Skip to content

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 =.

Related Resources

Judges and forensic science education: A national survey

Judges and forensic science education: A national survey

In criminal cases, forensic science reports and expert testimony play an increasingly important role in adjudication. More states now follow a federal reliability standard, which calls upon judges to assess…
Juror appraisals of forensic evidence: Effects of blind proficiency and cross-examination

Juror appraisals of forensic evidence: Effects of blind proficiency and cross-examination

Forensic testimony plays a crucial role in many criminal cases, with requests to crime laboratories steadily increasing. As part of efforts to improve the reliability of forensic evidence, scientific and…
Mock Jurors’ Evaluation of Firearm Examiner Testimony

Mock Jurors’ Evaluation of Firearm Examiner Testimony

Objectives: Firearms experts traditionally have testified that a weapon leaves “unique” toolmarks, so bullets or cartridge casings can be visually examined and conclusively matched to a particular firearm. Recently, due…
Mock Juror Perceptions of Forensics

Mock Juror Perceptions of Forensics

This CSAFE Center Wide webinar was presented on December 8, 2020 by: Brandon Garrett – L. Neil Williams Professor of Law, Faculty Director at the Wilson Center for Science and…