NCJ Number
110169
Journal
Law and Human Behavior Volume: 12 Issue: 1 Dated: (March 1988) Pages: 1-17
Date Published
1988
Length
17 pages
Annotation
This study examines individuals' ability to use statistical information and their ability to understand and use an expert's Bayesian explanation of that evidence.
Abstract
Specifically, the study assesses the two major assumptions underlying the proposed use and criticism of Bayes' theorem in the trial process. First the study examines individuals' ability to integrate statistical evidence into the other more qualitative evidence of the case. Based on previous research in this area, individuals are expected to underuse this information. Second, individuals' ability to understand and use a Bayesian presentation is studied. No a priori hypotheses are offered for this second issue. A total of 180 continuing education students were presented with a transcript purportedly taken from an actual trial and were asked to make several subjective probability judgments regarding blood-grouping evidence. Study results generally support and extend to the trial process the psychological research available on individuals' use of statistical information. Respondents significantly underused the statistical evidence. Except in the AB blood-group condition and where subjects explicitly stated a prior probability, respondents virtually ignored the statistical evidence and the expert's Bayesian explanation of the statistical evidence. Findings suggest courts should be less concerned with jurors being overwhelmed by the complexity of statistical techniques and more concerned with instructing jurors in the relevance of those techniques. 2 tables, 3 figures, and 46 references. (Author abstract modified)