Measuring Attitudes toward the Insanity Defense in Venirepersons: Refining the IDA-R in the Evaluation of Juror Bias 1

Abstract

The negative attitude against the insanity defense held by venirepersons has a direct effect on individuals with mental illness who are in contact with the criminal justice system. Identifying factors in jurors that support negative attitudes is critical in trying to ensure that the insanity defense is given full consideration when pleaded by people with mental illnesses. This article used the Insanity Defense Attitude scale-Revised (IDA-R; Skeem, Louden, & Evans, 2004) to evaluate attitudes and factors supporting bias in 239 venirepersons. Through the use of confirmatory factor analyses a refined factor model was developed for the IDA-R, which was cross-validated on a sample of 567 undergraduates. Greater support for the death penalty and higher perception of insanity defense use were both related to a more negative attitude toward the insanity defense. Implications for jury selection and the fair treatment of individuals with mental illness are discussed.