Existing proofs of Condorcet's Jury Theorem formulate only sufficient conditions for its validity. This paper provides necessary and sufficient conditions for Condorcet's Jury Theorem. The framework of the analysis is the case of heterogeneous decisional competence, but the independence...

A weighted scoring rule, Rule L, on three alternative elections selects the winner by awarding 1 point to each voter's first ranked candidate, L points to the second ranked candidate, and zero to the third ranked candidate. The Condorcet winner is the candidate that would defeat each other...