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.
An Alberta court found that an urgent C-section taking 101 minutes fell below the standard of care, that two physicians’ combined 50 minutes of unnecessary delay was not a defensible judgment call, and that the delay caused a child’s cerebral palsy. A look at the timeliness standard, the causation reasoning, and why this Alberta decision is persuasive, not binding, in Ontario.
How surgical negligence claims succeed or fail. A 2026 OTLA Spring Conference paper on never events and recognized complication cases.
Yes, you can sue for medical malpractice in Ontario. The harder question is whether you should. After two decades of these cases, the candid advice for many prospective clients is to think very carefully before going forward, and in some cases, not to go forward at all.
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.
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