Academic

Kaye on Individuation, Probability, and Forensic Evidence

By Lawrence Solum

David H. Kaye (Arizona State University - Sandra Day O'Connor College of Law - School of Life Science) has posted Probability and Individuality in Forensic Science Evidence on SSRN.  Here is the abstract:

Day in and day out, the testimony of criminalists reflects the paradigm of positive, uniquely specific identification of fingerprints, DNA profiles, bullets, handwriting, and other trace evidence. Commentators from other disciplines have called for a "paradigm shift" that would replace talk of individualization with statements of probabilities or would exclude certain testimony pending better research on the ability of analysts to perform as claimed. With rare exceptions, however, the courts have failed to perceive the gap between optimistic theory and hard proof, and they have accepted weak forms of validation. Now that Congress has called on the National Academy of Sciences to "disseminate best practices and guidelines concerning the . . . analysis of forensic evidence," a new opportunity to reassess the long-entrenched claims of individualization is at hand. This essay seeks to contribute to such a reassessment by examining the arguments of two of the most powerful critics of this aspect of forensic science, Professors Michael Saks and Jay Koehler. The "individualization fallacy" they describe implicates issues in philosophy, logic, mathematics, psychology, and statistics. This essay argues that contrary to one possible reading of their work, there is no rule of logic or ontology that prevents individualization and that testimony as to uniqueness is acceptable in some situations. It suggests a combination of evidentiary rules and practices to avoid the excesses of the current form of testimony.

Full post as published by Legal Theory Blog on September 29, 2008 (boomark / email).