant material secret
- Waiver of privilege should extend to all communications between party and expert (including earlier reports and drafts)
The Causes and Manifestations of Bias in Civil Expert Evidence
NOTING that bias in expert evidence significantly hinders Court in deciding case and increases costs — two related questions about classification of bias:
- (a) What do we mean when we say that expert's evidence is "biased"?
- (b) How should we distinguish such bias from genuine disagreement?
(1) Potential bias is important consideration for Court in assessing admissibility and weight of evidence — importance heightened in relation to assessment of expert evidence (by definition, expert providing opinions that lay tribunal would not be competent to form) and especially single experts
- Concern that experts "hired guns" and "adversarial weapons" were "primary drivers" for express recognition of duty to court and extensive CPR
(2) Causes of expert bias
(i) Personal interest
(a) predisposition: moral opinions, personal relationships, membership of body etc (eg. Liverpool Roman Catholic Archdiocese)
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