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Medical Expert: Reports and Testimony

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Approved by Council: December 2012

Companion Resource: Advice to the Profession


Policies of the College of Physicians and Surgeons of Ontario (the “College”) set out expectations for the professional conduct of physicians practising in Ontario. Together with the Practice Guide and relevant legislation and case law, they will be used by the College and its Committees when considering physician practice or conduct.

Within policies, the terms ‘must’ and ‘advised’ are used to articulate the College’s expectations. When ‘advised’ is used, it indicates that physicians can use reasonable discretion when applying this expectation to practice.



Medical Expert1: medical experts assist those involved in a legal proceeding to understand the medical evidence. A medical expert is typically requested to interpret and/or provide his or her opinion on clinical, scientific or technical issues that normally lie outside the knowledge and experience of the average person. Physicians acting as experts are different from witnesses of fact (testifying about events that they themselves have observed). Acting as a medical expert may involve providing a written and/or oral expert opinion.



  1. When acting as medical experts, physicians must provide objective and impartial opinions on matters that fall within their scope of expertise
  2. Physicians are advised to obtain legal advice if they are unsure of their obligations in specific circumstances.

Accepting a Request to Act as a Medical Expert

Obligation to Act as a Medical Expert

  1. Physicians do not have an obligation to act as medical experts. Before agreeing to act as an expert, physicians must consider, among other things, whether they have the requisite expertise the matter requires, and whether any actual or potential conflicts of interest exist between them and the parties involved.3
  2. Where physicians have any doubt as to whether acting as a medical expert is prudent, they are advised to obtain legal advice before proceeding.

Potential Conflicts of Interest

  1. To manage conflicts of interest effectively, physicians are advised to disclose the existence of the potential conflict before accepting requests to act as medical experts.
  2. When disclosing potential conflicts of interest involving a patient or former patient, physicians must not disclose any personal health information about that patient without their consent, unless permitted or required by law.

Communication Regarding the Physician’s Role

  1. Where the physician finds it necessary to interact directly with the individual4 who is the subject of the legal proceeding, they must be clear about the nature of their role as medical expert.
  2. Physicians must explain that their role is not to treat the individual, but to provide objective and impartial opinions to assist the adjudicative body (e.g., court) involved in the legal proceeding and that:
    1. their role may involve obtaining, using and disclosing personal health information about the individual to the person instructing them (e.g., lawyer), in the context of providing an expert opinion;
    2. this information or expert opinion may also be shared with others involved in the legal proceeding, if the lawyer decides to use it in the proceedings; and
    3. where required, consent for obtaining, using and disclosing personal health information will be obtained.
  3. Physicians are also advised to convey that the final outcome of the legal proceeding is not determined by them, but rather by the adjudicative body involved in the legal proceeding.


  1. Where physicians are asked to review the personal health information of a specific individual, they must ensure that proper consent has been obtained to use to use and disclose that information in their report and/or testimony, unless they are permitted or required by law to use and disclose that information.6
  2. If physicians are asked to conduct a medical examination on a specific individual, consent for the examination must be obtained.
  3. Physicians are advised to err on the side of caution and obtain legal advice if they are uncertain about their consent obligations for any reason.


  1. Physicians must discuss fees for acting as medical experts with those who are instructing them.
  2. Physicians must only charge fees that are reasonable for acting as medical experts.7,8

Presence of Observers and Audio/ Video Recording

  1. If physicians are conducting a medical examination for the purposes of a legal proceeding and one or more parties wish to have an observer present and/or record the examination, physicians are advised to discuss the matter with the person instructing them, as specific rules may apply.9


  1. Before providing expert opinions, physicians must ensure that they understand what they are being asked to do, and specifically, what questions they are being asked to answer.
  2. If the instructions are unclear, inadequate or conflicting, physicians must seek clarification from those instructing them.

Acting as a Medical Expert

Objectivity & Impartiality

When physicians provide expert opinions, their duty to the adjudicative body prevails over any obligation to the person who is instructing or paying them.

  1. Physicians acting as medical experts must:
    1. assist the adjudicative body by providing objective and impartial opinions;10
    2. be honest, objective and impartial;
    3. provide opinions that are reasonable, fair, balanced, and substantiated by fact, scientific evidence11 or experience, and sound clinical judgment;
    4. not advocate for any party involved in the legal proceeding;
    5. not allow personal bias to prejudice the expert opinions they give;
    6. not provide comments that are unrelated to the expert opinion; and
    7. not make any unprofessional comments or criticisms regarding the other experts or individuals involved in the legal proceeding.12

Scope of Expertise

  1. Physicians must accurately represent their scope of expertise and restrict their statements to areas in which they have expertise.
  2. If a particular question or issue falls outside the physician’s area of expertise, the physician must clearly state this and decline to answer.13

Comprehensiveness & Accuracy

  1. Physicians must provide expert opinions that are comprehensive and accurate.14
  2. Physicians must ensure that all relevant information has been considered,15 and that the information they rely on to form their expert opinions is accurate.16
  3. Physicians must clearly express when they do not have enough information to arrive at a conclusion on a particular point, or where their opinions are otherwise qualified.
  4. If physicians change their opinions, they must communicate this to the person instructing them in a timely manner.


  1. Physicians must:
    1. be transparent about the instructions they have been given, the process they use to form their opinions, and the information they rely upon in doing so17;
    2. be clear about what has been requested of them (e.g., the questions they were asked to answer);
    3. have a clear and comprehensible reasoning process, from the underlying data to the ultimate opinion; and
    4. state all factual assumptions on which the expert opinions are based, and describe any research they conducted and any documents or records they relied upon in forming their opinions.


  1. To allow for optimal clarity, physicians must use language and terminology that will be readily understood by lay persons. As part of this, physicians must explain any abbreviations and medical or other technical terminology used.


  1. Physicians must provide written reports and/or testimony without unreasonable delay.18

Final Considerations

Suspicious Findings

When examining an individual or reviewing the personal health information of an individual whom they are not treating, a physician may become aware of a suspicious finding where it is unclear whether it has been previously identified, including an unexpected significant clinical finding or condition that raises serious concerns or may require essential intervention.19 Given that the physician is conducting the examination or review in their role as medical expert, and not as treating physician, they may have different responsibilities concerning the disclosure of the suspicious finding to the individual, as specific legal obligations may apply.

  1. In general, physicians who become aware of a suspicious finding must use their professional judgment to determine whether to seek legal advice, based on the circumstances of the particular case.
    1. Where the suspicious finding does not suggest that the individual is at immediate risk of harm and that urgent medical intervention is required, physicians must seek independent legal advice regarding the disclosure of the suspicious finding to the individual.
    2. Where the suspicious finding suggests the individual is at imminent risk of significant harm and immediate medical care is required, physicians must exercise their professional judgment to determine whether the patient’s current clinical status is urgent enough to warrant immediate disclosure to the individual.
      1. When physicians notify an individual of suspicious findings, physicians are advised to emphasize the importance of obtaining timely medical attention and to seek the individual’s consent to share these findings with his or her primary care provider.
      2. When consent is obtained, physicians are advised to convey the findings in written form to the primary care provider to facilitate appropriate medical follow-up.
  2. If the suspicious finding is disclosed, physicians must only provide clinical information that is directly relevant to the finding.

Records Retention & Access

Generally speaking, physicians are required to retain records20 and provide access to that information with appropriate consent, where applicable.21 However, when acting as medical experts, their obligations may depend on the rules governing the legal proceeding and the specific circumstances of the case.

  1. Physicians are advised to familiarize themselves with the legal requirements applicable to the specific context in which they are providing their expert opinions and/or obtain independent legal advice regarding their obligations to retain records and/or provide access to the information.


1. “Expert witness” is another term commonly used to describe a physician who acts as an expert.

2. This policy is not an exhaustive catalogue of the totality of requirements that may apply to experts who write reports and/or provide testimony. Specific requirements can include, but are not limited to, those found in the Rules of Civil Procedure or specific rules for various legal contexts or in the principles of solicitor-client and litigation privilege.

3. For more information on potential conflicts of interest, please see the Advice document.

4. For the purposes of the provisions of the Health Professions Procedural Code, Schedule 2 of the Regulated Health Professions Act, 1991, S.O. 1991, c.18, concerning sexual abuse of a patient, the College will consider individuals to be patients.

5. For more information on consent obligations, see the Advice document.

6. Where personal health information is reviewed or obtained, physicians may only collect, use and disclose personal health information with the consent of the individual to whom the personal health information relates, or as permitted or required by law. Consent requirements for the disclosure of personal health information are contained in the Personal Health Information Protection Act, 2004, S.O. 2004, c.3, Schedule A (hereinafter PHIPA), and/or the Personal Information Protection and Electronic Documents Act, S.C. 2000, c.5

7. In addition to any attendance fees that may be set for specific proceedings, (for example, if a physician has been summoned to testify in court as a witness/medical expert, the daily attendance is set in the rules that regulate the procedures of that particular trial or hearing. This can include the Rules of Civil Procedure, the Family Law Rules, etc.) some organizations (e.g., the CMPA) have set fees for physicians who are retained as medical experts by that organization. Physicians can refer to the Ontario Medical Association Physician’s Guide to Uninsured Services for guidelines, and/or other guidelines prepared by relevant organizations (e.g., Canadian Society of Medical Evaluators), as appropriate. For more information on fees see the Advice document.

8. Under Sections 1(1), paragraph 21 and 1(1), paragraph 22 of Professional Misconduct, O. Reg., 856/93, enacted under the Medicine Act, 1991, S.O. 1991, c. 30, it is an act of professional misconduct to charge a fee that is excessive in relation to the services provided, and to charge more than the current recommended fees in the Ontario Medical Association Guide without first notifying the patient of the excess amount that will be charged.

9. For example, for court-ordered examinations, Rules of Civil Procedure, O. Reg., 438/08, enacted under the Courts of Justice Act, R.S.O. 1990, c. C.43 (hereinafter Courts of Justice Act, Rules of Civil Procedure). Rule 33.05 states: “No person other than the person being examined, the examining health practitioner and such assistants as the practitioner requires for the purpose of the examination shall be present at the examination unless the court orders otherwise.” 

10. See for example the duties of experts set out in Section 4.1.01 of the Courts of Justice Act, Rules of Civil Procedure.

11. Scientific evidence includes scientific theory and technique. The trier of fact (i.e., judge, jury, etc.) must determine the reliability of the scientific evidence that the expert’s opinion relies upon.

12. For additional information on professionalism, refer to the College’s Practice Guide.

13. Canadian Medical Protective Association, Effective Testifying (CMPA, 2008).

14. Section 1(1), paragraph 18 of the Medicine Act, Professional Misconduct Regulation.

15. As articulated in the College’s Third Party Reports policy, physicians must ensure that they have obtained and reviewed all available information that could impact their findings, opinion and/or recommendation.

16. As articulated in the Third Party Reports policy, if physicians rely on information which they cannot substantiate independently, physicians must note the source of the information and the fact that it has not been independently confirmed.

17. See for example Section 53.03(2.1) of the Courts of Justice Act, Rules of Civil Procedure.

18. Section 1(1), paragraph 17 of the Medicine Act, Professional Misconduct Regulation.

19. This includes, but is not limited to, undiagnosed conditions and conditions for which immediate diagnostic intervention is required.

20. Sections 18 and 19 of the General, O. Reg., 114/94, enacted under the Medicine Act, 1991, S.O. 1991, c. 30.

21. For information on medical record-keeping requirements, refer to the College’s Medical Records policy. For more information on the disclosure of personal health information, see PHIPA.