Can Jury Instructions Have an Impact on Trial Outcomes, California, 2018 (ICPSR 37956)

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Study Purpose View help for Study Purpose

The purpose of the study was to gain an understanding of how cases are decided upon by juries and to examine the impact of group deliberation on outcomes and whether those outcomes vary as a function of defendant and key witness race, and second whether the use of "implicit bias" jury instructions versus standard jury instructions impact deliberations and verdict outcomes.

Study Design View help for Study Design

The study employed 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) was 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, 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; otherwise they were identical.

Also, to facilitate recruiting participants who were eligible to serve on a federal jury within the district, the study was conducted at a simulated "jury room" suite in a centrally located office building within the Central District of California. Sessions were available at multiple times of the day and days of the week, and the conditions were randomized to ensure there were no time or day-of-the-week confounds with the experimental conditions. Participants were recruited through a multi-pronged outreach strategy.

When recruited participants arrived at the study site, they were seated in a controlled room with a large video screen and seven chairs around a table. They were supplied with a study information sheet that explained the study and their rights as participants. The researcher then described the study procedure and obtained verbal consent from the participants that they understood what the study entailed and agreed to participate. Next, the 70-minute trial video was presented to the group, which was described as an actual trial that had taken place in the Central District of California. After viewing the trial video, participants each filled out a paper "straw" vote form privately, indicating their personal verdict preference (i.e., guilty or not guilty) and their confidence in that verdict on a five-point scale. This "straw" vote was confidential and nonbinding, and jurors were told they could amend their verdict preference at any time.

Also, Following deliberations and documentation of the group's verdict, participants individually completed an electronic survey using laptops provided by the researchers. The survey assessed individual perceptions of the case, evidence, witnesses, attorneys, defendant, an judge; comprehension of jury instructions; influence of jury instructions; memory of case facts; attitudes about a variety of issues; and demographic information. Researchers included a series of scales that measured subtle racial bias among the attitude measures. These scales were drawn from Williams and Eberhart's (2008) Race Conceptions Scale, and from the Subtle Racism Scale (Meertens and Pettigrew, 1997).

Sample View help for Sample

A total of 639 eligible participants successfully completed the study and were assigned to a total of 123 jury groups that were scheduled over an 8-month period of data collection. An additional 13 participants arrived at the site for scheduled sessions, but because the requisite number of "jurors" were not present to be able to run the session, these 13 participants were paid, dismissed, and invited to reschedule. Participants were each randomly assigned to a small jury group consisting of four to seven individuals. While federal criminal juries are comprised of twelve individuals, the smaller juries allowed for a sufficient number of jury units to meaningfully analyze, while not sacrificing a group decision-making process.

Data from three groups that completed the procedure, totaling 16 participants, were removed from analyses: two groups were removed due to technical difficulties during data collection rendering the data unreliable, and one group was removed due to the dismissal of a participant for disruptive behavior, resulting in too few participants remaining to comprise a jury unit of at least four people. Finally, data for one participant from a group of 7 mock jurors was removed due to the participant rushing through the individual measures post-deliberation, and providing nonsensical responses. The analyses are thus based on data from 623 participants and 120 jury groups.

A majority of the participants identified as women (62%) compared to men (38%), and they ranged in age from 18 to 88 years old, with a mean age of 42 years. The majority of participants self-identified as White (56%), while 44% identified as non-White. Specifically, 13% identified as Asian, 13% as Latinx, 6% as Black/African-American, and roughly 12% as a different race or ethnicity. About 32% of participants self-identified as Democrat, and 23% as Republican, with the remainder indicating a different political affiliation or none altogether. Regarding political ideology, the group was relatively balanced, in that 23% of participants identified as conservative, 41% as moderate, and 27% as liberal. Approximately 17% of participants had served on a jury prior to study participation.

Time Method View help for Time Method

Universe View help for Universe

Jury-eligible adults in Central District of California.

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Description of Variables View help for Description of Variables

The datasets included 623 individual cases and 156 variables in the "Individual Level Master Dataset", and 120 jury-unit cases and 50 variables in the "Group Level Dataset." STRAWVERDICT in the Individual Level Master Dataset was a major dependent variable of interest. This measure was collected individually on paper for jurors just after watching the trial presentation and just before proceeding with group deliberations. Variables labeled "TEST" followed by a number reflect questions that test juror comprehension of the instructions, and Variables that begin with "BIO" reflect biological perceptions of race. Variables that end in "_COUNT" reflect counts of responses within a group. GUILTYSTRAWVOTES_COUNT reflects the number of jurors in the group who indicated during the individual straw poll conducted prior to deliberations that they wanted to vote guilty. The datasets also included additional demographic variables such as age, gender, ethnicity, and religion of the participants.

Response Rates View help for Response Rates

Not available

Presence of Common Scales View help for Presence of Common Scales

The study used the following scales:

Race Conceptions Scale (Williams and Eberhart 2008)

Subtle Racism Scale (Meertens and Pettigrew 1997)

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Original Release Date View help for Original Release Date

2023-04-13

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Weight View help for Weight

Not applicable

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