Title: Assessing the Legal Relevance of Bullet Lead Evidence: Did the NRC Misfire?

Abstract:

According to the recent National Research Council Report, compositional analysis of bullet lead (CABL) has the potential to be a reasonably accurate way to determine whether two bullets could have come from the same compositionally indistinguishable volume of lead" and "may thus in appropriate cases provide...evidence that ties a suspect to a crime or in some cases evidence that tends to exonerate a suspect." (emphasis added). However, the NRC report did not specify (at least not clearly) the cricumstances under which it would be reasonable to infer that compositionally indistinguishable bullets came from the same source, such as the same box of ammunition. I will argue that the NRC report presents an inadequate and misleading analysis of the legal relevance of CABL evidence by failing to draw an adequate distinction between two evidentiary elements that David Schum and his colleagues have called reliability and diagnosticity, that the report's conclusions appear to rest on the fallacious assumption that one can ascribe meaning to a CABL match based solely on its reliability in the absence of information about its diagnosticity, and consequently that the report's analysis of the admissibility of CABL evidence under the Daubert standard missed the mark.