Jury Deliberation and the Accuracy of Verdicts
A study of 300 mock juries found that deliberation improved verdict accuracy in cases with ambiguous evidence, but not in cases with clear evidence. In ambiguous cases, juries that deliberated chose the correct verdict 68% of the time, compared to 52% for juries that did not deliberate. In clear cases, deliberating juries were correct 85% of the time, while non-deliberating juries were correct 84%. The study's authors conclude that deliberation helps only when evidence is ambiguous. A critic argues that the study's definition of 'correct verdict' was based on the judgments of a panel of judges, who may share biases. The critic also notes that the mock juries were composed of college students, not representative of actual juries.
1. What is the author's main conclusion?
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The authors conclude that jury deliberation improves verdict accuracy only in ambiguous-evidence cases, not in clear-evidence cases. The data support this: a 16-point improvement (68% vs 52%) in ambiguous cases versus a 1-point difference (85% vs 84%) in clear cases. The passage reports this conclusion and then presents a critic's challenges to the study's measure and sample.
2. Which of the critic's points most directly undermines the study's conclusion?
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The more direct challenge is the validity of the 'correct verdict' measure. If the judges' panel shares biases, then the benchmark against which accuracy is measured may be systematically wrong, and the reported 68% vs 52% difference could reflect agreement with judicial bias rather than true accuracy. The college-student sample affects generalizability but does not necessarily invalidate the internal comparison between deliberating and non-deliberating groups, assuming assignment was random. The measurement critique goes to the dependent variable itself.
3. If the study's finding is accurate, what policy implication follows for juries in clear-evidence cases?
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If deliberation does not improve accuracy when evidence is clear, then from an accuracy-only standpoint, deliberation could be shortened or streamlined in such cases without sacrificing correctness. However, the passage does not address other functions of deliberation, such as legitimacy, satisfaction, or error correction. A policy recommendation would need to weigh those values. The finding alone does not justify eliminating deliberation; it only weakens the accuracy-based argument for it in clear cases.