#14956 - Expert Witnesses - Principles of Civil Procedure

Expert Witnesses

• Adjudication on expert matter than by non-expert judges

• Exception to prohibition on opinion evidence

  • Expert evidence generally based on evidence presented to the expert, or assumptions — rather than on actual observations

  • Usually made to order

  • Unlike ordinary witnesses, the number of possible witnesses is limited only by the number of experts in the field

    • permits imbalance between parties with different resources

    • permits evidence-shopping

  • IE Experts are not really “witnesses” in the traditional sense

• Need for experts — courts not well equipped to resolve disputes without them

Role of the Expert Witness

• Ikarian Reefer per Creswell J — duties and responsibilities of witnesses are:

  • Must be and must be seen to be independent

  • Must be unbiased and should not assume role of advocate

  • Clear description of the facts or assumptions on which evidence is based

  • Make clear when outside expertise

  • qualify opinion with level of certainty

  • Must indicate if change of opinion

  • All information on which opinion based should be disclosed to the other side

• Role

  • Assisting court to understand & assess the factual evidence

  • Generate evidence — eg testing samples, DNA, conducting studies — contributing to factual record

  • Provide opinion — bias is meaningless unless it is extraneous (financial) in nature

• Overriding duty is to assist the court in understanding the evidence

• No immunity from suit for expert witnesses: Jones v Kaney [2011] UKSC 13 (expert admitted to signing off on joint evidence report without reading it)

  • Advocates required to be partisan <> witnesses required to be unbiased

  • Deters credible expert witnesses — concerned about liability

  • Duty to client is of due care, skill & diligence — same as duty to court

Qualification

• USSC Daubert — must be (a) scientific knowledge and (b) will assist trier of fact

  • Whether opinion / theory / technique — has been tested, subjected to peer review, known or potential error rate, general acceptance can be important & known technique which attracts minimal support can properly be viewed with scepticism

  • Admissibility more important when you have a jury?

• <> low bar to expertise, merely goes to weight — Rogers (investigation of plane accident — report had mixture of factual findings & opinions as to cause of accident author of report had job of investigating such incidents — appropriately qualified to do so)

  • TG (care proceedings to remove child from abusive parents — father accused of abuse — father led evidence that baby falling out of chair caused injuries — biomechanical expert purported to give that evidence theory so ungrounded that would not assist — no witness to actual event — father’s evidence was only that baby was found on the ground — no evidentiary foundation)

• Court’s ability to resolve — court doesn’t have expertise

  • Can create specialist courts & tribunals — eg MHC

  • Appoint court’s own expert to assess

    • But raises Art 6 issues — if assessor’s opinion can resolve the matter, there must be an opportunity to comment on their opinion <> if effectively acting as a judge communications should be confidential

    • Common in discrimination cases in the UK

Bias

• Financial interest

  • Contingency fees? Seems inappropriate but plaintiffs may be unable to afford experts otherwise — Factortame

    • Financial interest can be subject to cross-examination, but rarely comes out

  • Experts always have interest in outcome — repeat business from client

• <> Posner — value of evidence diminishes if not considered credible by the court — but distorted by the fact that many cases settle

• Methods of resolution

  • XXN to undermine credibility

  • Admissibility / prohibition

  • Complaints to regulatory body / referrals by court in exceptional cases

Expert-shopping

• CPR 35.4 requires disclosure required when engage expert, permissions required; disclosure of experts in pre-action protocol

  • Don't get costs unless had permissions / can’t lead evidence at any trial

  • Not fully effective — can shop around before seeking permission

• CPR 35.10 — disclosure of expert instructions, but cannot XXN on them unless satisfied that incomplete or misleading

  • Can vary instructions if report not favourable — and...