Re: [EM] eliminate the plurality loser until there is a Condorcet winner
robert bristow-johnson wrote: On May 11, 2011, at 3:51 PM, fsimm...@pcc.edu wrote: James Green-Armytage asked Quick question for everyone: Do you happen to know when the method described in the subject line (eliminate the plurality loser until there is a Condorcet winner) was first proposed? by Plurality Loser, do you mean the candidate who was ranked 1st the fewest times or the candidate ranked last the most times (all who are unranked are tied for last place)? The Plurality loser is the one who ranks last (loser) in the ordering given by Plurality. Hence, among those that you state, it is the former. Essentially, it is IRV, but at every step, you check if there's a CW among the candidates remaining; if there is, that person is elected and you're done. i made mention of either in a paper i wrote in 2009 (The Failure of Instant Runoff Voting to accomplish the very purposes for which it was adopted: An object lesson in Burlington Vermont) right after i figgered out that the Condorcet winner was not the same as the IRV winner (and happened to be the candidate i supported). i would think that this would have preceded by anyone thinking about Condorcet cycle for a minute. Another way of getting a Condorcet compliant runoff method is to do IRV with Borda (Nanson's method), or better, eliminate-below-mean-scores IRV with Borda (Baldwin's method). These methods have actually been used in the real political world, which is not something many Condorcet methods can say, and apparently they also elect from the Smith set. Being runoff methods, however, they are not monotone, and I remember reading that they're quite manipulable. well, when a few more towns toss out IRV, i hope that FairVote gets the message and starts promoting other tabulation methods than STV with the ranked ballot. what makes me so mad is that Burlington people that are IRV supporters (because they are election reform people and do not believe in the two-party religion), these people had no idea that there was another way to look at those very same ballots. Fairvote essentially sold ranked-choice voting with IRV as if they were the same thing. as if there *is* no ranked-choice voting without IRV. FV didn't swerve in their game of chicken, so to speak. They decided to link ranked ballots directly to IRV, presumably so that when people get the (commonsense) idea that perhaps ranking would help break the nation out of the two-party stranglehold, they'll immediately think of IRV. That strategy does have its benefits from FV's point of view, since it makes it more likely that people will pass IRV, but it also is very damaging against the ranked ballot concept in general if/when people then find IRV not good enough. Whether or not they're pursuing IRV for its own sake (and think it's a good singlewinner method) or they're doing it to have IRV be a stepping stone to STV, I don't know. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] eliminate the plurality loser until there is a Condorcet winner
robert bristow-johnson wrote ... i *know* i loosened a few IRV supporters here in Burlington. but, unfortunately, the Keep Voting Simple side that brought us back to Plurality and Delayed Runoff believe that God herself has ordained the vote-for-only-one ballot. we won't be revisiting anything with a ranked ballot again in my lifetime. If they are dead set against anything except vote-for-only-one ballots, then the best they can do is Asset Voting. Kristofer Munsterhjelm wrote ... Whether or not they're pursuing IRV for its own sake (and think it's a good singlewinner method) or they're doing it to have IRV be a steppingstone to STV, I don't know. Asset Voting is just as simple in its single and multi- winner forms, so IRV has no advantage here over Asset Voting. - Original Message - From: election-methods-requ...@lists.electorama.com Date: Thursday, May 12, 2011 12:01 pm Subject: Election-Methods Digest, Vol 83, Issue 14 To: election-methods@lists.electorama.com Send Election-Methods mailing list submissions to election-methods@lists.electorama.com To subscribe or unsubscribe via the World Wide Web, visit http://lists.electorama.com/listinfo.cgi/election-methods- electorama.com or, via email, send a message with subject or body 'help' to election-methods-requ...@lists.electorama.com You can reach the person managing the list at election-methods-ow...@lists.electorama.com When replying, please edit your Subject line so it is more specific than Re: Contents of Election-Methods digest... Today's Topics: 1. Re: eliminate the plurality loser until there is a Condorcet winner (fsimm...@pcc.edu) 2. Re: electing a variable number of seats (fsimm...@pcc.edu) 3. Re: eliminate the plurality loser until there is a Condorcet winner (robert bristow-johnson) 4. Re: eliminate the plurality loser until there is a Condorcet winner (Kristofer Munsterhjelm) - - Message: 1 Date: Wed, 11 May 2011 19:51:24 + (GMT) From: fsimm...@pcc.edu To: election-methods@lists.electorama.com Subject: Re: [EM] eliminate the plurality loser until there is a Condorcet winner Message-ID: Content-Type: text/plain; charset=us-ascii James Green-Armytage asked Quick question for everyone: Do you happen to know when the method described in the subject line (eliminate the plurality loser until there is a Condorcet winner) was first proposed? Forest's attempt at an answer: I don't know about first proposed, but I know that we considered it in passing when we came up with the DMC proposal, one of whose many formulations is to eliminate the approval loser (or candidate ranked on the fewest number of ballots) until there is a Condorcet Winner. We settled on Approval instead of Plurality as the basis for elimination because it seemed a lot better at the time. It turns out that DMC is monotonic, for example, while the Plurality based method is not. Long before that (about ten years ago) I suggested a lot of different tweaks on IRV that would make it Condorcet compliant in an attempt to show IRV supporters how easy it would be to keep IRV from discarding the true majority winner. Mike Ossipoff advised me to forget it, because (having been rebuffed himself after proposing all of these ideas and more) he had found out by sad experience that the hard core IRV supporters were too closed minded to even consideranything other than pure Hare/STV/AV/IRV. Since that time I have found a few staunch IRV supporters that are willing to think about other possibilities, but on the whole Mike seems to have been right. -- Message: 2 Date: Thu, 12 May 2011 00:35:07 + (GMT) From: fsimm...@pcc.edu To: election-methods@lists.electorama.com Subject: Re: [EM] electing a variable number of seats Message-ID: Content-Type: text/plain; charset=us-ascii Raph Frank wrote ... On Fri, Feb 18, 2011 at 7:54 AM, Juho Laatu yahoo.co.uk wrote: If you want to keep this property, the approach proposed by Michael Rouse could determine the number of board members. If most votes go to few candidates, then there would be 5 members (with different weight). If the votes are more distributed, then all candidates (up to 9 candidates) that get support over some agreed limit would be elected. Alternatively one could use the number of unrepresented votes as the criterion on how many members to elect. This approach would improve proportionality and keep the size of the board small at the same time. You could still use PR-STV to give a proportional result. There is a formula which defines the effective number of parties. It is also used in economics to define how many firms there are in a market. The formula is 1/sum((vote share squared)) So,
Re: [EM] eliminate the plurality loser until there is a Condorcet winner
James Green-Armytage asked Quick question for everyone: Do you happen to know when the method described in the subject line (eliminate the plurality loser until there is a Condorcet winner) was first proposed? This idea is implemented as part of the CIVS voting service, where it is called Condorcet-IRV. When I looked into the origins of the idea a while back, I discovered that it had been proposed originally by Thomas Hill of England's Electoral Reform Society. Hope that helps. Best, -- Andrew attachment: andru.vcf Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] electing a variable number of seats
If, in addition to allowing the number of seats to vary, you are willing to allow different weights for different seats, then there is another solution: find the best proportional lottery L (e.g. by use of the Ultimate Lottery), and then, instead of using the lottery L to choose one of the candidates, use it to give weights to the candidates, and then seat only the ones with positive weights.. For example, if the range ballots were 20 A(100) X(90) 20 B(100) X(90) 30 C(100) Y(80) 30 D(100) Y(80), then L would give 40% to X and 60% to Y, so X and Y would be the only candidates seated, and their respective weights would be 40 and 60 percent. Most of the other methods proposed would seat four candidates A, B, C, and D, and give them equal weight. Which do you think is best in this case? Andy, how would you compare these two outcomes with RRV? Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] eliminate the plurality loser until there is a Condorcet winner
On May 11, 2011, at 9:35 PM, robert bristow-johnson wrote: On May 11, 2011, at 3:51 PM, fsimm...@pcc.edu wrote: James Green-Armytage asked Quick question for everyone: Do you happen to know when the method described in the subject line (eliminate the plurality loser until there is a Condorcet winner) was first proposed? I get dizzy trying to sort this out and vote for forgetting most of it. Those of us who agree that a Condorcet winner is a good thing should question wandering away from the X*X matrix that is the heart of this, and is enough to determine whether we have a CW, or have a cycle to decipher. Each cycle member looks up only to other members for preventing that member from being CW - so that matrix is as far as we need to look to decide which is most deserving.. In this thread I see much labor wasted in going back to ballot data rather than reading what we need from the matrix. i was impressed with the bottom-two runoff (BTR) in that it's such a small change to the existing IRV method used in a few places (and used to be in my place). but i've been thinking that, while BTR or some other Condorcet compliant IRV is better than a Condorcet non-compliant IRV, it's still IRV and the actual method of tabulation does not allow for precinct summability. if you demand precinct summability (for reasons of transparency in elections), then it really has to be a simple Condorcet method where you count pairwise tallies locally, post publicly and transmit upward the pairwise subtotals. the election should be decided solely by the totals from the pairwise subtotals. if Ranked Pairs or Schulze is used, the difference between totals of a pair of candidates, the defeat strength, is part of the decision, but it is a derived value from the pairwise totals. Seems like what I wrote above. Mike Ossipoff advised me to forget it, because (having been rebuffed himself after proposing all of these ideas and more) he had found out by sad experience that the hard core IRV supporters were too closed minded i *know* i loosened a few IRV supporters here in Burlington. but, unfortunately, the Keep Voting Simple side that brought us back to Plurality and Delayed Runoff believe that God herself has ordained the vote-for-only-one ballot. we won't be revisiting anything with a ranked ballot again in my lifetime. i hope i'm wrong about that. to even consider anything other than pure Hare/STV/AV/IRV. Since that time I have found a few staunch IRV supporters that are willing to think about other possibilities, but on the whole Mike seems to have been right. well, when a few more towns toss out IRV, i hope that FairVote gets the message and starts promoting other tabulation methods than STV with the ranked ballot. what makes me so mad is that Burlington people that are IRV supporters (because they are election reform people and do not believe in the two-party religion), these people had no idea that there was another way to look at those very same ballots. Fairvote essentially sold ranked-choice voting with IRV as if they were the same thing. as if there *is* no ranked-choice voting without IRV. And we need to do better educating. Dave Ketchum -- r b-j r...@audioimagination.com Imagination is more important than knowledge. Election-Methods mailing list - see http://electorama.com/em for list info
