Published In
University of Toronto Law Journal
Document Type
Article
Publication Date
2025
Abstract
Forensic evidence, long considered a cornerstone of criminal justice, has faced increasing scrutiny as recent studies and reports expose significant flaws in its scientific foundation. Techniques such as latent fingerprint analysis, microscopic hair comparison, and ballistics matching, which had been widely accepted for decades, are now being challenged for their lack of empirical validation. Reports by the National Research Council and the President’s Council of Advisors on Science and Technology have highlighted the deficiencies in these forensic methods, calling into question their reliability and the weight they are given in courtrooms. Yet despite the growing acknowledgement of widespread issues affecting the reliability and validity of many types of forensic evidence, there are surprisingly few successful challenges to the admissibility of this type of forensic evidence, and when the evidence is challenged, it is often found to be admissible. And while Daubert and Rule 702 mandate that expert evidence be based on reliable principles and methods, many courts have failed to rigorously apply these standards, often deferring to precedent rather than conducting a thorough analysis of the scientific validity of forensic techniques. The article argues that cognitive biases play a significant role in the judicial system's continued acceptance of unreliable forensic evidence. Biases like information cascades, the status quo bias, and the omissions bias can cause judges to favor precedent and established practices, even in the face of new scientific evidence challenging the validity of these forensic methods. The discussion also considers how heuristics, like the bias blind spot, contribute to judges’ reluctance to reject long-standing but scientifically flawed forensic techniques. Notwithstanding these challenges, judicial education on scientific standards, greater diversity on the bench, and a heightened awareness of cognitive biases could help mitigate these issues and promote more rigorous evaluation of forensic evidence in the courtroom.
Citation Details
S. Gordon, "Old Habits Die Hard: Precedent, Psychology, and the Admissibility of Forensic Evidence" University of Toronto Law Journal [forthcoming in 2025].