The law on this subject evolved in an era ¹ in which it was necessary to prove the intent of the wrongdoer. Due to the inherent difficulty in so doing, two important human rights interpretative principles developed.

The first was the need to prove a prima facie case, which then put the respondent to the need to call evidence. The second principle was that of reasonable inference from circumstantial evidence, as reviewed below.

While the need to prove motive has long gone, these two concepts have remained firmly entrenched.

Prima Facie Case

The test for the establishment of a prima facie case is “one which covers the allegations made and which, if they are believed, is complete and sufficient to justify a verdict in the complainant’s favour in the absence of an answer from the respondent-employer”. ²

To present a prima facie case, it must be established that:

1. the complainant is a member of a group protected by the statute; and
2. that he or she was subjected to adverse treatment; and
3. that the subject matter of the complaint as alleged was a factor in the alleged adverse treatment.³

This is so whether the discrimination is direct or indirect. ⁴

The third branch of this test may include "some consideration of whether the adverse treatment was based on stereotypical or arbitrary assumptions".⁵ Not any nexus, no matter how remote, is sufficient.⁶

It is this last factor in the test which generally presents the real difficulty to the applicant’s case. It is true that there must be a causal link established, albeit as a factor in the decision making.

To show a prima facie case, it is not required to show that all members of the protected group be impacted in the same manner. The example given by the Ontario Court of Appeal in its 2023 decison is an employer policy which denied benefits to employees during pregnancy. The Court noted that even though all members of this group, that is, women, become pregnant, nonetheless, the rule treats women in a discriminatory manner. That is to say, because the adverse treatment effects only part of the group and not all members, it remains discriminatory. ⁷

Employer's Response to Prima Facie Case

The establishment of a prima facie case is one which requires credible evidence to prove the case, and hence a respondent faced with such a prima facie case at the end of the claimant’s case must call evidence to avoid an adverse finding. ⁸ “Once there is evidence to support a prima facie case, the respondent faces the tactical choice: explain or risk losing”. ⁹

The burden of proof then shifts to the respondent to provide a reasonable explanation for the behaviour, one which shows that there was some other reasonable credible explanation for its conduct. ¹⁰

The employer in response may either show evidence to rebut the prima facie case and/or put forward a defence to justify the discrimination. ¹¹

Where the employer defends the case on its merits, this step requires the employer respondent to show some other factor was the sole and only reason for the alleged wrongdoing. ¹²

If the respondent provides such an explanation, the complainant then has the ultimate burden of showing that the alleged offensive discriminatory behaviour is more probable from the evidence than the defence offered. It is in this sense that the burden which shifts is one of evidence, and not onus. ^{13 14}

By showing the above facts, a prima facie case is then established. As discussed subsequently, the evidentiary burden then shifts to the employer to call affirmative evidence to prove its defence.

Such, however, is not the case where the respondent relies upon a statutory defence, in which context the burden of proof does shift. ¹⁵

For the duty to accommodate to arise, there must first be shown such a prima facie case.

The Final Test

The ultimate issue is whether the evidence presented by the complainant, by inference or otherwise, of discrimination is more probable on the evidence than the actual explanations offered by the respondent. ¹⁶The “persuasive burden throughout the case is the balance of probabilities". ¹⁷