The Code does not provide a definition of discrimination. Instead, the understanding of discrimination has evolved from case law. To establish prima facie discrimination (discrimination on its face) under the Code, a claimant must show that:
- they have a characteristic protected from discrimination
- they have experienced an adverse impact within a social area protected by the Code, and
- the protected characteristic was a factor in the adverse impact.
The claimant must show that discrimination occurred on a “balance of probabilities,” that is, it is more reasonable and probable than not that discrimination took place. Once a prima facie case has been established, the burden shifts to the respondent to justify the conduct within the framework of the exemptions available under the Code (e.g. bona fide requirement defence). If it cannot be justified, discrimination will be found to have occurred.
As stated earlier, discrimination does not have to be intentional. Intent is irrelevant for establishing that discrimination occurred.
Discrimination is often hard to detect. Direct evidence pointing to discriminatory motives may not be available. Human rights decision-makers have recognized that cases may be shown through an analysis of all relevant factors, including evidence that is circumstantial. As well, human rights case law has established that a Code ground need only be one factor, of possibly several, in the decision or treatment for there to be a finding of discrimination.
The analysis of whether substantive discrimination has taken place should be flexible and look at the full context of the impact of the distinction on the affected individual or group. The contextual factors and relevant considerations may vary slightly based on the type of discrimination claimed (direct, adverse effect, systemic, profiling, etc.), or the ground alleged. However, the legal test and threshold for discrimination do not change.
It is not necessary for language or comments related to a psychosocial disability to be present in the interactions between the parties to show that discrimination has occurred. However, where such comments have been made, they can be further evidence that the psychosocial disability was a factor in the person’s treatment.
 These requirements for establishing discrimination were drawn from Moore v. British Columbia (Education), 2012 SCC 61; R.B. v. Keewatin-Patricia District School Board, 2013 HRTO 1436 at para. 204. Note that, in a few cases, most of which have challenged government services or have raised concerns that different treatment may not amount to discrimination in a substantive sense, disadvantage is not inferred or assumed from the circumstances but may need to be shown by the claimant to establish adverse treatment or impact: see, for example, Ontario (Disability Support Program) v. Tranchemontagne, 2010, supra, note 39; Ivancicevic v. Ontario (Consumer Services), 2011 HRTO 1714 (CanLII); Klonowski v. Ontario (Community Safety and Correctional Services), 2012 HRTO 1568 (CanLII). However, the Court of Appeal for Ontario and HRTO have noted that in most cases under the Code, disadvantage can be assumed where there is adverse treatment based on a prohibited ground and that in most human rights cases it will not be necessary to go through a process of specifically proving what the disadvantage is: see Hendershott v. Ontario (Community and Social Services), 2011 HRTO 482 at para. 45 (CanLII).
 Gray v. A&W Food Service of Canada Ltd. (1994), CHRR Doc 94-146 (Ont. Bd. Inq.); Dominion Management v. Velenosi,  O.J. No. 1277 at para. 1 (C.A.); Smith v.Mardana Ltd. (No. 1) (2005), 52 C.H.R.R. D/89 at para. 22 (Ont. Div. Ct.); King v. CDI Career Development Institutes Ltd. (2001), 39 C.H.R.R. D/322 (Sask. Bd. Inq.).