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Testing the Effects of Selected Jury Trial Innovations on Juror Comprehension of Contested mtDNA Evidence: Final Technical Report

NCJ Number
Date Published
December 2004
198 pages
This study examined whether the use of several jury reform techniques improved juror understanding of expert testimony about mitochondrial DNA (mtDNA).
Innovative trial procedures have been advocated by judges, scholars, and jury reform commissions over the past decade in order to assist jurors in their understanding of complex testimony presented during trials. Reform suggestions range from simple juror note taking to more controversial suggestions such as allowing jurors to question witnesses or permit jurors to discuss the case with one another during the course of the trial. While some reform suggestions seem promising, there is scant research on their impact in the courtroom. The current study explored the use of several jury reform techniques through the use of a controlled mock trial approach. A total of 60 mock juries were run in which jury pool members watched a videotaped armed robbery trial featuring conflicting expert testimony about mtDNA. Some juries simply watched the videotape before deliberating on a verdict, while other juries were allowed to take notes, ask questions relating to the expert testimony, use a checklist, or refer to jury notebooks containing information about mtDNA in the case under question. Results indicated that jurors appreciated the use of innovations and reported that all four innovations aided in their understanding and recall of mtDNA testimony. Statistical analyses of juror comprehension provided mixed results: in some analyses the use of notebooks and a checklist improved juror comprehension whereas in other analyses, no effects on juror comprehension were observed. Suggestions are offered for the presentation of complex evidence in jury trials, including the recommendations to distribute a checklist or inference chart listing the issues presented by complex evidence and to distribute a collection of the expert’s slides, overheads, charts, and other supplementary materials. Footnotes, tables, figures, appendixes

Date Published: December 1, 2004