Skip to content

Comparing Categorical and Probabilistic Fingerprint Evidence

Journal: Journal of Forensic Sciences
Published: 2018
Primary Author: Brandon Garrett
Secondary Authors: Gregory Mitchell, Nicholas Scurich

Fingerprint examiners traditionally express conclusions in categorical terms, opining that impressions do or do not originate from the same source. Recently, probabilistic conclusions have been proposed, with examiners estimating the probability of a match between recovered and known prints. This study presented a nationally representative sample of jury‐eligible adults with a hypothetical robbery case in which an examiner opined on the likelihood that a defendant’s fingerprints matched latent fingerprints in categorical or probabilistic terms. We studied model language developed by the U.S. Defense Forensic Science Center to summarize results of statistical analysis of the similarity between prints. Participant ratings of the likelihood the defendant left prints at the crime scene and committed the crime were similar when exposed to categorical and strong probabilistic match evidence. Participants reduced these likelihoods when exposed to the weaker probabilistic evidence, but did not otherwise discriminate among the prints assigned different match probabilities.

Related Resources

The Contribution of Forensic and Expert Evidence to DNA Exoneration Cases: An Interim Report

The Contribution of Forensic and Expert Evidence to DNA Exoneration Cases: An Interim Report

This report is from Simon A. Cole, Vanessa Meterko, Sarah Chu, Glinda Cooper, Jessica Weinstock Paredes, Maurice Possley, and Ken Otterbourg (2022), The Contribution of Forensic and Expert Evidence to…
How Minutiae Frequency is Perceived and Used by Fingerprint Analysts in the Evaluation of Fingerprint Evidence

How Minutiae Frequency is Perceived and Used by Fingerprint Analysts in the Evaluation of Fingerprint Evidence

Analysts consider the appearance, placement, and number of features within a fingerprint pattern (called minutiae) that correspond when deciding whether two fingerprints originated from the same person. Little is known…
CSAFE Project Update & ASCLD FRC Collaboration

CSAFE Project Update & ASCLD FRC Collaboration

This presentation highlighted CSAFE’s collaboration with the ASCLD FRC Collaboration Hub.
Understanding forensic decision-making with Item Response Theory: Using a NFI firearms study

Understanding forensic decision-making with Item Response Theory: Using a NFI firearms study

This presentation is from the Forensic Big Data Colloquium at the Netherlands Forensic Institute, November 2022. Posted with permission of CSAFE.