Venirepersons's attitudes toward the insanity defense: developing, refining, and validating a scale

Given the prevalence and predictive strength of negative attitudes toward the insanity defense, we conducted three studies with 426 venirepersons to develop an understanding and a measure of public attitudes toward the insanity defense. In these studies, we developed, iteratively refined, and cross-validated the insanity defense attitude-revised (IDA-R) scale. The results suggest that IDAs are underpinned by one's degree of (a) orientation toward strict liability, and (b) concern about perceived injustice and danger associated with the defense. The IDA-R assesses these two-dimensions with good internal consistency, convergent and divergent validity, and predictive utility. The IDA-R's predictive utility generalizes across jurisdictions and manipulation of case facts. Theoretical and practical implications for research and for identifying impartial jurors at voir dire are discussed.