InfoLAW: Expert Witness

At some point in your nursing career, you may be asked to act as an expert witness in a legal proceeding. This can provide a unique opportunity to interact with the legal system. In this infoLAW, we unpack what it means to be a nurse expert witness.

What is an expert witness?

An expert witness is someone who, because of their education, experience, or a combination of both, has a high level of knowledge and can provide a testimony that is based on sound scientific evidence.¹ Expert witnesses are generally retained to provide this knowledge to inquests, hearings, and trials. As an expert witness, you should generally be prepared to provide a well-constructed opinion based on the evidence provided to you, and to be able to justify that opinion.²

When a nurse is asked to be an expert witness, they are usually asked to provide expert knowledge in medical malpractice or negligence cases. In these cases, nurses generally provide expert testimony to establish what the reasonable standard would be given the facts of the case, or to provide an expert opinion on a hypothetical question related to the case.

Unlike a fact witness, an expert witness cannot testify as to what happened during the incident because they were not present when the incident took place. An expert witness must have some specialized knowledge and experience in order to assist the court to understand the evidence and should not offer opinion evidence on matters beyond their established expertise.³

What can you expect as an expert witness?

Fees and Expenses
As an expert, you are entitled to reasonable compensation for your services and expenses. Before agreeing to take on the role of expert witness, it may be prudent to speak to the lawyer who is seeking to retain your services and request a written contract outlining expectations, fees and what they cover, and reimbursement for expenses. Your hours billed should include the time spent in telephone or in-person consultations with the lawyer, reviewing documents and preparing reports, travelling (plus expenses) and appearing in court. You should also include a term in the contract that requires payment of your account upon invoicing.

Preparing to Testify
When preparing for your testimony, you may wish to review all relevant documentation that should be provided to you prior to your appearance. This documentation may include patient care records, statements given before the proceeding (such as the statement of claim, statements of defence, and transcripts from the examination for discovery), policies and procedures, letters, and memos. It may be beneficial while you are preparing your testimony to proceed through the review of a medical case just as it unfolded clinically in order to avoid hindsight bias, which is a bias that can occur where one believes an event was more likely after they have found out the outcome.⁴ While forming your opinion, it may be prudent to provide references to publications on best practices at the time of the incident, standards of practice, policies, and other relevant material.

Providing your Testimony
Once you are called to provide your testimony, you will be sworn in by the court, which means you will promise to tell the court the truth. You will then be asked by the lawyer who asked for your expert testimony to present your credentials so that the court may accept that you are qualified to act as an expert witness. This generally takes place in what is referred to as a “voir dire,” which is used when a court needs to confirm the competency of witnesses to testify. During the voir dire, the court will have to be satisfied about the following four factors in order to hear the expert’s opinion evidence:

1. Necessity in assisting the court; expert opinion evidence is only necessary if it provides information outside the experience and knowledge of a judge or jury.
2. Relevance to the matter at issue.
3. Qualifications.
4. The absence of an exclusionary rule of evidence.⁵

After the judge has qualified you as an expert, you will first be questioned by the lawyer who has retained your services and then cross-examined by the opposing counsel. Following cross-examination, the lawyer who retained your services may wish to re-examine you and ask you further questions.

When answering questions, it is important to:

• Direct your responses to the jury, or to the judge if there is no jury.
• Answer questions to the best of your ability, clearly and concisely. If you are asked questions that you do not know the answer to, it is best to say so to avoid providing any information that may be incorrect. Similarly, it is generally advisable to avoid volunteering information that is outside the scope of the question or that was not asked of you.
• Use everyday language to answer questions where possible. When you must use medical jargon, you consider providing an example or definition to ensure that your answer is understood.

The following suggestions will assist you when providing an expert testimony:

• Understand the legal meaning of “standard of care”.⁶
• Be prepared to offer opinions about whether a particular type of conduct or treatment was appropriate (given the circumstances as you interpret them) and in accordance with evidence-based practice.
• If you are asked questions about matters outside the scope of nursing, inform the court that this is outside your field of expertise.
• When you are asked to provide a “yes” or “no” response to questions that cannot be answered in this manner, tell the lawyer that you cannot answer the question in that manner, but that an explanation is required. The judge will usually allow you an opportunity to explain.
• Avoid “taking sides” when giving your expert opinion or promoting the position of one party over the other. This may reduce your credibility as an independent professional.
• Do not contradict yourself either within testimony or with anything that you have written or said beforehand unless you are able to explain why you are now giving a different opinion.
• Avoid discussions with other witnesses outside the courtroom and politely refrain from giving statements to the press. If a recess is given during your testimony, the judge will direct you to not discuss your testimony with anyone else.

Summary

Acting as an expert witness is a unique experience that can be rewarding. As a nurse, you are under no obligation to act as an expert witness in any legal proceeding. If you do agree to appear as a witness, proper preparation will go a long way to help you be a more effective witness.

CNPS beneficiaries can contact CNPS at 1-800-267-3390 to speak with a member of CNPS legal counsel. All calls are confidential.

1. Emily Phillips & Sharon W Stark, “Stepping up to be an expert witness” (2013) 38:10 The Nurse Practitioner.
2. Roy G Beran, “The role of the expert witness in the adversarial legal system” (2009) 17 Journal of Law and Medicine.
3. Elaine Borg, “The Nurse as an Expert Witness,” Canadian Nurse 100, 6 (June 2004): 38-39.
4. Lisa A Miller, “Offering Expert Testimony” (2016) 30:2 The Journal of Perinatal and Neonatal Nursing 93–94; Neal J Roese & Kathleen D Vohs, “Hindsight Bias” (2012) 7:5 Perspect Psychol Sci 411–426.
5. R v. Mohan [1994] 2 S.C.R. 9
6. Lisa A Miller, “Offering Expert Testimony” (2016) 30:2 The Journal of Perinatal and Neonatal Nursing 93–94.

March 2006, Revised July 2024

THIS PUBLICATION IS FOR INFORMATION PURPOSES ONLY. NOTHING IN THIS PUBLICATION SHOULD BE CONSTRUED AS LEGAL ADVICE FROM ANY LAWYER, CONTRIBUTOR OR THE CNPS. READERS SHOULD CONSULT LEGAL COUNSEL FOR SPECIFIC ADVICE.