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Navigating legal or regulatory processes

Testifying: What it involves and how to do it effectively

A microphone in a courtroom

5 minutes

Published: June 2018 /
Revised: September 2022

The information in this article was correct at the time of publishing

Physicians may be asked to testify in a proceeding before a court, a regulatory authority (College), or another form of administrative tribunal (e.g. workplace safety and insurance board) in a variety of capacities, including as a treating physician, independent medical evaluator, or expert.

Treating physicians and fact witnesses

Treating physicians are most often called to give evidence in a proceeding as fact witnesses. As a fact witness, you will most likely be asked to testify about what you saw or heard while present at the event in question; your knowledge of the facts of the case; or your diagnosis, prognosis, and treatment of the patient if you are testifying as a treating physician.

Before appearing to testify, you may be asked to meet with a lawyer to discuss your evidence. Despite being asked or subpoenaed, you generally must have the patient's signed authorization or a court order before agreeing to provide any records or speak about your patient with a third party.

Independent medical evaluators

A physician who performed an independent medical evaluation (IME) may be asked to testify about the examination that they conducted.

While you may be required under privacy legislation to provide the examinee with a copy of the IME report, you are not obligated to speak with the examinee or their lawyer about the details of your testimony. If you are asked to speak with the examinee or their lawyer in advance of your testimony, you should first contact the party who requested the IME to ensure this discussion is appropriate.


Treating physicians are not typically considered expert witnesses. They are generally not required to comply with procedural requirements applicable to experts, including stating or signing a form acknowledging the expert’s duty to the court. That said, some treating physicians may be asked by counsel to comply with these rules. You are encouraged to clarify with counsel your role at trial, and also to express whether you agree to testify to matters beyond the scope of your direct clinical observations.

Whether you agree to act as an expert is your choice, based on factors such as whether you feel appropriately qualified to offer an opinion on the subject matter. While there is no obligation to act as an expert, many physicians feel a professional obligation to do so for either the plaintiff or defence. The CMPA endorses this view and encourages physicians to maintain their CMPA membership to be eligible to request assistance with medico-legal issues arising from their role as an expert.

Before accepting an expert retainer, you should verify that you do not have an actual or perceived conflict of interest. There are many circumstances where a conflict may arise, e.g. if you acted as the opposing party's treating physician; if you previously discussed the case with another party; or if you have a close personal or professional relationship with one of the parties. In instances where you feel you may have a conflict, voice your concerns as soon as possible with the lawyer or party retaining you.

Both the expert and the retaining lawyer should ensure that they each have a clear understanding of the relationship and their respective expectations. For example, the parameters of the opinion requested should be understood, as should the time commitment required to complete the opinion, any relevant deadlines, and any remuneration issues.

When acting as an expert, you should be cognizant that your role is to assist those involved in the judicial process to understand and decide issues based on often-complex medical evidence. Regardless of the nature of the retainer or who pays the account, experts have a duty to provide their evidence objectively, professionally, and fairly. Experts should not act as advocates for the party who retained them. In fact, the Rules of Court in some provinces require experts to certify that they understand that their duty is owed to the court and not to any particular party.

Judges have criticized certain medical experts who displayed clear partisan biases. This typically results in their evidence being rejected or given reduced weight. In the most egregious cases, it can even result in the court calling into question the expert's integrity.

Physicians should check with their regulatory authority (College) and medical association or federation, or other medical organizations (i.e. medical specialty organizations), for resources about acting as experts.

Physicians retained in legal proceedings as experts may not necessarily be asked to testify. For example, you may be retained to act as a consultant, often early in a case, to impart knowledge about the medicine and help assess the merits of the case. Even if you are retained with the intent of authoring a report and testifying, it is possible that you will ultimately not have to testify, as very few cases actually make it to a hearing.

The bottom line

Regardless of whether you are appearing as a treating physician, independent medical evaluator, or expert witness, the following suggestions can promote confidence and effectiveness when testifying:

  1. Be prepared

    • Review the report(s) you prepared, which may have been done several years before you actually testify. Your testimony should be based on the objective findings from your clinical record or report.
    • Review any relevant records or reports beforehand and be familiar with them. This includes the relevant literature that is cited in your report or in the reports of other experts.
    • Confirm with counsel the exact date, time, and place you will be required to attend to give evidence, and confirm what records or other material you should bring with you.
  2. Be aware of court etiquette

    • Arrive at the hearing at the assigned time, if not before, and be dressed in business attire.
    • When an exchange takes place between counsel and the court (or arbitrator, board, etc.), refrain from speaking until directed to continue.
    • At all times, remain objective, calm, and polite. Avoid being unnecessarily defensive. Do not let the tone or the nature of the question influence the manner in which you respond. If you disagree with a proposition being put to you, then make your disagreement known and briefly explain why.
  3. Communicate clearly

    • Ensure you understand what is being asked before you attempt to answer. Do not hesitate to ask that the question be repeated or rephrased. If you do not know the answer, simply say so. Take the necessary time to reflect upon your answer.
    • Speak clearly, slowly, and loudly enough so that all can hear you. If it is helpful, refer to records or diagrams. Use plain language and avoid overly complex medical jargon. Where medical terms are useful or unavoidable, explain them clearly.
    • Answer questions honestly and completely, yet succinctly. Avoid exaggerating, embellishing, or discussing matters beyond the parameters of the question you have been asked.

DISCLAIMER: The information contained in this learning material is for general educational purposes only and is not intended to provide specific professional medical or legal advice, nor to constitute a "standard of care" for Canadian healthcare professionals. The use of CMPA learning resources is subject to the foregoing as well as the CMPA's Terms of Use.