Citation

Scanlon P, Banyai B, Hart E, Cooper SL. South. Calif. Interdiscip. Law J. 2022; 31(1): 91-114.

Copyright

(Copyright © 2022, Gould Law Center, University of Southern California)

DOI

unavailable

PMID

unavailable

Abstract

Firearms examiners compare toolmarks present on suspect ammunition to those present on ammunition test-fired by a suspect weapon to evaluate association between the two. Examiners' conclusions are generally admissible in U.S. courts, yet the scientific underpinnings of the toolmark discipline have been subject to considerable criticism. Cross-examination can be used to bring such criticism to the attention of jurors in order to highlight the flaws inherent in toolmark analysis to those who determine the weight of expert evidence.We investigated the effect of such cross-examination on juror certainty about expert firearms evidence using online vignettes. A community sample of 437 U.S. participants was asked to rate its certainty, on a scale of 0 to 100, of a forensic match between a suspect weapon and suspect ammunition for each of four expert statements of certainty, in two groups; either with or without a cross-examination highlighting limitations of the toolmark discipline's scientific underpinnings. We analyzed differences between both groups and between the statements given to each group.

RESULTS suggest that cross- examination can have a strong influence on juror decision-making, particularly when experts express their conclusions in certain terms.

Language: en