Majoritarian Democracy Undermines Truth-Finding in Deliberative Committees

Abstract

The median of independent judgments usually outperforms most individual estimates of vaguely known facts. This wisdom-of-crowd phenomenon emerges from largely dispersed individual estimates whose aggregate is typically less biased than the average individual. Since democracy is to aggregate people's diverse preferences and judgments, it is crucial to identify voting rules promoting the wisdom of crowds. While the median voter theorem favors the majority rule, the theory of deliberative democracy highlights the importance of opinion exchange and revision of judgments. We show experimentally, however, that a combination of majority rule and deliberation worsens collective judgments compared to deliberation under unanimity or no decision rule even without conflicting interests among discussants. Thus, the truth-finding competence of committees is significantly weakened by the majority rule.

Keywords: collective judgment, experimental political science, voting, deliberation

JEL Classification: C92, D70