Re: [EM] IRV vs Condorcet vs Range/Score
Dave Ketchum wrote: I suggest a two-step resolution: Agree to a truce between Condorcet and Range, while they dispose of IRV as being less capable than Condorcet. Then go back to the war between Condorcet and Range. I think the problem, or at least a part of it, is that if we (the election-methods members) were to advocate a method, to be effective, it would have to be the same method. Otherwise, we would split the vote, as it were, against the status quo. Therefore, both Condorcet and Range groups would prefer their own method to win. If that's true, then one way of uniting without running into that would be to show how IRV is bad, rather than how Condorcet or Range is better. If there's to be unity (or a truce) in that respect, those examples would focus on the properties where both Range and Condorcet, or for that matter, most methods, are better than IRV, such as in being monotonic, reversal symmetric, etc. An expected response is that these properties don't matter because they happen so rarely. To reply to that, I can think of two strategies. The first would be to count failures in simulations close to how voters would be expected to act, perhaps with a reasoning of we don't know what strategy would be like, but the results would be worse than for honesty, so these provide a lower bound. The second would be to point to real uses, like Australia's two-party domination with IRV, or Abd's argument that TTR states who switched to IRV have results much more consistent with Plurality than what used to be the case. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
On Fri, 17 Oct 2008 22:08:32 +0200 Kristofer Munsterhjelm wrote: Dave Ketchum wrote: I suggest a two-step resolution: Agree to a truce between Condorcet and Range, while they dispose of IRV as being less capable than Condorcet. Then go back to the war between Condorcet and Range. I think the problem, or at least a part of it, is that if we (the election-methods members) were to advocate a method, to be effective, it would have to be the same method. Otherwise, we would split the vote, as it were, against the status quo. Therefore, both Condorcet and Range groups would prefer their own method to win. If that's true, then one way of uniting without running into that would be to show how IRV is bad, rather than how Condorcet or Range is better. If there's to be unity (or a truce) in that respect, those examples would focus on the properties where both Range and Condorcet, or for that matter, most methods, are better than IRV, such as in being monotonic, reversal symmetric, etc. First, IRV will slay us all if we do not attend to it - it is getting USED. Range and Condorcet are among the leaders and ask two different conflicting thought processes and expressions of the voters: Condorcet ranks per better vs worse, but asks not for detailed thought: ABC ranks A as best of these three. Range easily rates A-100 and C-0. Same thought as for Condorcet would rate B between them, but deciding exactly where can be a headache. Each of these has its backers, but we cannot devote full time to this battle while we need to defend our turf against IRV. I suggest concentrating on Condorcet disposing of IRV because both use almost identical rank ballots and usually agree as to winner. They look at different aspects: Condorcet looks only at comparative ranking. When they matter, we ask only whether AB or BA is voted by more voters. IRV cares only what candidate ranks first on a ballot, though it looks at next remaining candidate after discarding first ranked as a loser. Sample partial election: 9 AE 9 BA 18 CA 20 DA A is WELL LIKED HERE and would win in Condorcet. Count one last voter for IRV: A - B and C lose, and D loses to A. B - A, E, and B lose, and C loses to D. C or D - D wins. What Condorcet calls cycles inspire much debate. Optimum handling does deserve thought, but could be directed more as to how to resolve them. Real topic is that comparing rankings can show three or more of the best candidates are close enough to ties to require extra analysis. I claim this is a comparatively good thing - the worst candidates end up outside the cycles and it is, at least, no worse than random choice to award the win to what is seen as the best of them. Having election results in understandable format is valuable for many purposes: Condorcet records all that it cares about for any district, such as precinct, in an N*N array. These arrays can be summed for larger districts such as county or state. Also they can be published, in hopefully understandable form, for all interested. Range has less information to make available. IRV talks of recounting ballots as it steps thru discarding losers - at any rate not as convenient as Condorcet. An expected response is that these properties don't matter because they happen so rarely. To reply to that, I can think of two strategies. The first would be to count failures in simulations close to how voters would be expected to act, perhaps with a reasoning of we don't know what strategy would be like, but the results would be worse than for honesty, so these provide a lower bound. The second would be to point to real uses, like Australia's two-party domination with IRV, or Abd's argument that TTR states who switched to IRV have results much more consistent with Plurality than what used to be the case. Condorcet has no interest in being like Plurality. Its big plus over Plurality is letting voters rank those candidates they want to rank as best, etc., and using this data. Simulations are tricky - when can we honestly claim expected matches reality? -- [EMAIL PROTECTED]people.clarityconnect.com/webpages3/davek Dave Ketchum 108 Halstead Ave, Owego, NY 13827-1708 607-687-5026 Do to no one what you would not want done to you. If you want peace, work for justice. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
Dear Kristofer, you wrote: Since Condorcet is a majoritarian method (as it needs to be in order to be a good single-winner method) ... A good single-winner method *must not* be majoritarian but must elect C in the situation of 55% voters having A 100 C 80 B 0 and 45% voters having B 100 C 80 A 0 :-) Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
On Wed, 15 Oct 2008 18:49:41 +0200 Kristofer Munsterhjelm wrote: Raph Frank wrote: On 10/9/08, Dave Ketchum [EMAIL PROTECTED] wrote: If there is a near tie among three or more, they often disagree but usually get one of the leaders - matters little since the leaders were about equally deserving. It matters because IRV reinforces the 2 party system. it would be interesting to know what would be the effect of electing a parliament by condorcet voting from single seat districts. It is possible that it would also result in a 2 party system. Since Condorcet is a majoritarian method (as it needs to be in order to be a good single-winner method), the resulting parliament would also be majoritarian. This means that a party whose candidates consistently got low support in all districts would find none of those elected. But Condorcet is also a better single-winner method than Plurality, so the candidates would be better representatives of the majority. They would probably be good compromise candidates, so the parliament would be less party-based than one elected by PR methods. This might not be all that good for traditional parliaments; I don't know if the majoritarian nature would lessen competition (except in dominant-party states, where using Condorcet would be an improvement on Plurality in that respect), but it would reduce the voice of the minority. I claim the arguments here as to 2 party domination are overdone - and sometimes in a way to inspire undesirable resistance by those parties. I would rather emphasize the positive aspects: With Condorcet EVERY voter can vote preference between the two major parties, no matter what the voter's primary interest may be. With Condorcet EVERY voter can also express whatever interest may be felt as to other candidates. Note that these abilities do not conflict, though voters can emphasize whichever they choose as most important to them. With Condorcet's N*N arrays all candidates and their backers have a recording of voter interests and can and should adjust based on what they can learn of voter desires from the N*N reports as to pairs of candidates. It might be a good choice for an upper house decided to be a moderating counterweight to a populist lower house. However, based on certain assumptions, IRV is 2 party reinforcing. Also, Australia gives experimental evidence that IRV leads to a 2 party system. How much of that is due to election method, and how much as to other aspects of politics and elections? Condorcet wouldn't necessarily, so that is a good reason to at least try it. It's possible that IRV is a bad single-winner method precisely because STV is a good PR method (with many seats). In STV, one doesn't need to find a candidate that covers a large area of opinion space, since other candidates can be used to cover those areas, but in IRV there are no other positions to be used in such a manner. I'm not sure if this is the reason, but it would fit well with my simulation results that majoritarian IRV (eliminate until only k remains for council size k) is a surprisingly good PR method, at least in absence of strategy. Of course simulations can help but, too often, they are affected by biases of the simulator. -- [EMAIL PROTECTED]people.clarityconnect.com/webpages3/davek Dave Ketchum 108 Halstead Ave, Owego, NY 13827-1708 607-687-5026 Do to no one what you would not want done to you. If you want peace, work for justice. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
On 10/13/08, Aaron Armitage [EMAIL PROTECTED] wrote: Any strategically informed voter will give approval-like ratings, and will approve the top two frontrunner he likes better, as well as any candidates he prefers to that frontrunner, which means that the stated ratings will look like that regardless of the real ones and a range election will tend to produce that result regardless of how much utility voters attach to each candidate. And, of course, IRV produces the same result. Under perfect strategy, it doesn't actually matter what voting method is used. A condorcet winner would be elected every time. However, in practice, strategy only occurs at a local level. Each voter decides how to vote based on how the other voters are going to vote. This means that the optimal strategy is a Nash equilibrum. Even if C is a condorcet winner, the majority won't switch to to him under plurality if he isn't one of the top 2. However, under approval, he will get approved by a majority of the voters, as they will approve him in additiona to one of the top 2. Also, with approval polls, a condorcet winner should become one of the top 2 automatically. A system should tend towards the condorcet (or utility) winner under a process of poll - poll - ... - poll - election. A system that performs poorly under strategy fails that requirement. Voters in the (early) poll stages would be reasonably likely to give honest ratings and thus will move the result faster to the condorcet winner. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
I think his point is that he prefers any and all Condorcet methods over IRV, and probably over any non-Condorcet method. I happen to agree. --- On Sat, 10/11/08, Chris Benham [EMAIL PROTECTED] wrote: From: Chris Benham [EMAIL PROTECTED] Subject: [EM] IRV vs Condorcet vs Range/Score To: EM election-methods@lists.electorama.com, damon rasheed [EMAIL PROTECTED] Cc: Dave Ketchum [EMAIL PROTECTED] Date: Saturday, October 11, 2008, 5:14 AM Dave Ketchum wrote: Let's see: A Condorcet method finds the candidate which would beat each other candidate in a run-off election, assuming such a candidate exists. Thus such a method meets the Condorcet criterion. Having copied such from Wikipedia, don't seem like I grabbed much. Having no such candidate, we have a cycle of three or more leaders in a near tie and debate how to pick from them. Perhaps Chris is into this debate, which I agree is important but am trying to keep out of this thread, whose business is IRV vs non-IRV. Perhaps there are other exceptions. DWK Dave, Condorcet isn't decisive enough to qualify as a method. IRV is a method. All I ask is that you specify some particular Condorcet method (i.e. a method that meets the Condorcet criterion) that you are sure you prefer over IRV, so that we can compare one method with another (and not one method with one criterion). 49: A 24: B 27: CB A and C have only first-preference votes, A 49 and C 27. Is that a near tie?? Chris Benham On Fri, 10 Oct 2008 13:26:55 -0400 Terry Bouricius wrote: Dave, You are using the term Condorcet in a way that is increasingly common, but confusing to election method theorists, to mean a ranked voting method that is easiest to explain by imagining a series of one-on-one comparisons using a ranked ballot. What Chris B. was getting at is that Condorcet is a CRITERION (in fact there is also a Condorcet-loser criterion, which I think is more useful), which is used in evaluating voting methods, rather than an actual voting method itself. There are probably a dozen different voting methods that are Condorcet compliant, and many others that aren't (complying with other criteria that some believe are more crucial). The issue separating the various Condorcet methods is how you find a winner when there is no Condorcet winner. Terry Bouricius Make the switch to the world#39;s best email. Get Yahoo!7 Mail! http://au.yahoo.com/y7mail Election-Methods mailing list - see http://electorama.com/em for list info Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
Condorcet methods are the application of majority rule to elections which have more than two candidates and which cannot sequester the electorate for however many rounds it takes to produce a majority first-preference winner. If we consider majoritarianism an irreducible part of democracy, then any method which fails to elect the CW if one exists is unacceptable. Which particular method is chosen depends on what you want it to do. For example, if we at to make it difficult to change the outcome with strategic voting Smith/IRV would be best, because most strategic voting will be burying a potential CW to create an artificial cycle in the hopes that a more-preferred candidate will be chosen by the completion method. A completion method which is also vulnerable to burial makes this worse, but Smith/IRV isn't because it breaks the cycle in a way the ignores all non-first rankings. --- On Sat, 10/11/08, Chris Benham [EMAIL PROTECTED] wrote: From: Chris Benham [EMAIL PROTECTED] Subject: Re: [EM] IRV vs Condorcet vs Range/Score To: [EMAIL PROTECTED] Date: Saturday, October 11, 2008, 10:30 AM All possible Condorcet methods? - Original Message From: Aaron Armitage [EMAIL PROTECTED] To: Chris Benham [EMAIL PROTECTED] Sent: Sunday, 12 October, 2008 1:19:24 AM Subject: Re: [EM] IRV vs Condorcet vs Range/Score I think his point is that he prefers any and all Condorcet methods over IRV, and probably over any non-Condorcet method. I happen to agree. --- On Sat, 10/11/08, Chris Benham [EMAIL PROTECTED] wrote: From: Chris Benham [EMAIL PROTECTED] Subject: [EM] IRV vs Condorcet vs Range/Score To: EM election-methods@lists.electorama.com, damon rasheed [EMAIL PROTECTED] Cc: Dave Ketchum [EMAIL PROTECTED] Date: Saturday, October 11, 2008, 5:14 AM Dave Ketchum wrote: Let's see: A Condorcet method finds the candidate which would beat each other candidate in a run-off election, assuming such a candidate exists. Thus such a method meets the Condorcet criterion. Having copied such from Wikipedia, don't seem like I grabbed much. Having no such candidate, we have a cycle of three or more leaders in a near tie and debate how to pick from them. Perhaps Chris is into this debate, which I agree is important but am trying to keep out of this thread, whose business is IRV vs non-IRV. Perhaps there are other exceptions. DWK Dave, Condorcet isn't decisive enough to qualify as a method. IRV is a method. All I ask is that you specify some particular Condorcet method (i.e. a method that meets the Condorcet criterion) that you are sure you prefer over IRV, so that we can compare one method with another (and not one method with one criterion). 49: A 24: B 27: CB A and C have only first-preference votes, A 49 and C 27. Is that a near tie?? Chris Benham On Fri, 10 Oct 2008 13:26:55 -0400 Terry Bouricius wrote: Dave, You are using the term Condorcet in a way that is increasingly common, but confusing to election method theorists, to mean a ranked voting method that is easiest to explain by imagining a series of one-on-one comparisons using a ranked ballot. What Chris B. was getting at is that Condorcet is a CRITERION (in fact there is also a Condorcet-loser criterion, which I think is more useful), which is used in evaluating voting methods, rather than an actual voting method itself. There are probably a dozen different voting methods that are Condorcet compliant, and many others that aren't (complying with other criteria that some believe are more crucial). The issue separating the various Condorcet methods is how you find a winner when there is no Condorcet winner. Terry Bouricius Make the switch to the world's best email. Get Yahoo!7 Mail! http://au.yahoo.com/y7mail Election-Methods mailing list - see http://electorama.com/em for list info Make the switch to the world#39;s best email. Get Yahoo!7 Mail! http://au.yahoo.com/y7mail Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
On 10/9/08, Dave Ketchum [EMAIL PROTECTED] wrote: If there is a near tie among three or more, they often disagree but usually get one of the leaders - matters little since the leaders were about equally deserving. It matters because IRV reinforces the 2 party system. it would be interesting to know what would be the effect of electing a parliament by condorcet voting from single seat districts. It is possible that it would also result in a 2 party system. However, based on certain assumptions, IRV is 2 party reinforcing. Also, Australia gives experimental evidence that IRV leads to a 2 party system. Condorcet wouldn't necessarily, so that is a good reason to at least try it. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] IRV vs Condorcet vs Range/Score
On Thu, 9 Oct 2008 15:18:50 +0100 Raph Frank wrote: On 10/9/08, Dave Ketchum [EMAIL PROTECTED] wrote: If there is a near tie among three or more, they often disagree but usually get one of the leaders - matters little since the leaders were about equally deserving. This was part of my argument that Condorcet is better than IRV. If Condorcet sees a cycle, AB and BC and CA, we know that each got a bunch of approval and we tear our hair awarding winner, while knowing that other candidates are clear losers. If IRV awards a different winner among these three it is nothing to get excited about (of course, we throw rocks if IRV awards a win to what Condorcet sees as clear losers). It matters because IRV reinforces the 2 party system. A dangerous topic: Plurality pretty clearly does - and we also have to contend with those who like the 2 party system. I claim Condorcet does not, for voters can rank multiple candidates, having ability to vote for a 2 party candidate, especially when they expect such will win, and others they wish to back. But IRV uses the same ballot. I wonder whet might be different in Australia. Score does ratings instead of ranks - what would their excuse for claiming superiority on this topic be? it would be interesting to know what would be the effect of electing a parliament by condorcet voting from single seat districts. It is possible that it would also result in a 2 party system. Election method can matter, but so can other environment details. However, based on certain assumptions, IRV is 2 party reinforcing. Also, Australia gives experimental evidence that IRV leads to a 2 party system. Condorcet wouldn't necessarily, so that is a good reason to at least try it. -- [EMAIL PROTECTED]people.clarityconnect.com/webpages3/davek Dave Ketchum 108 Halstead Ave, Owego, NY 13827-1708 607-687-5026 Do to no one what you would not want done to you. If you want peace, work for justice. Election-Methods mailing list - see http://electorama.com/em for list info
