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How do you prove a medical malpractice claim?

by Chris Wullum

There are many different types of medical malpractice claims, but no matter the type of claim, there are three essential components that must be established that are common to all:

  1. Did the medical professional meet the standard of care expected of them in the circumstances?  This is often referred to as whether the medical professional was negligent in the care provided. 
  2. If the person did not meet the standard of care expected and was negligent, did this cause actual harm or injury to the patient?  This is referred to in the legal realm as causation.
  3. Lastly, what was the actual harm or injury caused to the patient.  It is necessary to establish what the damages are for the claim.

Standard of Care or Negligence

In a medical malpractice lawsuit, it is not enough to show that there was a bad outcome as a result of medical care or treatment.  Not every mistake made by a medical professional constitutes negligence and is the basis for a successful lawsuit.  What must be established is that the care, treatment or decisions made fell below the acceptable standard of care expected of a similarly trained medical practitioner in the circumstances.

What a judge deciding the issue must determine is whether the error committed by the health-care professional is one that no similarly qualified health-care provider would have reasonably made in those circumstances.  The question a judge must consider is what  a reasonable and prudent medical professional with similar qualifications would have done.

Standard of care is almost always established by reference to expert evidence provided by an expert in the particular health care field of the medical professional that provided the care in question.  In other words, if the claim is against a nurse, an expert in nursing standards and practice would need to provide a report and evidence as to what the standard of care would be in the particular circumstances of the case, and whether the particular nurse in question fell below that standard of care in his or her treatment to the  patient. 

When it comes to the medical world, there are of course many different areas of health care and types of professionals that provide health care with different levels of specialty training.  There are physicians that treat patients for general concerns, such as a family doctor, while there are physician specialists in medical care such as radiologists that interpret x-rays, CT scans and MRIs, or oncologists that specifically treat various cancers.  For these reasons it is always necessary to determine the specific qualifications and practice area of the medical professional who may be the subject of a malpractice claim as it will be important to seek an expert that has experience and training in the subject matter of the medical professional involved in the care and treatment in question.

Standard of care can also be dependent on the where the treatment or care is being provided.  In other words, the standard of care expected at a smaller rural or community hospital may be different than a large tertiary hospital in a major urban setting.

As well, standard of care can be impacted by the severity, acuity or risk involved in the health care situation that the patient presents with.  Some situations may require greater vigilance, monitoring or testing depending on the risk of harm involved in the situation.


If you are able to establish that the medical professional’s conduct fell below the standard of care expected in the circumstances, it is still necessary to prove that the conduct caused harm or injury to the patient.  Generally, to prove causation in a legal case in Canada, you must be able to demonstrate that you would not have sustained injury or harm but for the substandard care.  This again is usually done through expert or other medical evidence to prove the connection between matters or events.

Causation does not have to be proven with medical certainty, as that can be a significantly difficult hurdle to meet, especially in dealing with medical probabilities.  However, a person bringing a medical malpractice claim must establish proof on a balance of probabilities, meaning that it is more likely than not that the injuries or harm were caused by the substandard care or treatment. 

Causation can be a complex area in medical malpractice cases.  There has also been some unique exceptions to the usual but for test described above, in cases where it may be impossible to prove causation in the normal course or where an adverse inference can be drawn against the opposing parties on the issue of causation.

Many malpractice cases have been lost on the issue of causation even where they have successfully proven a breach of the standard of care and therefore must always be carefully assessed for any potential case.


If you can establish and prove the above two issues to the satisfaction of the Court, you will usually have been able to show that the patient has suffered harm or injury from the events which would constitute damages in a medical malpractice case.  Damages are the value or economic compensation for your claim.

Damages typically include compensation for pain and suffering (typically referred to as general damages), loss of income or an impairment to earn an income, the costs for any care required as a result of the injuries, and other out of pocket expenses. 

If you would like more information about a potential medical malpractice scenario, please feel free to contact us for a free confidential consultation.