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Error Rates, Likelihood Ratios, and Jury Evaluation of Forensic Evidence

Journal: Journal of Forensic Sciences
Published: 2020
Primary Author: Brandon Garrett
Secondary Authors: William E. Crozier, Rebecca Grady

Forensic examiners regularly testify in criminal cases, informing the jurors whether crime scene evidence likely came from a source. In this study, we examine the impact of providing jurors with testimony further qualified by error rates and likelihood ratios, for expert testimony concerning two forensic disciplines: commonly used fingerprint comparison evidence and a novel technique involving voice comparison. Our method involved surveying mock jurors in Amazon Mechanical Turk (N = 897 laypeople) using written testimony and judicial instructions. Participants were more skeptical of voice analysis and generated fewer “guilty” decisions than for fingerprint analysis (B = 2.00, OR = 7.06, p =.

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