CONVICTING THE INNOCENT - THE INFERIORITY OF UNANIMOUS JURY VERDICTS UNDER STRATEGIC VOTING

It is often suggested that requiring juries to reach a unanimous verdi ct reduces the probability of convicting an innocent defendant while i ncreasing the probability of acquitting a guilty defendant. We constru ct a model that demonstrates how strategic voting by jurors undermines this basic intuition. We show that the unanimity rule may lead to a h igh probability of both kinds of error and that the probability of con victing an innocent defendant may actually increase with the size of t he jury. Finally, we demonstrate that a wide variety of voting rules, including simple majority rule, lead to much lower probabilities of bo th kinds of error.