Scottish jury research: findings from a mock jury study

Annex B - Assessing mock jury research

The majority of empirical exploration of jury decision-making has been conducted using mock jury studies.^[113] This is, in part, a result of legal restrictions which limit the scope for researchers to interview actual jurors about their experience of real criminal trials.^[114] Mock jury studies simulate the experience of sitting on a jury by asking participants to read, listen to, or watch trial materials and then return a verdict. The trial materials used are generally fictional and significantly abbreviated in comparison with a real criminal trial.

Mock jury studies vary greatly in the extent to which their findings are generalisable - that is, in how far their findings are likely to apply to real juries, deliberating in actual criminal trials.^[115] It is therefore important to understand the research methods used by any mock jury study before assessing how much weight to put on its findings. Four questions in particular need to be considered:^[116]

• How representative was the sample of mock jurors? Academic mock jury studies sometimes use a convenience sample of students (who often participate in exchange for course credit). This inevitably means that the profile of their 'mock jurors' is quite different to that of real jurors in terms of characteristics like age and education. Researchers have debated how much this matters in terms of the wider generalisability of the findings. A meta-analysis has suggested that it makes little difference,^[117] although others have disagreed.^[118]
• How realistic were the trial stimulus materials? To create as realistic an experience as possible, many mock jury studies show participants an audio-visual enactment of a trial (either a video or a live re-enactment). However, other studies have used written trial transcripts or study packs instead. This approach is clearly less realistic in terms of recreating the experience of attending a criminal trial. Even where jurors are shown a video or live re-enactment of a trial, it is important to assess how closely this reflects the reality of a criminal trial (for example, in terms of the accuracy of any legal instructions provided).
• Did mock jurors deliberate? Real juries are required to deliberate as a group before returning a collective verdict. However, some mock jury studies do not include this element - they simply ask individual mock jurors what they think the verdict should be after they have read, listened to, or watched the trial materials. Studies that do not include an element of group deliberation are self-evidently less realistic.^[119] Even in studies where deliberation is included, the time allowed for this is sometimes very short. The size of mock juries can also be much smaller than they would be in both Scotland and in most other English language jurisdictions - groups of six to eight are common.
• How seriously did mock jurors engage with their 'role'? Mock jurors are obviously aware that they are role-playing and that, as such, their decisions will not have 'real' consequences. That said, there is evidence from some studies that mock jurors engage very conscientiously with their role and express stress regarding their verdict choices.^[120] To increase the likelihood of mock jurors taking their task seriously, it is important that studies take as many steps as possible to maximise the solemnity of proceedings, such as using appropriate venues and directing mock jurors about their role in a similar way to real jurors.