> > > > ---------- Forwarded message ---------- > From: robert bristow-johnson <[email protected]> > To: [email protected] > Cc: > Date: Sun, 19 Feb 2012 21:13:51 -0500 > Subject: Re: [EM] élection de trois élection de trois > On 2/19/12 8:53 PM, David L Wetzell wrote: > >> It seems quite a few election rules get quirky in one way or the other >> with a 3-way competitive election. >> >> That might be a point worth considering in the abstract in a paper or >> something.... why are 3-way single-winner elections quirky? >> >> > isn't it obvious? > > > http://en.wikipedia.org/wiki/**Duverger%27s_law<http://en.wikipedia.org/wiki/Duverger%27s_law>
Duverger's law was based on the assumption of FPTP. I'm being more general, suggesting that any single-winner rule(apart from hybrids like a 2-stage rule) will tend to get quirky when there's a competitive 3 way election, which will tend to make it hard to sustain there being 3-competitive parties. . > > > to wit: Duverger suggests two reasons why single-member district plurality > voting systems favor a two party system. One is the result of the "fusion" > (or an alliance very like fusion) of the weak parties, and the other is the > "elimination" of weak parties by the voters, by which he means that the > voters gradually desert the weak parties on the grounds that they have no > chance of winning. > I'm dealing with a fuzzy monster on this more general quirkiness of 3-way competitive elections. That's just one case. > > On Sun, Feb 19, 2012 at 5:31 PM, Jameson Quinn > <[email protected]<mailto: >> jameson.quinn@gmail.**com <[email protected]>>> wrote: >> >> ..., cuz the simple fact of the matter is that IRV works best >> with only 3 candidates. >> >> >> > geez, i wish people used only plain text email. or that the list server > converted every post to plain text, perhaps wrapping lines at 70 columns. > > 2.5, actually. >> >> > yeah, i don't get the reasoning behind David's claim. IRV works just as > well with 4 or more candidates as with 3. if there are 3 nearly equal > candidates IRV may screw up just as bad as if there are 3 nearly equal > candidates with more minor candidates added. i am not assuming "IRV3". > dlw: Cuz, there's more opportunities for the order of elimination to make a difference when you eliminate more candidates? > I don't think there's a big diff between IRV w. 3 candidates and IRV with > 4 candidates, but my debates with Dale Sheldon Hess have confirmed that > according to the measures they found with simulations that IRV was closest > to their favorites with only 3 candidates. > -- > > r b-j [email protected] > > "Imagination is more important than knowledge." > > > > > > > ---------- Forwarded message ---------- > From: Richard Fobes <[email protected]> > BTW, Richard, you're a pretty good dancer!!! I saw the U-tube video from your website... > > As for the U.S., the biggest (but not the only) election unfairness occurs > in primary elections as a result of vote splitting. "Special interests" -- > the people who give the largest amounts of money to election campaigns -- > have learned to give money to candidates in the primary elections of _both_ > the Republican party and the Democratic party (as needed), and give > additional support to "spoiler" candidates when needed. The result is that > the money-backed candidate in each party's primary election wins, and then > it doesn't much matter whether the Republican or the Democrat wins the > "general election". > dlw: Our system is too entrepreneurial with pretty weak intra-party diffs to maintain party brands against this sort of opportunism. IRV(and other rules) gets rid of some primaries. > > Simply getting one political party or the other to use a fairer voting > method (any of the ones supported by the Declaration of Election-Method > Reform Advocates) in the primary elections would greatly improve the > ability of voters to elect problem-solving leaders -- instead of > special-interest puppets. (After one party adopts such fairer primary > elections, the other party would soon have to do the same or else risk > losing lots of support.) > dlw: primaries are good places to push for electoral reform. > > That's all I have time to write now. > > Richard Fobes > > > > ---------- Forwarded message ---------- > From: Kevin Venzke <[email protected]> > To: election-methods <[email protected]> > Cc: > Date: Mon, 20 Feb 2012 02:39:40 +0000 (GMT) > Subject: Re: [EM] élection de trois élection de trois > They are quirky because of IIA. The papers on this are from the 1970's. > Quote Wikipedia: > > "The *Gibbard–Satterthwaite theorem*, named after Allan > Gibbard<http://fr.mg40.mail.yahoo.com/wiki/Allan_Gibbard>and Mark > Satterthwaite <http://fr.mg40.mail.yahoo.com/wiki/Mark_Satterthwaite>, is > a > result about the deterministic voting > systems<http://fr.mg40.mail.yahoo.com/wiki/Voting_system>that choose a single > winner using only the preferences > of the voters, where each voter ranks all candidates in order of > preference. The Gibbard–Satterthwaite > theorem states that, for three or more candidates, one of the following > three things must hold for every > voting rule: > > 1. The rule is dictatorial (i.e., there is a single individual who can > choose the winner), or > 2. There is some candidate who can never win, under the rule, or > 3. The rule is susceptible to tactical > voting<http://fr.mg40.mail.yahoo.com/wiki/Tactical_voting>, > in the sense that there are conditions under which a voter > > with full knowledge of how the other voters are to vote and of the rule > being used would have an incentive to vote in a manner that does not > reflect his preferences. " > dlw: Hmm, doesn't this cast a different light on the fact that in Burlington VT the Republican voters were susceptible to tactical voting for the Democratic candidate? > One cannot say that there'd never be a situation where such could arise > with seemingly any election rule, which gets to my point that with IRV or > IRV+ that the pressure to vote strategically incidence is on supporters of > a major party that has been ideologically captured by its extreme and > thereby refuses to re-center itself nearer to the true center. And that's > not the same thing as forcing dissenters from the two major parties to vote > strategically.... > dlw
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