The influence of sample type, presentation format and strength of evidence on juror simulation research

Abstract

This paper is an analysis both of the presentation formats and sample types most frequently used in court case simulations, and of the strength of the evidence given in a trial, which are relevant factors for the verdicts returned by jurors. The samples selected have been taken from citizens eligible as jurors according to Spanish law. Real cases of manslaughter have been used. The results obtained show that the type of sample, the presentation format and the strength of evidence have an independent effect on the jurors’ decisions. The strongest influence on verdict is attributable, first, to the evidence; secondly, to the type of sample; and, finally, to the presentation format. The effects caused by the studied variables on the jurors’ verdict tendency also seem to recur in some of the relevant questions which make them explain and justify their verdicts, the effect being more noticeable with ambiguous evidence.

Keywords:

• Presentation format
• sample type
• strength of evidence
• juror decision-making
• simulations

*All authors contributed equally to this work

*All authors contributed equally to this work

Acknowledgments

This research was supported by a grant the Scientific and Technical Research Office of Spain (I + D BSO2002-03347).

Notes

*All authors contributed equally to this work

1. In the three analyses, 25% of theoretical frequencies below 5 were detected, just on the limit suggested by Brown (1983) for these analyses. They corresponded to the cells students/video/yes and eligible citizens/video/yes, for A1, and students/video/no and eligible citizens/video/no, for A2 and A3.

2. In the analysis of A4, 37.5% of the expected frequencies – students/video/no, students/transcript/no and eligible citizens/video/no – were below 5, which exceeds the 25% limit suggested for log-linear analyses. A delta of 0.5 (Goodman, 1971) was used, because the cell students/video/no was zero.

3. One of the cells – students/video/no – gave an expected frequency below 5.

4. Two of the cells – students/video/no and eligible citizens/video/no – gave an expected frequency below 5.

5. One of the cells – students/video/yes – gave an expected frequency below 5.

6. One of the cells – students/video/no – gave an expected frequency below 5.