Re: [EM] Strategic polls in Approval
At 04:19 PM 1/7/2007, Juho wrote: >It is also possible that the three leading candidates would come from >the same party. [etc.] I find it odd that IRV proponents would claim that IRV can save money by eliminating the need for primaries, and eliminating primaries could make more likely the conditions under which IRV would select a winner against the preference of a majority. As to false polls misleading voters, if an election is close enough between three "frontrunners" I don't think it is at all obvious how voters will behave. The false poll could backfire, motivating more voters to bullet vote. After all, that is one of the rational strategies, and it directly contradicts the vote suggested by what was claimed here to be standard Approval strategy. I would prefer to think of Approval Voting *method* and then strategy as a twist on this. The basic method is to select and vote for all candidates who one judges as acceptable as winners. This is why it is named "Approval." If voters are fully honest in this, and make reasonable accomodation for the views and satisfaction of others (In other words, A is my favorite, but I know that B is preferred by many who don't like A so much, and I think of B as a reasonable choice for the office as well), then the method clearly works to find a good winner. One way to describe the process simplifies it by placing candidates on a linear spectrum and setting an Approval cutoff. In Range, this has a specific meaning I'll call the Approval cutoff the AC. However, the reform would be coming into a contentious arena, where people are accustomed to fighting for their favorite, even if the preference is actually small. They aren't going to move to Canada if B wins. They aren't going to need medication for depression, at least not for that reason So then comes strategy. Who are the likely frontrunners? The voter needs to know this because not voting for a frontrunner is likely to be a wasted vote. By definition. If the frontrunners are clear, and there are two of them, the strategy is obvious, and is what has been recommended. If there are three, i.e., the election is reasonably close to a three-way tie, in expectation, then one has a choice: Set the AC such that one of the three is approved, then add any candidates preferred to that one. or Set the AC such that two of the three are approved, then add any candidates preferred to that one. For a poll to move a candidate from not-close to frontrunner status, it would have to be drastically distorted. As I've mentioned, there are more subtle, more serious, and less provable forms of lying than this. I really don't think it's a matter for special concern. As I mentioned, it could backfire. We don't know whether distorted polls like this would improve or hurt a candidate's chance of success, because only one of the possible effects was considered, one which is thought to move the result in a direction favoring those who distorted the polling. We would also have to consider the effects which could move the vote in the opposite direction. Polls would not seriously affect the internal Range rating which underlies Approval strategy. My impression of the desirability of a candidate winning does not depend sensitively on what others think. I want a candidate to be broadly acceptable, but the difference between, say 40% acceptable and 60% acceptable would not have a large effect on my opinion of the candidate. That is, very low acceptability *would* lower my rating, and very high acceptability would raise it, but the midrange is of little effect. In the polling fraud scenario, the fraud really only nudges the relative relationships of three candidates who are probably about equally acceptable. I really doubt that it would cause me to shift my vote. election-methods mailing list - see http://electorama.com/em for list info
Re: [EM] Clone proofing Copeland
Ok, the method that I proposed is not as defensive against burial as the original one. My target was just to make the method better with sincere votes (not to seek the ultimate most strategy resistant method). I'll come back with this method and also some other variants when I find some more time (they require some more processing, I'm not quite happy with the one that I proposed either although it shows my intended direction very well). But I'll however mention some random observations that the example that you used made me think. - One could also claim that these votes are a result of strategic voting but in another way than what you described. Instead of having 49 voters that strategically changed their vote from B>A (or B) to B>C one could have had just one voter that strategically changed her vote from C>A to A>B. As a result numbers 25 and 26 were swapped and counting the first place votes gives a different result. The strategic voter was not able to get her #1 favourite but she could easily help her #2 favourite become elected. - In addition to strategies one of course also has to pay attention to the sincere votes. What would be the best candidate to elect if the votes in the example were all sincere? There is thus always a balance on how much one needs to protect against strategic voters since all such changes in the methods (in most cases) make the achieved utility with sincere votes a bit worse. If there is no significant risk of strategic voters spoiling he election => use methods that pick good candidates with sincere votes. Lots of risk => use all necessary means and modify the method so that the impact of strategies stays tolerable. Different rules apply in different voting situations (e.g. public large scale elections vs. contentious elections among the members of this list :-) ). Juho Laatu On Jan 2, 2007, at 17:37 , Chris Benham wrote: > > > Juho wrote: > >> How about "the smallest number of ballots on which some >> alternative that beats A pairwise is ranked higher than A"? >> >> Juho >> > No, that would have nothing like the same strength or resistance to > Burial. > > 26: A>B > 25: C>A > 49: B>C (sincere is B>A or B) > > The Simmons method narrowly elects A (the sincere CW), while your > suggestion easily elects > the Burier's candidate B. > > Chris Benham > > > Send instant messages to your online friends http://uk.messenger.yahoo.com election-methods mailing list - see http://electorama.com/em for list info
Re: [EM] Strategic polls in Approval
On Dec 31, 2006, at 4:55 , Abd ul-Rahman Lomax wrote: > At 01:59 PM 12/30/2006, Juho wrote: >> Im multi-party countries or if parties >> have more than one candidate that is not exceptional. > > That's right, though the latter situation requires that the party > in question have two-thirds of the electorate as supporters, > effectively. Such a party would not be likely to run two > candidates, for if it did, under some systems, it would risk losing > the election. However, with Approval, it could. And if there were a > third candidate with parity with the two from the party, party > supporters would be well advised to vote for both the party > candidates. If even half of them do, there is no chance for that > third candidate. What would be strange, indeed, would be for > significant party supporters to vote for the third candidate, and > that is exactly what it would take for the poll strategy to have an > effect It is also possible that the three leading candidates would come from the same party. Or that there would be smaller parties whose supporters would influence the outcome. The strategy may be efficient (not as certain but may work) also in the case of two candidates from one party and one from the other party in a two-party system (e.g. A and B from the same party). >> In the example it was ok if voters were uncertain of which opinion >> polls are reliable. The plotters were happy with the confusion (as >> long as they could avoid having polls where A was not among the >> leading candidates). > > How could they avoid that? They can't control all the polls, and if > they can fake polls, so can someone else. Surprise attack may work. In the next elections things could be different. It is also not nice if people stop trusting any polls because of the fear that they are somehow rigged just to make them vote wrong. It is btw also possible to advice supporters of some candidate to answer the polls in a special way. A supporters might e.g. answer that they are going to vote for A and C even if they are not. (Another interesting area for study.) > My point is that this strategem depends upon voters using a voting > strategy which is inappropriate for the three-way race that is > involved. That strategy is not designed for such races, it is > designed for races where there are two and only two frontrunners. I think the approval strategies that refer to approving candidates that are above the anticipated utility don't take position to the number of candidates. Also strategies that refer to approving one of the two frontrunners candidates do not necessarily need to exclude cases where it is not crystal clear who the two lead candidates are. Attempts to improve the optimal Approval strategy (like the one that you mentioned) are of course always welcome (zero info or others). The example only pointed out that the common optimal Approval strategies can play a part in a strategic attack (if voters are anticipated to use them). >> In the example the first (correct) poll showed that A and B had more >> support than C (but only so much that the A supporters could claim >> that also C could be a lead candidate). > > Right. So all are close to winning. Now, is this "first preference" > polling or "approval" polling? I didn't take position on that but both cases work. Approval polls are more accurate when asking opinions before an Approval election. Preference order of the approved candidates would provide additional information. > I don't think that the analysis of the stratagem's effect was > thorough. To be thorough, one should consider preference strengths, > they affect how the voters will respond to the misinformation. It was not thorough (just a description of the vulnerability). I made some calculations also with approving candidates that are above the expected utility of the election and the strategy seemed to work at least with some reasonable personal utility assumptions (e.g. utilities 2-1-0 for all voters). > Now, if voters have a preferred candidate, I'd think they would > listen to that campaign's releases about how the election was > going. They would not be terribly likely to be influenced for > strategic voting purposes by releases from the campaign of another > candidate, not even by supposedly public, disinterested polling > organizations. The A supporters should not hide their involvement in the poll if possible. But also a poll signed by A supporters may have sufficient impact in a close race. > I don't think it is possible to distort the polls sufficiently that > a rational voting strategy would be seriously affected. Small changes are sufficient if the margins are small. Of course all kind of propaganda will be distributed. Utilizing the Approval default optimal strategies is just one of the tricks, not necessarily the decisive one. In the example the A supporters man
Re: [EM] Election methods in student government...
I support raphfrk's thoughts that the basic methods might be the best choice. Open list and PR-STV are two quite well working basic PR methods. Raphfrk proposed also asset voting. Also that one is quite simple and natural. It may add some "asset trading", which might be a bad thing in this environment that I understood was quite interested in plotting. Well, maybe they'd really like that second negotiation round of asset voting and be happy to use this method. Or alternatively they should not be given the chance to start this kind of horse trading. I have also another less common method that I have promoted on this mailing list. Open list methods can be extended to cover also hierarchical candidate settings. The lists are no longer lists, so "tree voting" is a better name for this method. The candidates (and parties and other groupings) thus agree a tree-like structure where candidates are leaves and branches of the tree may have descriptive names (party names, party branches, interest groups). Voters vote simply one of the candidates. The seats are allocated to the branches of the tree (based on the number of votes received by each branch) starting from the root using some suitable PR allocation method. This process is then repeated towards the smaller branches until all the seats have been allocated to the candidates in the leafs. Tree voting gives candidates some more information on the candidates than traditional open list does (from party alliances to small interest groups). Also the division of seats within each party is more fair (not plurality based but proportional also within parties and party alliances). Tree voting doesn't allow giving her personal inheritance order in the ballot (in STV style). But the candidate given order of inheritance (in the form of the tree) is there, and it may reflect the true thoughts/intentions of the candidates quite accurately (=not much space for the candidates to tell each voter group that the candidate would promote especially their values). In elections where there are numerous candidates expecting all voters to know the candidates well enough to give them a STV like preference order may be too much. In elections where all candidates are well known that might be ok. Juho Laatu On Dec 21, 2006, at 14:34 , [EMAIL PROTECTED] wrote: > > From: [EMAIL PROTECTED] > > > > Anyway, I have been investigating alternate systems for single- > winner > > elections and (especially) multi-winner elections. Party list is > out > > - the less rigidly-defined party structure makes it even less fair > > that it would be in a national election. > > There is a system called open party list. Basically, the voter votes > for 1 candidate. The party that that candidate represents gets the > vote > and the seats are split on that basist between the parties. However, > the party member that actually fills each seat is determined by how > many > votes the candidate obtained for the party, e.g. the party's highest > vote getter gets the first party seat and so on down until all the > party > seats are filled. > > This allows the voters to choose the parties but also choose which > party member gets elected. > > > > I have also investigated STV (and IRV for single-winner) > However, the > > lack of monotonicity is quite troubling - the fact that you can help > > elect a candidate by ranking them LOWER seems almost undemocratic. > > In the multi seat case, I don't think PR-STV is that bad. > > > This, coupled with the fact that the current system *replaced* STV > > some 20-odd years ago, dampens my enthusiasm for that method a bit. > > That doesn't mean that STV is bad, it just means that it is bad for > the majority. Any PR system is bad for the majority. > > Look at what the new system actually does ... it give most of the > seats to the majority party/faction. Who decided the current system? > Presumably, it was the majority party/faction. > > > I have also seen plenty of other election methods that look > interesting > > - Concordet methods especially. However, these methods are quite > complex > > and don't have any good multi-winner variant (there is CPO-STV, > but it is > > extremely complex and is still non-monotonic). > > I would suggest asset voting as a really simple way to get PR. > > In its most simple form, each voter votes for 1 candidate. Any > candidate > who gets the quota is elected and can transfer his excess to any > other candidate. > All the other candidates can also transfer votes in order to bring > one of > them to the quota. > > > Right now, I'm kind of at a loss as to what the best voting > system would be. > > It depends on your objectives. There is no 'best' system. > > > It's obvious that the current system isn't it > > Yeah, it does seem pretty bad. > > > I also don't like the idea of using a system that is so complex that > > it can't be reasonably explai
