Kathy Dopp > Sent: Saturday, June 21, 2008 5:20 AM > "Later-No-Harm", however, is incompatible with the basic > principles of majority rule, which requires compromise if > decisions are to be made. That's because the peculiar design > of sequential elimination guarantees -- if a majority is not > required -- that a lower preference cannot harm a higher > preference, because the lower preferences are only considered > if a higher one is eliminated.
The meaning of the second sentence isn't completely clear to me, but I am fairly sure there is a perverse interpretation of "majority" in the first sentence. An IRV election is an Exhaustive Ballot election contracted into one voting event, instead of being spread over several rounds in which the one candidate with fewest votes is eliminated at each round. It is no surprise that the numbers of voters participating varies from round to round - usually a progressive (or severe) decline. The votes in an Exhaustive Ballot election might look like this: Round 1 A 4,000 B 3,000 C 2,000 D 1,000 Total voting 10,000 Round 2 A 3,500 B 2,500 C 1,500 Total voting 7,500 Round 3 A 3,000 B 2,000 Total voting 5,000. A is the majority winner in Round 3, that is to say, the majority winner of those voters then voting. And IRV satisfies that criterion - and the Exhaustive Ballot is the valid comparison for IRV (because that is the origin of IRV). The only difference is that to ensure the integrity of the count (accounting for all ballot papers at all stages of the count), the ballot papers (votes) of those who opt out at the later stages (rounds) are recorded as "non-transferable". > But many think that > later-no-harm is undesirable "Many" on this list may think that, but it is my experience of more than 45 years as a practical reformer explaining voting systems to real electors, that 'later no harm' does matter greatly to ordinary electors. If they think the voting system will not comply with 'later no harm', their immediate reaction is to say "I'm not going to mark a second or any further preference because that will hurt my first choice candidate - the one I most want to see elected." And of course, if you once depart from 'later no harm' you open the way to all sorts of strategic voting that just cannot work in a 'later no harm' IRV (or STV) public election with large numbers of voters. > But many think that > later-no-harm is undesirable because it interferes with the > process of equitable compromise that is essential to the > social cooperation that voting is supposed to facilitate. If > I am negotiating with my neighbor, and his preferred option > differs from mine, if I reveal that some compromise option is > acceptable to me, before I'm certain that my favorite won't > be chosen, then I may "harm" the chance of my favorite being > chosen. If the method my neighbor and I used to help us make > the decision *requires* later-no-harm, it will interfere with > the negotiation process, make it more difficult to find > mutually acceptable solutions. This is all irrelevant because in a public election there is no negotiation between voter and voter or between voter and candidate. I know that there are proposal for voting system that would incorporate "negotiation" of various kinds, but none of those was under discussion here. James Gilmour No virus found in this outgoing message. Checked by AVG. Version: 7.5.526 / Virus Database: 270.5.6/1574 - Release Date: 25/07/2008 16:27 ---- Election-Methods mailing list - see http://electorama.com/em for list info