Skip to content

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

Journal: Forensic Science International
Published: 2020
Primary Author: William E. Crozier
Secondary Authors: Jeff Kukucka, Brandon L. Garrett

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 policy groups increasingly recommend routine and blind proficiency tests of practitioners. What is not known is how doing so affects how lay jurors assess testimony by forensic practitioners in court. In Study 1, we recruited 1398 lay participants, recruited online using Qualtrics to create a sample representative of the U.S. population with respect to age, gender, income, race/ethnicity, and geographic region. Each read a mock criminal trial transcript in which a forensic examiner presented the central evidence. The low-proficiency forensic examiner elicited a lower conviction rate and less favorable impressions than the control, an examiner for which no proficiency information was disclosed. However, the high-proficiency examiner did not correspondingly elicit a higher conviction rate or more favorable impressions than the control. In Study 2, 1420 participants, similarly recruited using Qualtrics, received the same testimony, but for some conditions the examiner was cross-examined by a defense attorney. We find cross-examination significantly reduced guilty votes and examiner ratings for low-proficiency examiners. These results suggest that disclosing results of blind proficiency testing can inform jury decision-making, and further, that defense lawyering can make proficiency information particularly salient at a criminal trial.

Related Resources

Using mixture models to examine group difference among jurors: an illustration involving the perceived strength of forensic science evidence

Using mixture models to examine group difference among jurors: an illustration involving the perceived strength of forensic science evidence

The way in which jurors perceive reports of forensic evidence is of critical importance, especially in cases of forensic identification evidence that require examiners to compare items and assess whether…
Battling to a draw: Defense expert rebuttal can neutralize prosecution fingerprint evidence

Battling to a draw: Defense expert rebuttal can neutralize prosecution fingerprint evidence

The present study examined whether a defense rebuttal expert can effectively educate jurors on the risk that the prosecution’s fingerprint expert made an error. Using a sample of 1716 jury-eligible…
CSAFE 2021 Field Update

CSAFE 2021 Field Update

The 2021 Field Update was held June 14, 2021, and served as the closing to the first year of CSAFE 2.0. CSAFE brought together researchers, forensic science partners and interested…
Algorithms in Forensic Science: Challenges, Considerations, and a Path Forward

Algorithms in Forensic Science: Challenges, Considerations, and a Path Forward

This CSAFE webinar was held on May 25, 2021. Presenter: Henry Swofford Ph.D. Candidate – University of Lausanne Presentation Description: Over the years, scientific and legal scholars have called for…