Our paper titled “Identifying Fingerprint Expertise” has been published in Psychological Science. We describe an experiment where we compare the fingerprint matching performance of experts and novices. We measured the benefit of expertise in matching fingerprints rather than accuracy per se. The difficulty is that no properly controlled experiments have been conducted on fingerprint examiners’ accuracy in identifying perpetrators, even though fingerprints have been used in criminal courts for more than 100 years. We tested fingerprint examiners at police stations across Australia: in Queensland, New South Wales, Victoria, South Australia, and the Australian Federal Police in Canberra. We put examiners in a situation similar to their usual work, but we maintained tight experimental control by using simulated crime-scene prints and highly similar AFIS distractors in a signal detection paradigm.
We show that qualified, court-practicing fingerprint experts are exceedingly accurate compared with novices, but are not infallible. Our experts tended to err on the side of caution by making errors that would free the guilty rather than convict the innocent. They occasionally made the kind of error that can lead to false convictions.