Fingerprint analysis – The potential flaws, weaknesses and limitations
01 Jun 2012
Following the public inquiry into the Shirley McKie fingerprint scandal at the end of last year, fingerprint analysis has been placed under renewed pressure for improved methods and more careful conclusions. While the inquiry found that there was no reason to suggest that fingerprint comparison in general is an inherently unreliable form of evidence, it recommended that practitioners give due consideration to the limits of the discipline.
Among the key recommendations “for future action” from the inquiry’s chairman, Sir Anthony Campbell, was that “fingerprint evidence should be recognised as opinion evidence, not fact.” He further advised that examiners “should discontinue reporting conclusions on identification or exclusion with a claim to 100% certainty.’
The inquiry also recommended that examiners receive training which emphasises that their findings are based on personal opinion.
Further studies led by Itiel Dror of University College London investigated the potential weaknesses in fingerprint analysis. One study looked at how automated fingerprint identification systems (AFIS), which are frequently used to search print databases and provide a list of possible matches, could influence judgement. Dror gave 23 examiners a print and AFIS lists of possible matches, but changed the position of the actual match on some of the lists. While examiners should regard all AFIS-generated prints as possible matches, Dror’s study found that experts spent longer looking at prints at the top of the list and were more likely to identify one placed here as a correct match, often dismissing the genuine match if it was lower down the list.
Dror said of his study: “This is not a fatal blow to fingerprints, but it means we need to take countermeasures to minimise the effects of bias.” Building on the recommendations of the Fingerprint Inquiry, Dror adds that examiners should always analyse crime-scene prints and document their findings before seeing a suspect’s print or any other contextual evidence in order to avoid bias.
Our forensic fingerprint expert David Goodwin has 32 years’ experience in the specialism of fingerprints and having previously held the position of head of fingerprint services at Northamptonshire police is uniquely placed to provide current, credible forensic opinion on any form of fingerprint evidence.