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Adverse Inference:
Negative Presumptions for Failing to Present Evidence
Last Updated: June 11 2026
Question: What is an adverse inference in Ontario civil court when the other side doesn’t produce documents or call a key witness?
Answer: An adverse inference is a discretionary evidentiary rule where the court may presume missing evidence or testimony would have been unfavourable to the party who reasonably should have produced it, based on the circumstances and any explanation for the absence. For help protecting your position and organizing persuasive evidence in Ontario matters, contact paralegal services from Vescio Legal Services at (416) 400-8255 for a clear, cost-effective strategy.
Understanding the Principle of Adverse Inference as an Evidentiary Rule Arising from Failure to Produce Evidence
An adverse inference, which may sometimes also be called a negative inference, may occur a litigant fails to provide evidence or fails to provide testimony that was reasonably expected to come from the litigant. Where the litigant fails to provide the expected evidence or the expected testimony, the court may presume that the litigant avoided the evidence or testimony because such was unfavourable.
The Law
The adverse inference presumption is based upon the expectation that if a party has control over evidence, the party would present the evidence unless the evidence was unfavourable to the party. The principle was well explained within the case of Tiwari v. Chevalier, 2022 ONSC 3071, as well as the case of Lane v. Kock, 2015 ONSC 1972, wherein each it was respectively said:
[28] Adverse inferences may be drawn from a party’s failure to produce relevant documents they were required to produce or should have produced. (Sarzynick v. Skwarchuk, 2021 BCSC 443, at para. 190.)
[3] The effect of the failure of a party to testify or to call a material witness or other evidence, is summarized as follows in Sydney N. Lederman, Alan W. Bryant & Michelle K. Fuerst, The Law of Evidence in Canada, 4th ed. (Markham: LexisNexis Canada, 2014) at p. 386:
In civil cases, an unfavourable inference can be drawn when, in the absence of an explanation, a party litigant does not testify, or fails to provide affidavit evidence on an application, or fails to call a witness who would have knowledge of the facts and would be assumed to be willing to assist that party. In the same vein, an adverse inference may be drawn against a party who does not call a material witness over whom he or she has exclusive control and does not explain it away. Such failure amounts to an implied admission that the evidence of the absent witness would be contrary to the party's case, or at least would not support it.
The choice to apply an adverse inference is discretion as was explained within the Court of Appeal case of Parris v. Laidley, 2012 ONCA 755, wherein it was said:
[2] 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.
Summary Comment
The principle of adverse inference is the legal version of saying, if you got it, then flaunt it; and, if a party fails to do so, the court may presume that a party who fails to use evidence does so because the evidence would be unfavourable.
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