Expert evidence is the engine of medical malpractice litigation. Because judges and juries are not expected to know what a reasonable physician, nurse, or other regulated health professional would have done in a given clinical situation, qualified experts are needed to define the standard of care, explain the mechanism of injury, and address causation. In most Ontario medical malpractice trials, expert evidence is the difference between success and failure.
Expert reports and testimony in the Ontario Superior Court are governed by Rule 53.03 of the Rules of Civil Procedure, which sets out service deadlines, content requirements, and the expert’s duty to the court. The admissibility framework was refined by the Supreme Court of Canada in White Burgess Langille Inman v Abbott and Haliburton Co, 2015 SCC 23, [2015] 2 SCR 182, which clarified the role of expert independence and impartiality at the threshold stage.
Posts tagged Expert Evidence analyze how Ontario courts have ruled on the qualifications of medical experts, the scope of permissible opinion, challenges to admissibility, and the weight given to competing expert opinions at trial.
In Forget v Gibb, 2026 ONSC 626, the Ontario court dismissed a surgical negligence claim and delivered a sharp critique of the plaintiff’s expert.
The Supreme Court of British Columbia dismisses a prophylactic laparoscopic hysterectomy bowel injury claim where the plaintiff led no expert evidence. Informed consent, the modified objective test, and the indispensability of expert evidence.
Dr. Bailey admitted that her management of labour was negligent and that it caused a hypoxic brain injury at birth. The plaintiffs still lost, because they could not prove that the brain injury caused the child’s lasting impairments. JB v Bailey is an Alberta decision, persuasive only in Ontario, but it is a clear reminder that admitted negligence and admitted injury are not the same as proven causation.
How plaintiff PI firms build long-term strategy and growth. From the 2026 LIF webinar Defining a Winning Business Strategy for Your PI Firm.
Most medical malpractice consultations in Ontario don’t result in lawsuits. An honest look at the four barriers that shape case evaluation in this province.
Ontario court dismisses orthopaedic malpractice claim after finding hip replacement subsidence was osteointegration failure, a recognized complication, not negligence.
How plaintiff-side PI practice works as a business: case screening, partnerships, and resourcing. From a 2024 Legal Innovation Forum panel.
How to cross-examine the defence expert and advance your case theory. From the 2024 OBA Anatomy of a Trial continuing professional development program.
Composite card pairing the Medico-Legal Society of Toronto crest with the title Causation in Systemic Medical Negligence, on Paul Cahill’s navy brand panel.
A widow’s appeal in a death after delayed embolization for a lingual artery pseudoaneurysm. The BC Court of Appeal affirmed dismissal on the standard of care.
A claim alleging that psychiatrists failed to disclose dose increases during a course of ECT was dismissed mid-trial for absence of expert evidence. The BC Court of Appeal affirmed.
A self-represented plaintiff’s negligence and informed consent claims against an OBGYN were dismissed on summary judgment for lack of expert evidence.
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