From Electowiki
Revision as of 13:04, 2 May 2005 by Araucaria (talk | contribs) (Added summary of method)

Jump to: navigation, search

River is a cloneproof monotonic Condorcet ambiguity resolution method with similarities to both Ranked Pairs and Cloneproof Schwartz Sequential Dropping, but when cycles exist, can in rare cases find a different winner than either of the other two methods.

Quick summary of method, which is identical to Ranked Pairs except where emphasized:

  • Rank defeats in descending order of winning vote strength.
  • Starting with the strongest defeat, affirm defeats unless a cycle is created or a candidate is defeated twice.

The result is that only sufficient defeat information to determine the winner is included.

Because not all defeats are processed, the social ordering is not linear -- in general it is a tree (or river) diagram, with the victor at the base of the river.

It was first proposed by Jobst Heitzig on the Election-methods mailing list: