Estimating juror accuracy, juror ability, and the relationship between them.

Abstract

This article advances a method based on standard test theories and measurement models to determine correct verdicts for jury trials, and to estimate juror accuracy, juror ability, and trial difficulty (and the relationships among them). With five vignette cases and 1,318 juror eligible adults as the subjects, the model consistently identified verdicts that accorded with the judge's instructions on the law as correct. With the correct verdicts, the strength of the relationship between juror accuracy and juror ability was found to be substantial. These findings suggest that the assumption of equivalent accuracy of jurors underlying the Condorcet's jury theorem (Condorcet, Essai sur l'Application de l'Analyse a la Probabilite des Decisions Rendues a la Pluralite des Voix, Paris, 1785) may be untenable for general cases where jurors of diverse dispositions and abilities serve together; and that the role of juror ability in determining the accuracy of legal decisions could be more significant than that of attitudes and values because, unlike attitudes and values, ability could affect juror's legal decisions regardless of the type of the case.

Working memory and cognitive load in the legal system: Influences on police shooting decisions, interrogation and jury decisions.

“…Additionally, using complex language resulted in inappropriate compensation. Appropriate, evidence-based outcomes occurred in low-load/low-complexity conditions (also see Park, 2011 for a review of trial complexity and juror ability). Similarly, in a recent study, Reyna et al (2015) tested whether the inconsistency and variability that occurs in civil case damage awards was influenced by jurors’ need for cognition (NFC), which is the disposition to engage in analytical and deliberative thinking.…”

Jury simulation studies: To exclude or not to exclude participants based on a lack of comprehension of the case?

“…Studies that excluded participants based on general memory checks excluded between 0–17% of the total sample. Two studies were unclear about the final number of participants excluded (Park, 2011; Westera et al, 2015).…”

The effect of double judgments on public confidence in court decisions for the trial by citizen-participation in Korea

“…Although jurors do not fare particularly well when tested on their comprehension of legal rules (Reifman et al, 1992), some jurors do understand and follow legal instructions accurately (Feigenson, 2000;Park, 2010). Furthermore, many efforts have been invested to find ways to make jurors comprehend and apply judicial instructions correctly.…”