The validity of latent fingerprint identification: confessions of a fingerprinting moderate

Abstract

How much do we really know about the validity of latent fingerprinting as an identification technique? How confident can we be that a fingerprint examiner’s typical conclusion that ‘this person, and this person alone to the exclusion of all others, was the source of this latent fingerprint’, gets the answer right? Is fingerprint identification one of the most secure forms of evidence we have, or is its scientific validity remarkably untested? Does it even meet the standards for validity required by Daubert v. Merrell Dow Pharmaceuticals, Inc.1 as a prerequisite for legal admissibility? Imagine that I asked two law students to research the answers to these questions. For the sake of this thought experiment, let us further suppose that I arbitrarily restricted the sources that each student could investigate in order to do their research. Let us say that Student A was limited only to the judicial opinions assessing fingerprinting, most of which are in response to challenges to admissibility. By contrast, suppose Student B was steered away from case law and instructed instead only to investigate academic publications, both law reviews and any other academic journal articles or books they could locate. Let us also suppose that both students were instructed to focus on the period after Daubert was decided in 1993. For most inquiries, we would expect these two students to end up with fairly similar answers to their questions. The focal points of academic investigation might be different from those questions central to the judiciary, but we would typically expect that over time, academic views about the validity of a scientific judgement or technique of proof and judicial understandings of probable reliability would converge. If I were to conduct such an experiment regarding, say, whether Bendectin was a likely teratogen, or whether DNA profiling was a valid method for making identifications, both students would, I am confident, reach the answers ‘no’ and ‘yes’, respectively. In the case of latent fingerprint identification, however, my two hypothetical students would reach starkly different conclusions. Student A would likely believe that fingerprinting comfortably