A Forensic Science Informational Video Can Help Mock Jurors Evaluate Forensic Expert Testimony

• Published date: 01 November 2023
• DOI: http://doi.org/10.1177/00938548231195112
• Author: Devon E. LaBat,Deborah Goldfarb,Jacqueline R. Evans,Nadja Schreiber Compo,Cassidy J. Koolmees,Gerald Laporte,Kevin Lothridge
• Date: 01 November 2023
• Subject Matter: Articles

CRIMINAL JUSTICE AND BEHAVIOR, 2023, Vol. 50, No. 11, November 2023, 1716 –1736.

DOI: https://doi.org/10.1177/00938548231195112

Article reuse guidelines: sagepub.com/journals-permissions

© 2023 International Association for Correctional and Forensic Psychology

1716

A FORENSIC SCIENCE INFORMATIONAL VIDEO

CAN HELP MOCK JURORS EVALUATE

FORENSIC EXPERT TESTIMONY

DEVON E. LABAT

DEBORAH GOLDFARB

JACQUELINE R. EVANS

NADJA SCHREIBER COMPO

CASSIDY J. KOOLMEES

GERALD LAPORTE

KEVIN LOTHRIDGE

Florida International University

Forensic science is a central component of jurors’ decisions in many criminal cases. Nevertheless, research has shown that

jurors are not sensitive to violations of testimonial guidelines for expert testimony in court and generally struggle to compre-

hend and evaluate forensic science testimony. Consequently, the U.S. Department of Justice (DOJ) developed the Uniform

Language for Testimony and Reports (ULTR) to standardize the language used in such testimony. The current study created

and tested a Forensic Science Informational (FSI) video as an intervention to bolster jurors’ understanding of FSI. After read-

ing a case summary, participants were randomly assigned to read and rate five forensic expert testimony violations without

any training, or to watch the FSI video before reading and rating each violation. Results revealed that participants with video

exposure rated both the expert testimony and the expert themselves lower than those without such exposure, indicating they

recognized the violations.

Keywords: juror decision-making; forensic; psychology; law; criminal justice system

Despite the centrality of forensic science to jurors’ decisions in many criminal cases,

there is reason for concern regarding jurors’ comprehension of such testimony

(Association of Forensic Science Providers, 2009; Koehler, 1996; Martire et al., 2013;

Thompson & Schumann, 1987). There is also reason for concern about the scientific

AUTHORS’ NOTE: This research was funded by the National Institute of Justice (NIJ-2019-15645). We thank

the participants and FIU’s Global Forensic Justice Center. We have no conflicts of interest to disclose. The

study materials and data are available on the Open Science Framework (OSF) at https://osf.io/d5vsb/.

Correspondence concerning this article should be addressed to Devon E. LaBat, Florida International

University, 11200 SW 8th Street, DM 268D, Miami, FL 33199, USA; e-mail: dlabat@fiu.edu.

1195112CJBXXX10.1177/00938548231195112Criminal Justice and BehaviorLaBat et al. / A Forensic Science Informational Video

research-article2023

LaBat et al. / A FORENSIC SCIENCE INFORMATIONAL VIDEO 1717

accuracy of statements made by forensic experts on the stand. In 2009, the National

Academy of Sciences’ (NAS) National Research Council (NRC) released a report that, in

part, called for improving the presentation of forensic science in testimony and reports. The

NAS recommended that court testimony and scientific reports should be standardized

through established guidelines for reporting the results of forensic tests. The report sug-

gested that the terminology used by forensic scientists “can and does have a profound effect

on how the trier of fact in a criminal or civil matter perceives and evaluates scientific evi-

dence” (NRC, 2009, p. 21). As such, an intervention to help jurors recognize when forensic

experts provide inappropriate testimony is critical.

In the following pages, we review the empirical research that has focused on jurors’

assessments of evidence and forensic expert testimony, including a discussion of the utility

of different interventions designed to improve jurors’ assessments of testimony and evi-

dence. We also discuss the implementation of informational videos as a potential interven-

tion to improve jurors’ assessments of forensic expert testimony. Finally, we introduce the

novel informational video we created for the present study and test its utility as to this goal.

THE IMPACT OF FORENSIC EXPERTS’ TESTIMONY ON JURORS’ ASSESSMENTS

OF EVIDENCE

Previous research has explored several ways in which a forensic expert’s testimony can

impact jurors’ assessments of evidence. First, jurors may have difficulty comprehending the

statistical analysis and language used to convey forensic science (Martire et al., 2013;

McQuiston-Surrett & Saks, 2009). Psychological research has largely shown that people in

general struggle to understand probabilities, statistics, normative models, and likelihood

ratios, all of which can be used to convey forensic evidence (Association of Forensic

Science Providers, 2009; Koehler, 1996; Martire et al., 2013; Thompson & Schumann,

1987). Research more specifically related to jurors’ comprehension of statistics has found

that jurors tend to improperly evaluate probabilistic evidence (Koehler, 1996; Nance &

Morris, 2005; Schklar & Diamond, 1999). For example, Thompson and Schumann (1987)

found that when participants were provided with conditional probabilities (i.e., there is “a

two percent chance the defendant’s hair would be indistinguishable from that of the perpe-

trator if he were innocent,” p. 173), participants made erroneous judgments about the prob-

ability of the suspect’s guilt (e.g., 98% chance of guilt). Despite these findings, jurors can

be overly confident in their ability to understand the evidence presented by forensic experts

(McQuiston-Surrett & Saks, 2009). This may lead to a mismatch between jurors’ actual

understanding of forensic evidence compared to jurors’ assessments of their

comprehension.

Second, forensic science testimony itself can suffer from data presentation errors, includ-

ing overestimations of the probative value of the evidence and overstatements of the preci-

sion and accuracy of the science by experts (Eastwood & Caldwell, 2015; Garrett & Neufeld,

2009). Garrett and Neufeld (2009) determined that in the 137 wrongful conviction trial

transcripts that they analyzed, 60% of the cases included invalid forensic science testimony.

These trials included testimony that implied that a defendant could be the source of some

evidence when in fact the evidence was nonprobative, testimony that discounted exculpa-

tory evidence, inaccurate statistics, and statistics (numerical and nonnumerical) that lacked

empirical support. Gould and colleagues (2014) similarly found that the most common