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Condorcet Jury Theorem

Game Theory

The Condorcet Jury Theorem states that if each member of a group independently votes correctly on a binary question with a probability greater than one half, then the probability that a majority vote reaches the correct decision increases toward one as the size of the group grows. Named for the Marquis de Condorcet, it is a foundational result of social choice theory offering a mathematical justification for collective decision-making by majority vote.

Facts
Statement
If each voter in a group independently votes correctly on a binary question with probability greater than one half, then adding more voters increases the probability that a majority vote is correct, and in the limit the probability that the majority votes correctly approaches 1 as the number of voters increases. 1
Proof Year
1785 1
Classification
Statement Form
Inequality 1
Connections

Has Statement Form

Inequality, Concepts

In Branch

Source Condorcet's jury theorem - Wikipedia

Proved By

Source Condorcet's jury theorem - Wikipedia
Sources
1. Condorcet's jury theorem - Wikipedia
  • Lead section
    In the limit, the probability that the majority votes correctly approaches 1 as the number of voters increases.
  • Lead section, second paragraph
    The theorem was first expressed by the Marquis de Condorcet in his 1785 work Essay on the Application of Analysis to the Probability of Majority Decisions.
  • In Branch: Probability and Statistics, Lead paragraph
    Condorcet's jury theorem is a statistical theorem about the probability of a given group of individuals arriving at a correct decision.
  • Proved By: Marquis de Condorcet, Lead
    The theorem was first expressed by the Marquis de Condorcet in his 1785 work Essay on the Application of Analysis to the Probability of Majority Decisions
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