Convicting the Innocent: The Inferiority of Unanimous Jury Verdicts under Strategic Voting

Abstract

t is often suggested that requiring juries to reach a unanimous verdict reduces the probability of convicting an innocent defendant while increasing the probability of acquitting a guilty defendant. We construct a model that demonstrates how strategic voting by jurors undermines this basic intuition. We show that the unanimity rule may lead to a high probability of both kinds of error and that the probability of convicting an innocent defendant may actually increase with the size of the jury. Finally, we demonstrate that a wide variety of voting rules, including simple majority rule, lead to much lower probabilities of both kinds of error.

To elect or to appoint? Bias, information, and responsiveness of bureaucrats and politicians

“…Lim's model is a purely ideological model, which precludes the possibility of common values and dispersed information which seem central to the nature of decision-making in the court. This is a common feature of the empirical literature on voting in committees thus far, as the theory of voting with common value elements and dispersed information was developed fairly recently, following the seminal contributions of Austen-Smith and Banks (1996), and Pesendorfer (1997, 1998). 10 In this paper we follow the approach 6 More broadly, there is overwhelming evidence showing that judges are sensitive to the political environment.…”

“…And because the event of being pivotal (all other n j − 1 members voting to rule in favor of the Plaintiff) here carries favorable information for the Plaintiff, in equilibrium all justices become harsher against the Defendant (so as to tilt the equilibrium inference in favor of the Defendant; see Feddersen and Pesendorfer (1998)). As a result, the move to unanimity significantly increases the probability of a mistaken decision against the Defendant (reaching a maximum of 21% for elected justices).…”

“…We do this for two variants of the model: the expressive voting model (where justices care about getting their decision right), and the strategic voting model (Austen-Smith and Banks (1996), Pesendorfer (1997, 1998)), where justices are concerned about getting the court's decision right, and therefore "learn" from their peers in equilibrium. 3 We also estimate justices' common prior belief ρ that the law favors the Plaintiff given case characteristics X.…”

Nicht jede Form von Stress mindert die Entscheidungsqualität: Ein Laborexperiment zur Groupthink-Theorie

“…In Anlehnung an ein Computerexperiment von Guarnaschelli et al (2000), die ein rationales Entscheidungsmodell von Feddersen und Pesendorfer (1998) (Dickerson und Kemeny 2004;Gunnar et al 2009;Kirschbaum und Hellhammer 1994;Lundberg und Frankenhäuser 1980). Die exogenen Bedingungen von Stress wurden der Zeitdruck-Gruppe durch eine ablaufende Sekundenanzeige mit einem als störend empfundenen Tonsignal implementiert.…”

Recent Economic Perspectives on Political Economy, Part I

“…15 One such real world example is the problem faced by members of a jury who would all agree upon a verdict if all uncertainty over a case were removed. 16 That work has shown that any procedure which aggregates private information, such as a jury system, may suffer from strategic, that is non-informative, voting.…”