Exploratory research: Is forensic science a cause of miscarriage of justice in Canada?

This exploratory research examines the implication of science in 92 Canadian wrongful convictions officially recognized by the state. The analysis revealed that science played a role in 30 cases, but 97% of those errors stemmed from the misinterpretation or overstatement of reliable scientific results, predominantly in legal medicine, and not from analytical errors. These errors often involved exceeding the probative value of evidence or a confusion between levels of interpretation. In addition, a collaboration with AVANE (Aide aux Victimes des Affaires Non-Élucidés) a French organization providing support and assistance to unsolved cases, allowed to study three cold cases. Despite the small number of cases, all three of them showed an underestimation of the potential of the trace, the ontological nature of scientific evidence and its potential to generate alternative hypotheses to those resulting from investigative tunnel vision or technical and financial constraints. Hence, this exploratory research raises the hypothesis of systemic vulnerabilities: an overestimation of expertise for wrongful convictions (type I errors) and an underestimation of the potential of the trace for unsolved crimes (type II errors). Both types of errors could support a lack of understanding of the trace, its potential, and its limits. Should this exploratory study be confirmed, it would emphasize the need for a stronger forensic oversight all along the investigative process, improved scientific literacy among judicial actors, and frameworks, such as the one proposed by the Sydney Declaration, to better address the inherent complexity and uncertainty of forensic evidence.