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Can Jury Instructions Have an Impact on Trial Outcomes?

NCJ Number
Date Published
March 2021
37 pages

This report presents the findings and methodology of a study that tested two primary research questions: 1) Do the races of a defendant and a key witness impact verdict outcomes in a federal drug conspiracy case? and 2) Does the administration of implicit bias instructions impact that judgment process?


The study used a 2 x 2 x 2 factorial design in which the race of defendant (Black or White), race of informant witness (Black or White), and jury instructions (implicit bias or standard bias instruction) were varied, creating eight experimental conditions. To better approximate an actual jury trial, the case was presented as a 70-minute voice-recorded and visual trial presentation. The voice recording was completed using actors trained to play each of the speaking roles (prosecutor, defense attorney, FBI agent, informant, and judge). The voice recording was then overlaid on a digital capture of a quick-moving slide show of 366 photographs representing the trial. The versions of that slide show varied only on the racial characteristics of the defendant and informant, as well as the instructions given to capture the eight experimental conditions. The trial presentation was loosely based on an actual federal narcotics conspiracy trial transcript. A total of 639 eligible participants completed the study and were assigned to 123 jury groups scheduled during 8 months of data collections. The gender, age, race, and political party of each participant was ascertained. The quantitative findings showed no differences in verdict outcomes between those who heard the implicit bias instructions compared to those who heard the standard instructions, either as a main effect or as a function of race conditions. Neither was there a main effect for defendant race and no main effect for the informant race. 2 tables, 2 figures, and 51 references

Date Published: March 1, 2021