Simon's Megalomaniacal Legal Resources

Evidence - Adverse Inferences (3)

. Gumbley v. Vasiliou

In Gumbley v. Vasiliou (Ont CA, 2025) the Ontario Court of Appeal dismissed a medical malpactice appeal, here brought against "trial judge’s causation finding that her breaches of the standard of care more likely than not caused Ms. Gumbley’s brain damage".

Here the court considers, but does not directly apply, an issue of adverse inference:

[49] He also summarized the governing principles on drawing an adverse inference of causation, perhaps as a self-caution, at paras. 220-21 of Gumbley:

It has been held that in some circumstances, where a defendant’s negligence is the cause of an absence of evidence, an adverse inference of causation may be drawn against the defendant. As this court found in Fleury (Estate) v. Kassim, 2022 ONSC 2464, 82 C.C.L.T. (4th) 211, at para. 112:

Whether an inference of causation is warranted, and how it is to be weighed against the evidence, are matters for the trier of fact. However, a court must be cautious in this approach in order to avoid creating a consequential reversal of the burden of proof. Benhaim v. St. German [sic], 2016 SCC 48 at para 42 and 66-67.

To similar effect, in Hanson-Tasker v. Ewart, 2023 BCCA 463, the court stated, at para. 80:

... in cases of negligently-created causal uncertainty where a plaintiff adduces some evidence of causation, it is open to a trial judge to draw a causal inference unfavourable to the defendant that serves to discharge the plaintiff’s burden of proof: Benhaim at para. 42. The inference operates as something of a counterweight, offsetting the imbalance and consequent unfairness that may arise, particularly when a defendant seeks shelter in the evidentiary vacuum created by their own negligence and relies on the burden of proof shouldered by the plaintiff to defeat the claim. The underlying policy goal seeks to balance two considerations: (1) ensuring that defendants are held liable for injuries only where there is a substantial connection between the injuries and their fault; and (2) preventing defendants from benefiting from the uncertainty created by their own negligence: Benhaim at para. 66.

[50] However, despite his discussion of the law, the trial judge did not state he was drawing an adverse inference of causation when he found Dr. Vasiliou was the source of Dr. Warner’s information. The point was more subtle. It was open to the trial judge to find Dr. Vasiliou was the source of Dr. Warner’s notation that Ms. Gumbley was intubated because she was hypoxemic. This finding was not an adverse inference of causation; rather, it was an interpretation of a piece of evidence before the court. The trial judge recognized that the inference was not contradicted by evidence of Ms. Gumbley’s oxygen saturation levels in the relevant time frame, because such evidence did not exist as a result of Dr. Vasiliou’s breaches of the standard of care. This evidentiary gap did not prevent the trial judge from reaching the interpretation of Dr. Warner’s note that he did.

[51] Even if this case had come down to an adverse inference, it would have been open to the trial judge to infer causation where a gap in the evidence attributable to the defendant’s negligence prevented the plaintiff from demonstrating the link between the injury and the negligent act. Permitting Dr. Vasiliou to rely on a gap in the evidence that resulted from her breaches of the standard of care would effectively immunize her from liability: see Ghiassi v. Singh, 2018 ONCA 764, at para. 29; Goodwin v. Olupona, 2013 ONCA 259, 305 O.A.C. 245, at paras. 72-74; and Hasan, at paras. 24-25.

[52] The trial judge also cautioned himself, at para. 212 of Gumbley, that the onus of proof of causation stayed on Ms. Gumbley throughout.

[53] The trial judge committed no errors in finding Dr. Vasiliou to be the source of the double hearsay in Dr. Warner’s note.

. Kilback v. Canada

In Kilback v. Canada (Fed CA, 2023) the Federal Court of Appeal considers factual inferences, including adverse inferences:

[61] A failure to file evidence on the points in issue without a reasonable explanation may lead to an adverse inference: Apotex Inc. v. Merck & Co. Inc., 2004 FC 314 at para 28, aff’d 2004 FCA 298; Riva Stahl Gmbh v. Bergen Sea (The), [1999] F.C.J. No. 762 (QL), 243 N.R. 183 (CA) at para. 11. The judge may make inferences of fact based on undisputed facts before the Court, provided they are strongly supported by the facts: Lameman at para. 11, citing Guarantee Co. of North America v. Gordon Capital Corp., 1999 CanLII 664 (SCC), [1999] 3 S.C.R. 423, 178 D.L.R. (4th) 1 at para. 30.

. Watter v. McMaster University

In Watter v. McMaster University (Ont Div Ct, 2025) the Ontario Divisional Court dismissed a JR, this against McMaster University Board of Governors deciding "that adequate cause existed to remove Dr. Watter from his faculty position ... ."

Here the court considered an evidentiary 'adverse inference' issue, addressed in a procedural fairness context:

An adverse inference from the University’s failure to call S.L. as a witness

[71] The applicant submits that his hearing was procedurally unfair as the Hearing Committee failed to properly deal with his argument that an adverse inference should be drawn by the University’s failure to call S.L., who was a key witness. He submits that the Decision was confusing and circular in dismissing this argument.

[72] The Court of Appeal in Parris v. Laidley, 2012 ONCA 755, O.J. No. 5214 at para. 2 explained that:

Drawing an adverse inference from a failure to produce evidence is discretionary. The inference should not be drawn unless it is warranted in all the circumstances. What is required is a case-specific inquiry into the circumstances including, but not only, whether there was a legitimate explanation for failing to call the witness, whether the witness was within the exclusive control of the party against whom the adverse inference is sought to be drawn, or equally available to both parties, and whether the witness has key evidence to provide or is the best person to provide the evidence in issue.

[73] This approach to adverse inferences has continued to be applied by this court: see Warren v. Ontario (Labour Relations Board), 2013 ONSC 847, 305 O.A.C. 52 (Div. Ct.), at paras. 16, 23.

. Ahmad v. Association of Professional Engineers of Ontario

In Ahmad v. Association of Professional Engineers of Ontario (Ont Div Ct, 2025) the Ontario Divisional Court considered the discretionary nature of the principle of adverse inference upon failing to call available evidence:

[28] Failure to adduce evidence that is available to a party may give rise to an inference that the evidence would have been unfavourable to the party: Ma v. Canada (Citizenship and Immigration), 2010 FC 509, 368 FTR 116, para. 1. Drawing - or declining to draw - an inference is a matter of discretion, to be exercised on proper principles: Association of Professional Engineers v. Rew, 2020 ONSC 6018, para. 92.

Drawing adverse inferences from failure to produce evidence is discretionary. The inference should not be drawn unless it is warranted in all the circumstances. What is required is a case-specific inquiry into the circumstances including, but not only, whether there was a legitimate explanation for failing to call the witness, whether the witness was within the exclusive control of the party against whom the adverse inference is sought to be drawn, or equally available to both parties, and whether the witness has key evidence to provide or is the best person to provide the evidence in issue (Parris v. Laidley, 2012 ONCA 755, para. 2.).

. Total Meter Services Inc. v. GVM Integration

In Total Meter Services Inc. v. GVM Integration (Ont CA, 2025) the Ontario Court of Appeal allowed an appeal in part, here from a finding "for breach of fiduciary duty and breach of confidence".

Here the court considered an 'adverse inference' issue where the defendant failed "to produce relevant documents during discovery":

[7] In her assessment of the credibility of Mr. Roberge’s evidence, the trial judge drew an adverse inference against Mr. Roberge on the basis that he failed to comply with his obligation under the Rules of Civil Procedure, R.R.O. 1990, Reg. 194, to produce relevant documents during discovery. ....

....

[11] This evidence provided an ample basis for the trial judge to draw an adverse inference in assessing Mr. Roberge’s credibility for failing to produce the GVM source code in the Visual Basic programming language. As there was an evidentiary basis for the adverse inference (i.e., this is not a “no evidence” situation), the trial judge’s credibility assessment and her decision to draw an adverse inference as part of that assessment are entitled to deference: 1468025 Ontario Limited v. 998614 Ontario Inc., 2016 ONCA 504, at paras. 14-15. I see no palpable and overriding error in her decision to draw an adverse inference.

....

[13] The appellants argue that if the respondent wanted to pursue the issue of the appellants’ failure to comply with discovery obligations under the Rules, it was required to bring a pre-trial motion seeking a remedy under rule 30.06, such as cross-examination on the appellants’ affidavit of documents, a further and better affidavit of documents, or inspection of documents. The appellants argue that, not having brought such a motion, the respondent was taken to have accepted counsel for the appellants’ representation that complete production of the GVM source code had been made.

[14] I disagree. Although a pre-trial motion under rule 30.06 was an option available to the respondent, its choice not to pursue such a motion did not preclude the respondent from seeking an adverse inference at trial. There was no procedural unfairness to the appellants from the respondent arguing at trial that an adverse inference should be drawn against the appellants on the basis of incomplete disclosure of the GMS source code and the fact that it was disclosed in a language other than Visual Basic.