One of Jim's "criteria" was "system easily explained." Surprisingly, he put "somewhat" for both IRV and Condorcet.
IRV is much easier to explain than Condorcet, and I believe that is the primary reason that it is more popular.
An IRV promoter simply explains that the voter ranks the candidates, and the first choices are counted. So far the counting procedure it is identical to our current plurality system. Then the promoter explains that if nobody gets a majority, the candidate with the least votes is eliminated, and any voter who had that candidate at the top of his list has his next choice bumped up to the top. The counting is then repeated, again as if it were a plurality election. The process repeats until some candidate gets a majority.
My point is that the counting procedure is very similar to our current system. The only twist is the elimination of candidates and transfer of votes, which most people can grasp fairly quickly.
The fact that IRV is non-monotonic and non-summable never even occurs to perhaps 99% of those who hear about it, and the activists who know about these deficiencies don't consider them important. IRV is popular because its rules are simple and the basic counting procedure at each round is identical to plurality.
The same cannot be said for Condorcet, particularly when it involves dropping of defeats. Just explaining the pairwise races and matrix is already more complicated than IRV. Then when you start talking about dropping defeats, people start wondering what sort of crackpot scheme it is. By the time you get into the actual *rules* for dropping defeats, the game is over. Get into "margins" vs. "winning votes" and the poor listener wishes he were late for a root canal.
"Traditional" Condorcet with dropping of defeats may be appropriate for organizations of people with a special common interest, but it will never be accceptable for highly contentious public elections. The Bird Watchers of America may be willing to agree to use defeat-dropping Condorcet, but a large public jurisdiction never will. And think about what would happen if they did: the losing side would immediately become biased against the method. It's just too complicated and too arbitrary.
The general public expects the rules of a public voting system to be simple and easily understood. The public acceptability of a method goes down by perhaps nearly an order of magnitude for each additional sentence required to explain it. That's what I think, anyway.
--Russ ---- Election-methods mailing list - see http://electorama.com/em for list info
