CondorcetMethoden

Condorcetmethoden, also known as Condorcet methods, are a family of voting procedures in social choice theory that determine outcomes from pairwise comparisons of candidates. Named after Nicolas de Condorcet, the central concept is the Condorcet winner: a candidate who would defeat every other candidate in a head-to-head election according to the voters’ preferences. If such a candidate exists, many Condorcet methods elect or rank that candidate accordingly. However, Condorcet winner existence is not guaranteed; cycles in majority preference, known as the Condorcet paradox, can occur (A beats B, B beats C, C beats A).

Variants and examples include: the Copeland method, which assigns scores based on wins in pairwise matchups; the Schulze method, which uses the strongest paths between candidates to determine the winner; Ranked Pairs (Tideman), which orders pairwise margins and locks in wins without creating cycles; and the Kemeny-Young method, which seeks a ranking minimizing the total distance to voters’ preferences and is computationally intensive. The Borda count, while popular, is not a Condorcet method because it does not necessarily elect the Condorcet winner and can violate pairwise outcomes.

Uses and considerations: Condorcet methods aim to reflect broad pairwise support and are often praised for respecting the Condorcet criterion when a winner exists. They can handle complete or ranked ballots, but may be sensitive to strategic voting and can be computationally complex in larger elections. In practice, different Condorcet methods may yield different winners in cycles, making tie-breaking or additional rules necessary.