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.
Comparing Categorical and Probabilistic Fingerprint Evidence

Journal: Journal of Forensic Sciences
Published: 2018
Primary Author: Brandon Garrett
Secondary Authors: Gregory Mitchell, Nicholas Scurich
Type: Publication
Related Resources
How do Labs Ensure Quality? A Nationwide Review of SOPs for Latent Print Examination
This presentation is from the 108th International Association for Identification (IAI) Annual Educational Conference, Reno, Nevada, August 11-17, 2024. Posted with permission of CSAFE.
Statistics and its Applications in Forensic Science and the Criminal Justice System
This presentation is from the 2024 Joint Statistical Meetings (JSM), Portland, Oregon, August 3-8, 2024.
Silencing the Defense Expert
In the wake of the 2009 NRC and 2016 PCAST Reports, the Firearms and Toolmark (FATM) discipline has come under increasing scrutiny. Validation studies like AMES I, Keisler, AMES II,…
Developing a Repeatable and Reproducible Protocol for Establishing Combined Minutiae Frequencies
Fingerprint minutia types influence LPEs’ analyses and evaluations during casework, with features perceived as rarer generally given more weight. Last year, we reported on examiner perceptions of minutia type frequency.…