Information Aggregation with Runoff Voting

A majority of truth-seeking voters wants to choose the alternative that better matches the state of the world, but may disagree on its identity due to private information. When we have an arbitrary number of alternatives and also sophisticated partisan voters exist in the electorate, the election of the correct alternative is a real challenge. We show that multi-round runoff voting achieves asymptotically full-information equivalence. That is, when the society is large, it can lead to the election of the correct alternative under fairly general assumptions regarding the information structure and partisans' preferences