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Clinical practice guidelines: What is their role in legal proceedings?

An article for physicians by physicians
Originally published September 2011

The CMPA is often asked by its members about the potential medico-legal implications of clinical practice guidelines. While the Association neither creates nor endorses clinical practice guidelines (CPGs), it can describe how the courts consider a guideline when determining whether the standard of care was met.

The bottom line

  • The courts may hear expert evidence of a clinical practice guideline that was available at the time and purportedly served as evidence of the standard of care. The weight that will be given to the CPG depends on the testimony of experts as to its credibility, validity, applicability, and degree of acceptance at the time. The CPG alone does not constitute de facto evidence of the standard of care without supporting evidence from an expert.
  • Evidence concerning the dissemination of the clinical practice guideline among the profession may be one of the factors the courts will consider in deciding the weight to be given to a guideline. Courts have acknowledged that there may be a lag between the time a CPG is published and when it is accepted into clinical practice.
  • Even an authoritative CPG may not be found to be determinative of a standard of care. A court may limit the application of the CPG based on expert evidence about whether and how it was being applied by practitioners at the time. In some cases, the standard of care of a "prudent colleague" may hold more weight in court.
  • It is prudent for physicians to be aware of authoritative clinical practice guidelines relevant to their practices. If a clinical decision may be perceived as being contrary to a recognized and accepted CPG, a physician, where appropriate, may consider the following steps: consult with a colleague or relevant specialist, discuss reasonable treatment options with the patient, and document the patient's consent for the chosen treatment.
  • If deviating from an established CPG, physicians should consider documenting the rationale for doing so, as well as any discussions with the patient about such variance. Such steps may assist in defending the care should it come into question in the future.

Defining the standard of care

In legal proceedings where there is an allegation of clinical negligence, it is the court's role to determine whether the care provided by the physician fell below the accepted standard of care at the relevant time.

The standard of care expected of a physician is often described by reference to the following extract from a case decided in 1956:
Every medical practitioner must bring to his task a reasonable degree of skill and knowledge and must exercise a reasonable degree of care. He is bound to exercise that degree of care and skill which could reasonably be expected of a normal, prudent practitioner of the same experience and standing, and if he holds himself out as a specialist, a higher degree of skill is required of him than of one who does not profess to be so qualified by special training and ability.
— Sylvester v. Crits et al, [1956] S.C.R. 991

More recent cases have further clarified the standard of care. Courts will not evaluate a physician's decisions against a standard of perfection or infallibility. Negative outcomes are to be expected and must be distinguished from acts of negligence.1

Both sides in a court case, the plaintiff (the patient or the patient's family) and the defence, will introduce evidence of the care and skill that a normal, prudent practitioner of the same experience and standing would have provided in a similar situation. As part of that evidence, both sides can introduce medical experts, who may refer to CPGs as representative of the standard of care at the relevant time.

Courts rely on medical experts, who are professionals of similar skill and experience as the defendant physician, to give an opinion on the medical standards at the time the care was provided. An expert can give evidence on a CPG and state why it may or may not represent the standard of care in the particular circumstances, or whether there were any other relevant CPGs available at the time.2

While a court may consider the testimony of medical experts, there are limitations. An expert provides only one perspective based on that individual's professional experience, including his or her practice, and knowledge of the relevant literature at the time.3 Courts have also recognized that there may be differences in practice and adopting a respected school of thought that is different than one's colleagues does not necessarily mean a physician's care was negligent. In addition, a court will take into account that an expert's opinion is being provided after the clinical outcome is known, which may affect how objectively the clinical care can be viewed.4


The relevancy of a clinical practice guideline

The role of clinical practice guidelines in a legal proceeding can be summarized as follows:

Guidelines are not equivalent to, and should be distinguished from, the legal standard of care to be applied by the Court…. (W)hile "practice guidelines" may be generally respected and therefore relevant considerations in the Court's assessment of the standard of care, they are not intended to, and do not determine the legal standard of care that the Court will impose on a medical professional, especially where there is expert opinion evidence on the standard of care with reference to the facts of the particular case.
— Keith v. Abraham, 2011 ONSC 2 (CanLII)

A court will scrutinize an expert's evidence of a clinical practice guideline to determine if it is relevant, taking various factors into account including:

  • how applicable it is to the case
  • whether the CPG was relatively free of controversy and reflected in the common practices of the medical community at the time the care was provided
  • whether there were any other guidelines or literature addressing the same issue
  • the language in which the guideline is expressed
  • the authors and the process used to draft the guideline5

The most authoritative CPGs are typically based on evidence from randomized, controlled trials. Less reliable are those that are a collection of clinical opinion where evidence is absent or contradictory.6


Notwithstanding a medical expert's evidence that a clinical practice guideline was authoritative and widely accepted at the time, courts must still decide whether it is reliable evidence of the standard of care at the relevant time. Regardless of whether the care was in accordance with a CPG, a court will inquire whether the practice was applied prudently.7 In other words, when deciding whether a physician's care was negligent, a court will weigh the evidence and ascertain the standard of care that a similarly qualified physician was expected to follow at the time.


  1. Moffett, P., Moore, G., "The standard of care: Legal history and definitions, The bad and good news," Western Journal of Emergency Medicine (2011) Vol. 12, no. 1 p109-112.
  2. Ibid. p109-112.
  3. McDonagh, R.J., Lavis, J.N., Sharpe, G., "Clinical practice guidelines as explicit standards of care: Medico-legal considerations," Annals RCPSC (2002) Vol. 35, no. 1 p9.
  4. Ibid. p9.
  5. Jutras, D., "Clinical practice guidelines as legal norms," Canadian Medical Association Journal (1993) Vol. 148, no. 6 p905.
  6. Ibid. p905.
  7. Ibid. p905.

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.