I am more convinced than ever that the best way to measure defeat strength in Beatpath (aka CSSD) is by giving the covering relation the highest priority, and where neither alternative covers the other, falling back on winning votes. This is a natural way to extend the covering relation (which is a partial order) to a total ordering of the candidates.
So if A covers B, then that beatpath with one link is stronger than any beatpath that B can have to A. If neither A nor B covers the other, then all beatpaths in both directions have links (defeats) that are not coverings (because the covering relation is transitive). The strength of a beatpath that has at least one link that is not part of the covering relation is the wv strength of the weakest such link. If we say that A>>B whenever the strongest (in the above sense) beatpath from A to B is stronger than any beatpath from B to A, then the >> relation is a total order barring exact ties at weakest links. If range style ballots are used to infer the voter rankings, then these ties can be resolved without use of randomness. Among the tied candidates give preference to the one with positive ratings on the greatest number of ballots. If the tie is still not resolved, break it by giving preference to the still tied candidate rated above one on the greatest number of ballots. If still tied, give preference to the still tied candidate rated above two on the greatest number of ballots, etc. If we use the above method of defining defeat strength, we can still use the CSSD algorithm to find the Beatpath winner. The method retains its clone free property, and its compliance with the Monotonicity Criterion. Beyond that it always elects an uncovered alternative. ---- Election-Methods mailing list - see http://electorama.com/em for list info
