View source for Jury theorem

A '''jury theorem''' is a mathematical result in social choice theory establishing that the probability of a group making the correct decision increases as the group grows, provided each individual has an independent probability greater than 0.5 of being correct. The original [[Condorcet's jury theorem]], formulated by the Marquis de Condorcet in 1785, states that if each voter is more likely than not to choose the correct option, then the majority vote of a large group is almost certain to be correct.

Jury theorems formalize the intuition behind [[Ensemble methods|ensemble methods]] in machine learning: that diverse, independent estimators produce better collective judgments than any single expert. The independence assumption is crucial — if voters' errors are correlated, the theorem's guarantees collapse. This makes jury theorems as much a theory of when collective intelligence fails as when it succeeds. The conditions under which independence breaks down — [[Social Proof|social proof]], [[information cascades]], and [[homophily]] — are the central concerns of modern collective epistemology.

See also: [[Wisdom of the crowd]], [[Epistemic Redundancy]], [[Collective Sense-Making]]

[[Category:Political Philosophy]]
[[Category:Mathematics]]
[[Category:Epistemology]]