Barrister and experienced mediator Mark Tottenham outlines the primary duties of an expert witness.
(The expert witness – Part 1, by John Garrett, can be read here.)
Recently in Australia, a psychologist was banned from acting as an expert witness. He had concluded that a father in a family law case was ‘psychopathic’ and that his child might need protection from him.
There was insufficient evidence to back up this conclusion. In the UK recently, a general practitioner was convicted of contempt of court. He had amended a report for a personal injuries case following a consultation with a solicitor, but without consulting the client.
In 2017, seven employees of a company called Autofocus Ltd were convicted of perjury after providing false evidence “on an industrial scale” concerning the price of replacement hire cars for motorists in road crashes.
Because the evidence of an expert can be crucial to the outcome of a case, a high standard of integrity is expected. To date in Ireland, there is no systematic punishment of experts who fail to comply with the expected standards.
However, the rules on expert evidence were amended in 2016, and it is likely that the courts will be more vigilant in monitoring such evidence in the future.
The High Court has already referred one orthopaedic surgeon to his professional body where he failed to refer to a subsequent accident when providing a report in a personal injuries claim.
This paper sets out the primary duties of an expert witness.
Duty to tell the truth
Every witness who gives oral evidence makes an oath or affirmation to tell the truth, the whole truth and nothing but the truth. When swearing an affidavit, the witness avers to his or her belief that the contents of the affidavit are correct.
The duty to tell the truth is the same for an expert witness as for a witness of primary fact. If anything, the expert witness is held to a higher standard, for two reasons: (a) an expert witness is normally paid for his or her work on the case; and (b) unlike most witnesses, an expert witness may – in certain circumstances – give evidence of his or her opinion concerning the matter in dispute.
Where, as is usual, an expert provides a report to one or both parties, this is expected to be the evidence that would be given if the matter proceeded to court. In the UK, an expert witness is now expect to make a ‘statement of truth’ in the report, which effectively elevates it to the status of an affidavit or statutory declaration.
In Ireland, the rules are not (yet) quite so exacting, but an expert should be wary of stating anything in a report that he or she would not stand over on oath. It is well established that, if the expert changes his or her mind on a matter of substance, this should be communicated forthwith to the other party or parties.
Duty of independence
Under no circumstances should an expert try to assist his or her own ‘side’ to win the case. It is long established that the duty of the expert is to the court rather than to the client, and that he or she owes no higher duty to the person paying the expert’s fees.
This is now established in Order 39, rule 57 of the Rules of the Superior Courts (as amended in 2016, which states: “(1) It is the duty of an expert to assist the court as to matters within his or her field of expertise. This duty overrides any obligation to any party paying the fee of the expert.” Furthermore, the expert’s report must now contain a statement acknowledging this duty.
It is not an exaggeration to say that this duty of independence is often misunderstood or ignored by expert witnesses. In almost every English speaking country, there are scores of judgments decrying the failure of experts to act in an independent manner.
Many high-profile miscarriages of justice have been caused or assisted by experts who failed to present the facts in a proper manner. To take one famous example, the Birmingham Six were convicted after the prosecution’s forensic scientist testified that he was “99% certain” that two of them had handled explosives.
In fact, the 'Griess test' he had used was merely a gateway test that showed the possibility that they had handled nitroglycerine. Even on the basis of scientific knowledge in the 1970s, it showed a mere possibility that they had handled the substance.
Duty to ascertain or investigate relevant facts
An expert witness should never rely solely on the facts as presented by the solicitor or client. While a solicitor might ask for a provisional view on a certain question based on assumed facts, this should be provided with a clear statement that it is not the expert’s final report on the subject.
The expert should ensure that he or she is presented with all of the relevant facts in order to present as full a picture as possible. In no way should the expert record or present the facts in a manner calculated to assist his or her own client.
Where an expert is responsible for investigation, there is a particular onus to measure, record and note the facts ‘on the ground’, as they may be relied upon by the other experts in the case.
The courts have set out in some detail the obligation on a pathologist carrying out a postmortem. A similar obligation must be said to apply to an engineer who is first on the scene after a road traffic accident, or an accident in the workplace.
Where investigating a defective building, measurements and photographs should be taken of anything that might be relevant. The expert should bear in mind the famous quotation from US Admiral Grace Hopper: “One accurate measurement is worth a thousand expert opinions.”
Duty to apply expertise in a professional and objective manner
The expert has an obligation to educate the decision maker on the relevant specialisation. It is not the expert who decides the case, but the decision maker (the judge, jury or arbitrator).
For this reason, the expert should not come to court with a personal theory of the case, but explain to the court what the consensus is on the topic among members of the profession.
If there is more than one theory, this should be outlined and explained. For this reason, the expert not only may, but should provide relevant quotations from textbooks or ‘learned treatises’, if they will assist the court in understanding the issue.
Duty to reach a reasoned and honestly held conclusion
Because experts are entitled to give opinion evidence to the court, it is sometimes believed that they have carte blanche to express personal opinions on the case. In fact, it is safer to say that their entitlement is to give a ‘reasoned conclusion’ to the court.
This conclusion should be solidly based on the facts of the case and their professional expertise. The ‘opinion’ should not be conjecture, but should be a reasoned inference on the facts before the court.
An unsupported statement by an expert witness has been described as ‘worthless’ by the UK Supreme Court in a case from 2016.
Duty to co-operate with the other parties and experts
It has long been established that the experts on either side of a case have an obligation to narrow down the issues between them. This is now formalised by the 2016 rules as regards non-personal injuries cases, but it may be taken that the existing obligation remains in relation to personal injuries cases.
Where the other parties put questions to an expert arising from a report, the expert is under a duty to answer them, provided that they are reasonable. Otherwise, the expert’s evidence may be excluded.
Following the exchange of reports, the expert may be required by the court to meet the experts representing other parties. They should attempt to narrow down the issues, and prepare a joint report explaining where they agree and where they differ.
Duty to comply with directions of the court
As well as being ordered to answer questions or attend meetings, the courts may require the experts to give evidence in novel ways.
In recent years, the courts of many countries have introduced a procedure known as ‘hot tubbing’ for expert witnesses (also called a ‘debate among experts’ or ‘concurrent evidence’). Instead of the experts giving evidence as part of each side’s case, they give evidence as part of a conference, chaired by the judge.
This is now provided for in the rules for non-personal injury cases in Ireland, but courts in all case have flexibility to hear issues using different ‘modes’ of trial.
Conclusion
It may reasonably be said that the duties set out above do not only apply to courtroom settings. If an expert attends an arbitration, conciliation, adjudication or mediation, he or she should uphold the highest standards of the profession and act in a strictly impartial manner.
(The expert witness – Part 1, by John Garrett, can be read here.)
Author: Mark Tottenham is a barrister and experienced mediator, and the co-author of A Guide to Expert Witness Evidence (Bloomsbury Professional, 2019), winner of the DSBA award for Practical Law Book of the Year, 2019. The duties outlined in this article are discussed in more detail in Chapter 3 of that volume. Contact 087 418 2894 and email: marktottenham@lawireland.ie