Evaluating the comprehensibility of jury instructions: a method and an example

Methodological problems in jury simulation research involve issues of sampling, choice of stimulus materials, appropriate unit of analysis, appropriate dependent variable, corroborative data, and problems of role playing. Despite these issues, comprehension of jury instructions may be suitable for examination by jury simulation techniques--if certain of these methodological concerns can be satisfied. In a series of 5 experiments using typical Canadian legal instructions on criminal conspiracy and the coconspirator exception to the hearsay rule, this study attempted to validate a simple and inexpensive technique for testing the incomprehensibility of a given set of jury instructions by requiring participants to apply those legal instructions to a set of facts. The results demonstrate the utility of an application test, and suggest that for assessing the comprehensibility of jury instructions, it may be acceptable to use undergraduate students as participants, to use individual participants without group deliberation, and to employ written stimulus materials.