All about the journey?: Circumstantial evidence and standard of care

by Elizabeth Bowker, Michael Connolly | Oct 20, 2020

It can be difficult for litigants and the Courts to figure out the complex relationship between the standard of care analysis and the nature of the injury or damage suffered by the plaintiff.

There is no duty to “Be Perfect”:  the standard of care analysis does not impose an absolute duty of perfection.[1]  In cases of professional negligence, the standard of care analysis compares the conduct of the defendant to that of a reasonably prudent and diligent fellow professional in the same circumstances.[2] Accordingly, a trial judge must articulate a framework for what constitutes reasonable care in the circumstances and what measures must be taken by the defendant to exercise such reasonable care.

Generally a trier of fact should first determine whether the standard of care was breached, and only then go on to address the “but for” causation.[3] However, in certain instances, the trier of fact may first make inferences about the breach of the standard of care based on circumstantial evidence of injury.

Two recent decisions from the Ontario Court of Appeal illustrate this nuanced relationship between circumstantial evidence of harm and findings of breaches of standard of care, as well as the limitations of relying too heavily on the nature of an injury to support claims of negligence.

Armstrong v. Royal Victoria Hospital (2019 ONCA 963)

The plaintiff developed severe left flank pain after undergoing laparoscopic colectomy surgery. Subsequent examination revealed an 8-10cm blockage in the left ureter (a tube that carries urine from the left kidney to the bladder). The damage was significant and lead to the removal of the plaintiff’s left kidney.

The laparoscopic colectomy surgery involved use of a LigaSure – a surgical instrument that severs and fuses tissue by way of electrical current. The LigaSure can cause collateral injury to tissue in the immediate vicinity, as the thermal energy can spread within 2 millimetres of the device.

The issue in this case was whether the general surgeon met the standard of care simply by following the normal steps of the procedure, or whether the existence of the injury was evidence that the standard of care had been breached. The expert witnesses agreed regarding the appropriate steps of conducting a laparoscopic colectomy, the rarity of the injury, as well as that a reasonably prudent surgeon would take steps to avoid such injury by identifying and protecting the ureter.

The trial judge held that the defendant general surgeon had breached the standard of care by bringing the LigaSure within 1-2 millimetres of the plaintiff’s ureter, thereby causing scar tissue and the eventual ureter blockage. He accepted that the standard of care for a general surgeon is to identify, protect, and avoid direct contract with or close proximity to the ureter when using the LigaSure.[4] Based on expert testimony, “close proximity to” means within one to two millimetres from the ureter.[5] The trial judge held that the defendant surgeon must have brought the LigaSure within one to two millimetres of the ureter based on the nature of the obstruction and subsequent injury. On cross-examination, the defendant admitted that the ureter was not always in camera view during the procedure.[6] Importantly, the trial judge found that the defendant breached the standard of care, even though he took appropriate measures to identify and protect the ureter.

The Ontario Court of Appeal overturned the trial judge’s findings in a 2-1 split decision. Writing for the majority, Justice Paciocco held the trial judge erred by measuring the standard of care based on the goal a prudent surgeon would have when conducting the procedure, rather than the means a prudent surgeon would use to attain that goal. Standards of care are to be measured by the behaviour that a relevant prudent person would undertake, rather than whether the person achieved the desired results.[7]

In this case, Justice Paciocco held the trial judge ought to have restricted his standard of care analysis to whether the defendant followed the appropriate steps of the laparoscopic colectomy, without consideration of circumstantial evidence.[8] The trial judge accepted that a prudent surgeon should identify, protect, and avoid direct contract with or close proximity to the ureter when using the LigaSure. Accordingly, his findings that the defendant took such measures should have ended the analysis. The measures taken by the surgeon to keep the LigaSure a safe distance away from the ureter are among the steps of the procedure, whereas absolutely avoiding all contact with or proximity to the ureter was one of the procedure’s goals.[9] In this case, assessing the surgeon’s standard of care based on the goal of the procedure would amount to strict or absolute liability.[10]

By placing undue weight on whether the desired result is achieved, a trier of fact may improperly conflate standard of care with causation.[11] Justice Paciocco held that goals and results of procedures may be relevant considerations where the negligent act is the only explanation for why they were not attained.[12] In such instances, a trial judge is obliged to consider and rule out non-negligent causes prior to assessing the standard of care.[13] No such finding was made in this case.[14]

Courts may only consider circumstantial evidence about the loss prior to resolving the standard of care analysis in cases where the nature of the injury is directly related to the alleged conduct of the defendant.[15] Circumstantial evidence should not be considered where the type or kind of injury is not directly related to alleged manner of the breach. In every instance, the “but for” causation analysis must occur after the standard of care analysis.[16]

In dissent, Justice van Rensburg would have upheld the trial judge’s findings. She was not convinced that the trial judge held the defendant surgeon to a standard of perfection nor that he based his standard of care findings on the goals of the procedure. The defendant and medical experts consistently discussed ensuring that the LigaSure be kept away from the ureter among the steps a prudent surgeon takes when performing a laparoscopic colectomy. Therefore, it was open to the trial judge to make such findings.

Justice van Rensburg believed the trial judge never concluded that the defendant complied with all reasonable steps of the procedure. He only found that the defendant took certain steps to identify and protect the ureter. For example, the defendant admitted on cross-examination that the ureter was not always in camera view during the procedure.[17]

Importantly, Justice van Rensburg disagreed with Justice Paciocco’s conclusions regarding when circumstantial evidence may inform the standard of care analysis. She held that the Court is not obligated to consider potential non-negligent causes where there is no evidentiary foundation to do so.[18] In this case, there was no evidence or expert opinion that a surgeon exercising reasonably care could not have stayed two millimetres away from the ureter in certain circumstances during the procedure. The defendant never testified that he tried to stay away from the ureter but was unable to do so. In fact, he believed that he never brought the LigaSure in close proximity to the ureter.[19]

Accordingly, the trial judge did not conflate the standard of care with factual causation. Although Justice van Rensburg agreed that the trier of fact must typically make findings about the standard of care prior to addressing causation, this case required the consideration circumstantial evidence and make findings regarding “what happened” before undertaking the standard of care analysis. In this respect, the facts of this case were analogous to past decisions of the Court endorsing this approach.[20]

The split decision of the Ontario Court of Appeal accentuates the uncertainty of the law, and how application of the standard of care analysis to certain facts may pose challenges. Both the majority and dissenting reasons discuss the standard of care and causation relationship in abstract terms, leaving it unclear when it is appropriate to consider circumstantial evidence. The Supreme Court of Canada has granted leave to appeal, which will hopefully provide much needed clarity.

Metropolitan Toronto Condominium Corporation No. 1100 v. A.& G. Shanks Plumbing & Heating Limited (2020 ONCA 67)

Although the trier of fact ultimately determines the appropriate standard of care, the complexity and expertise of professional negligence claims often necessitate expert witnesses and opinions. The trier of fact does not require expert opinion on the standard of care in two general instances:

  1. in nontechnical matters within the knowledge and experience of the ordinary person; and
  2. where the impugned actions are so egregious that it is obvious that the defendant’s conduct has fallen short of the standard of care without even knowing precisely the parameters of the standard of care.[21]

In Metropolitan Toronto Condominium Corporation No. 1100 v. A. & G. Shanks Plumbing & Heating Limited,[22] the plaintiff was the owner of a historic mansion in Toronto that was destroyed by a fire that occurred during renovations. The fire was detected shortly after a plumber, employed by the defendant, repaired a leaking pipe with a blowtorch and solder. The fire originated in the ceiling near the location of the plumber’s work. The matter proceeded to trial, where the trial judge dismissed the claim after finding no evidence that the plumber’s conduct fell below the standard of care.

The plaintiff did not call expert evidence on the issue of standard of care. It relied exclusively on reference to National Fire Code of Canada 2005 and the Fire Code, O. Reg. 213/07, as well as oral submissions that the plumber’s use of a blowtorch was so egregious that it obviously fell below the standard of care. However, the plaintiff called two causation experts who testified that the fire was caused by the flame of the plumber’s torch coming into contact with combustible materials.

The defendant did not adduce expert evidence on either standard of care or causation, and relied solely on the testimony of the plumber. He testified that he inspected the work area and did not find flammable and combustible materials, did not wet down the area due the recent flooding, pointed the blowtorch in a downward direction and away from the wood structures above him, did not place fire-resistant blankets due to the leak being in the ceiling, and remained onsite for a 30-minute “fire watch.”

The trial judge found the plumber to be a credible witness, and held the plaintiff failed to establish evidence of breach of standard of care and causation. He concluded there was no expert evidence that the National Fire Code of the Ontario Fire Code formed part of the standard of care applicable to plumbers at the time. Further, the soldering work performed was a technical matter requiring expert evidence of the standard of care, and there was nothing obviously egregious about the plumber’s conduct. Accordingly, there was no evidence that the fire was caused by any act or omission of the plumber.

On appeal, the plaintiff argued that the trial judge erred by failing to draw an inference of a breach of standard of care based on the circumstantial evidence, namely that the fire occurred under the plumber’s watch and without alternative explanation as to how it occurred.

Justice Strathy dismissed the appeal on behalf of a unanimous court with brief reasons. Although acknowledging that inferences about standard of care may be drawn from circumstantial evidence,[23] the Court states that it was open to the trial judge to refuse making such inferences in this case. The trial judge was entitled to conclude that the plaintiff failed to prove its case in the absence of supporting expert evidence. Fatally to the plaintiff’s claim, the trial judge was entitled to find that the plumber’s use of the blowtorch was not obviously egregious given the technical nature of soldering. The Court did not interfere with the trial judge’s findings of causation, notwithstanding the fact that the defendants provided no possible alternative explanation for how the fire could have occurred. In short, causation and circumstantial evidence were not indicative of breach.

Although brief, A&G Shanks Plumbing suggests that circumstantial evidence does not replace the burden on the plaintiff to make his or her case. Basing the theory of liability too heavily on the circumstances of the case bring associated risks.


These recent cases pose much food for thought for plaintiffs, defendants, and insurers involved in professional liability litigation. Although it may seem that a defendant fell below the standard of care based on the unique nature of the loss, a plaintiff must still prove that a particular act or omission of the defendant is evidence of a failure to take reasonable care in the circumstances. Armstrong and A&G Shanks Plumbing suggest that the Court will only consider circumstantial evidence in exceptional cases and the plaintiffs are still held to their burden of proof.  Determining when such a case exists remains challenging.  However, the direction of this area of law remains uncertain and may change depending on the Supreme Court of Canada’s future decision in the Armstrong case.

[1] Fullowka v. Pinkerton’s of Canada Ltd, 2010 SCC 5 at para 80.

[2] St-Jean v. Mercier, 2002 SCC 15 at para 53.

[3] Bafaro v. Dowd, 2010 ONCA 188 at paras 35-36, Resurfice Corp v. Hanke, 2007 SCC 7, Randall v. Lakeridge Health Oshawa, 2010 ONCA 537 at paras 33-35.

[4] Armstrong v. Royal Victoria, 2018 ONSC 2439 at para 81.

[5] Ibid at para 82.

[6] 2018 ONSC 2439 at para 109.

[7] Armstrong v. Royal Victoria Hospital, 2019 ONCA 963 at para 44 [Armstrong ONCA]; Carlsen v. Southerland, 2006 BCCA 214 at para 15.

[8] Ibid at paras 48-52.

[9] Armstrong ONCA, supra note 7 at paras 39 and 49.

[10] Ibid at para 40.  

[11] Ibid at para 41.

[12] Ibid at para 46. Justice Paciocco uses the example of a surgeon who leaves a surgical tool inside a patient. “In such cases, it would be harmless in defining the standard of care as outcomes or goals instead of prudent means or behaviours; for example. By finding that it is a breach of the standard of care of a prudent surgeon to leave surgical tools inside a patient or to remove the wrong limb.

[13] Ibid at para 56.

[14] Ibid at para 52.

[15] Ibid at para 62.

[16] Ibid at paras 63-64.

[17] Armstrong ONCA, supra note 7 at para 123.

[18] Ibid at para 134 referring to Hassen v. Anvari, 2003 CanLII 1005 (ON CA) at para 9.

[19] Ibid at para 127.

[20] Ibid see paras 140-144.

[21] Krawchuk v. Scherbak, 2011 ONCA 352 at paras 133-135.

[22] Metropolitan Toronto Condominium Corporation No. 1100 v. A. & G. Shanks Plumbing & Heating Limited, 2020 ONCA 67 [A&G Shanks Plumbing].

[23] A&G Shanks Plumbing, supra note 22 at para 18.