HMK v Tsang [2023]

Case summary

This case is about how courts approach credibility analysis in sexual assault cases. In this case, the complainant alleged that she was sexually assaulted by the accused while she was affected by alcohol consumption. At the BC Supreme Court, the trial judge convicted the accused of sexual assault, finding that the survivor’s account that she had rejected the accused’s advances to be credible and finding that the accused’s evidence was not believable.

The accused appealed the decision to the BC Court of Appeal on the basis that the trial judge improperly made common-sense assumptions not grounded in evidence and relied on those assumptions when assessing the complainant and accused’s credibility. The accused argued that the trial judge’s analysis ran counter to the so-called “rule against common-sense assumptions” in criminal law. The Court of Appeal agreed with these arguments, overturned the conviction, and ordered a new trial.

The Crown then appealed the Court of Appeal decision to the Supreme Court of Canada (SCC). The legal issues on appeal involved the standard by which a trial judge’s decision can be reviewed, how that review is supposed to take place, and how reviewing courts should weigh evidence when they are assessing common-sense assumptions connected to credibility. This appeal also pertained to concerns about how appeal court’s review of common-sense assumptions can be impacted by the use of harmful, unfounded myths and stereotypes in cases of sexual assault.

This case has significant and concerning impacts for sexual assault complainants, who are more likely to be women, girls, trans, and non-binary people, including those who experience intersecting axes of marginalization arising from their race, Indigeneity, sexual orientation, gender identity, disability status, and age, as well as for the development of sexual assault law. Without clarification of the so-called “rule against common-sense assumption,” survivors of sexual assault could face an increased risk of intrusive, traumatic experiences in the trial process—which already presents a real barrier to survivors of sexual violence.

West Coast LEAF’s involvement

West Coast LEAF co-intervened in this case with LEAF because of the potential wide-reaching impacts of the BC Court of Appeal’s decision and its likelihood to create inconsistencies in sexual assault law. It is already difficult for sexual assault survivors to both access the legal system and navigate the barriers of the trial process. As intervenors, we asked the court to ensure that the approach courts take to common-sense assumptions respects the equality and dignity of sexual assault survivors by distinguishing between legitimate inferences trial judges can make, and unfounded common-sense assumptions based on harmful stereotypes.

West Coast LEAF and LEAF argued that the SCC should reject the reliance on “the rule against ungrounded common-sense assumptions,” as a standalone basis for reviewing trial judge’s credibility findings. We argued that this rule could create inconsistencies and risks that could undermine the dignity and equality rights of complainants. Alternatively, clear guidelines must be put in place to guide its application in sexual assault cases. Without clarity and safeguards, myths and stereotypes about sexual assault will continue to unjustly affect how courts analyze consent and make credibility findings about survivors.

This intervention was built on years of West Coast LEAF’s work on gender-based violence through court challenges to discriminatory or unconstitutional laws in cases such as:

In addition to intervening in cases that impact survivors, our work to combat gender-based violence includes law reform and education, such as:


On March 8, 2024, the SCC released their decision in HMK v Tsang, along with their decision in R v Kruk, ruling against recognizing the proposed rule against “ungrounded common-sense assumptions” as grounding an error of law. In doing so, a majority of the Court emphasized the unique purpose of the prohibition against myths and stereotypes about complainants in sexual assault cases. This decision affirms the importance of protecting survivors’ equality and dignity rights.

The court clarified that the existing rules prohibiting myths and stereotypes do not advantage survivors but aim to address the serious inequality and unfairness that many survivors continue to face in the trial process. The ruling will have a significant impact for sexual assault survivors going through trials and signals a clear recognition of the ongoing harms survivors of sexual violence face in criminal law processes.

Case documents

Application for leave to intervene – HMK v Tsang

Written argument (factum) – Supreme Court of Canada – HMK v Tsang

Decision – Supreme Court of Canada – HMK v Tsang

Read more

Press release: Supreme Court of Canada affirms the dignity of sexual assault complainants

Press release: West Coast LEAF and LEAF intervene at Supreme Court of Canada on common-sense assumptions in sexual assault law