Folks,
A while back I suggested that DMC/RAV should not allow equal rankings. For the record, I now agree with others here that equal rankings should be allowed. Why? Because then a voter can rank all the candidates equally and get the same effect from his vote in as Approval Voting. In other words, allowing equal rankings makes DMC/RAV a proper generalization of Approval. Hence, advocates of AV cannot argue that anything has been lost if the generalization.
Another issue is whether ranking should be allowed for the unranked candidates. I still don't think it should be, at least not for the initial public proposal, and I'll explain why. And please keep in mind that the "initial public proposal" may take decades to get adopted -- if it ever does.
Think about explaining DMC/RAV to the general public. Even with all the publicity behind IRV, I would be willing to bet that the vast majority of the general public is largely unaware of ranked voting. It is a revolutionary concept, and when you try to explain ranked voting, most people are overwhelmed with the implications. They need a while to "digest" the concept -- whether we are talking about IRV, Condorcet, or DMC.
Now imagine that you are trying to explain ranked voting to a general audience and you need to add, "Oh, by the way, you also need to specify an Approval cutoff," or "Oh, by the way, you need to rank the approved candidates and the unapproved candidates separately". You've just elevated the complexity to a new level -- and you've just lost a good portion of the potential converts. In other words, you've made your proselytizing job much harder than it needs to be -- not that it wasn't hard enough to start with!
What else have you done? You also added a major new requirement for the voting equipment -- a requirement that virtually no manufacturer has thought about yet. The IRV advocates have been demanding ranking capability for years, and DMC advocates could be getting the advantage of that effort as a "freeby." But now you add the requirement for two rank lists or an approval cutoff, and you've just lost that huge benefit. Keep in mind that new voting equipment takes years to get fielded even after the requirements are approved by the authorities. Also, a voting method cannot be used until *every* precinct in the relevant jurisdiction is equipped. Counties that have just shelled out tens of millions of dollars on new electronic voting equipment are very unlikely to scrap or upgrade it after just a few years of use.
I also suspect that ranking of unapproved candidates is likely to be very strategic anyway -- shedding little light on the true preferences of the voters. Voters are less likely to vote sincerely on candidates they dislike than candidates they like. I personally would probably just "bury" the unapproved candidate that I thought had the best chance of winning.
By only allowing the approved candidates to be approved, we can significantly simplify the procedure for both the voter *and* the equipment manufacturer. And we can do so at very little "cost" in terms of voting "expressibility." If you are serious about actually getting a new voting system adopted, I urge you to reconsider allowing ranking of unapproved candidates.
--Russ
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