Re: [EM] Simple illustration of center-squeeze effect in runoff voting
Abd ul-Rahman Lomax wrote: At 05:41 AM 1/21/2009, Kristofer Munsterhjelm wrote: My usual argument against Approval (in favor of something more complex) is this: Say there are three viable parties (if there will be only two, why have Approval in the first place?). You support A B C. If A is in the lead, you can approve of A alone. If A's a minor party, then you should approve of both A and B. But if the parties are close, then it may not be clear who you should approve - if A's slightly too low (and the important contest is A vs C), then voting only A will split the vote and may cause C to be elected instead of B. If A's not that low (and the important contest is A vs B), then voting both A and B will cancel your vote for A with your vote for B. It becomes more difficult the closer the parties are in support, and polling errors could cause further problems. Approval works within a multiple election environment, classically it wasn't used with anything other than a true majority requirement, and it was probably expected that initial votes would be bullet votes. Approval as a deterministic method that must find a winner with a single ballot is simply a more sophisticated, improved form of Plurality, as is IRV, but Approval is far simpler. The scenario described is unusual in partisan elections, but I certainly wouldn't propose Approval as an ideal election method. It is merely the largest improvement that can be accomplished with such a minimal shift from Plurality: just start to count all the votes. Dump the no-overvoting rules. I'll say again: if there are more than two viable parties, the this could happen. If there will be only two viable parties, why use Approval? As a concrete example, consider the 2002 French Presidential election. You support Bayrou - are you going to approve of Jospin alone, or of both Jospin and Chirac? You probably don't know that the Le Pen supporters are as powerful as they are, so you approve only of Jospin. Then the runoff picks Le Pen and Chirac. If there had been no runoff, Chirac would have won outright, which is better than Le Pen, but not what you wanted. Of course, you may say that if the method was approval, others would have voted in styles different from bullet-voting, but I'm trying to show a problem; and if it's true what you say, that most people will bullet vote, then the scenario is all the more plausible. With a majority requirement, Approval gets much better. Then we'd want to look at runoff conditions. Approval should *ameliorate* -- not entirely eliminate -- Center Squeeze. Approval theorists have largely failed to anticipate, I think, the degree of bullet voting that will occur. In Bucklin, which is Approval with some degree of Later No Harm protection (not absolute by any means), bullet voting was seen with most voters. But most voters, by definition, support frontrunners! I prefer Bucklin for public elections because it remains simple to canvass, resembles Approval in some good ways, and still allows voters to express an exclusive first preference. I'd allow multiple voting in all ranks, so a three-rank Bucklin ballot could be quite expressive. (Traditional Bucklin, as in Duluth, Minnesota, only allowed multiple votes in the third rank.) An aside: you like Bucklin. Have you considered MDDA? Like ER-Bucklin, it also passes the favorite betrayal condition (meaning, you don't have to vote someone below favorite if that person *is* your favorite). MDDA also meets SFC, which means that if there's a coordinated majority, that majority needs not to falsify any preference. It acceps truncated ranked ballots (like Bucklin). MDDA works like this: Ranked ballots, all ranked are approved. Before the Approval phase, check for each candidate if there's some other candidate that is ranked above that candidate on a majority of the ballots. If so, disqualify the candidate ranked below. Do this for all candidates for which this is true, unless that would eliminate all candidates. The Approval winner of the remaining candidates wins. Also, regarding bullet voting: given my French example above, I should rationally argue that bullet-voting is prevalent, but I'll do otherwise. Both the Burlington and the SF data shows that bullet-voting is not as common as you say. The raw ballot images for SF say that some people bullet-voted by ranking the same candidate first, second, and third - that works like bullet-voting because if that candidate is X, and X is disqualified, X is removed from all positions of the ballot, hence he's no longer in the running. Similarly, if X wins, X is then removed from the ballots, which means all positions of the virtual bullet ballot have been invalidated. Now you may say that SF voters aren't clever enough on the whole to bullet-vote this way. That leaves Burlington; and I suppose you could say that Burlington is unrepresentative - unlike most areas of the
Re: [EM] The structuring of power and the composition of norms by communicative assent
Juho Laatu wrote: Yes, it is good to facilitate mutual discussion better. My aim with this discussion is to study if one can combine that with the good old privacy / secret vote principles. The most significant combo (I think) is that of the existing general electoral systems of the state (private/secret ballot), and the new primary system of the public sphere (public/open ballot). There's a synergy between them - both together are better than either would be alone. Likewise for state legislative voting (closed, inaccessible) and public voting on norms (open, accessible) - synergy there too. So we rationalize society's voting systems. But can private voting fit in the public sphere? There are at least two practical problems: i) Given the protections of free speech, there is no way to generally enforce a secret ballot I see three alternative approaches (for each individual voter) here. 1) The vote is forced secret. The voter can tell how she voted (=freedom of speech). But she can not prove to the coercer or buyer how she voted. 2) The voter can choose if her vote is public or secret. She can also tell what her secret vote was. 3) The vote is public. What I mean is that also enforced secrecy and free speech can be combined. Not in the public sphere - neither (1) nor (3) is enforceable - only (2) is allowed. It is the nature of the public sphere, and part of the legitimacy it confers on the process. More on that later... I think current systems rely on private voting and public discussion (although different than the proxy based discussion). It may be possible to enrich this with better mutual discussion / delegable voting rights without sacrificing secret votes / privacy. Yes, it might be *possible*, but I think it would be difficult in practice (and not ideal in principle) to do so within a *single* voting system. The most rational design is separate, special purpose systems (primary and general) that work together. I don't see the need of a representative / proxy to know who her voters exactly are to be crucial. In some aspect it is better that she doesn't know (no vote buying, services to those that voted, no hard feelings against those that this time voted someone else etc.). The (secret) voters on the other hand will get more power when they can let several representatives / proxies understand that they got or may get the vote :-). All of this is easier, more natural, if agreement (voter for candidate/delegate) is *actually* expressed. Then it's more human. We weren't *built* to deal with the strange paradox of private expression (collective mass opinion). There's no natural correlate for it. Yes. Having a rich hierarchical discussion structure is one key benefit of the proxy structure. (Also secret voters may participate. Some of the proxies are low level and nearby in any case.) Yes, and there *will* be secret voters in the public primaries. We cannot disallow secret ballots, and enforce purity. Nor would it even be ideal - some allowance for extreme situations is better. But hopefully there will not be *too* many private voters, as they will not be able to participate properly (more on this later). Yes, continuous talk may improve the discussion. This topic has however also the other side. One reason behind terms of few years is that this way the representatives will have some time to work in peace. Continuous voting may also make the system more populist (no tax raises ever since all those representatives might be kicked out right away, without the calming period before the next elections). There is no direct action as a consequence of primary results. The public cannot *force* anything. All power remains with the administration, the general electoral systems (non-continuous), and the legislative assembly (inaccessible to public). But those systems are *informed* by the public system, and this can amount to effective control. It sounds paradoxical, because we've separated control from power, but it's actually the rational thing to do. In engineering theory, the control/guidance systems and the power systems are kept well separate from each other, and their designs are radically different. The pilot in the cockpit does not reach his hands into the engine turbines, or forcefully move the elevator, ailerons, and rudder. The cockpit is fitted with low power instruments and controls, at a safe distance from the engines etc. It is possible to have also some hysteresis in the system. This allows for example short protests by the voters and allowing them to still change their mind before the representative will be kicked out. In some systems and at some levels it however may not matter if the representatives / proxies change frequently. Hysteresis and other decoupling is provided by the separation of the two types of voting system - the system of public controls (as it were)
Re: [EM] Generalizing manipulability
Juho Laatu wrote: I try to summarize my comments in the form of some rough definitions. A simple method requires 1) a 'simple' method to convert honest preferences into optimal votes A zero-info method requires 2) this method may not use info about other voters, but still be able to convert honest preferences into optimal votes A non-manipulable method requires 3) it is in everyone's interests to use the default method to convert honest preferences into optimal votes (I didn't cover the if everyone else uses this method case.) These definitions allow also e.g. Approval to be categorized as (close to) simple, not zero-info and non-manipulable. One more definition to point out one weakness of Approval. A decidable method requires 1) a method to convert honest preferences into an unambiguous optimal vote The point is that the there should be no lotteries that may lead also to unoptimal votes but the best vote should be found in a deterministic way. Approval fails this criterion since picking the correct number of approved candidates is sometimes tricky (when there are more than two strong candidates). Since all ranked methods are vulnerable to strategy, what constitutes an optimal vote depends on the votes of everybody else. Thus no such method can be either of the above, and any simple method (by the definition) must also be non-manipulable, since to discover the optimal vote otherwise, you'd have to know the votes of potentially everybody else. The definitions you gave could be used for zero info strategy. For instance: Simple zero-info: The optimal zero-information strategy is simple to determine. Dominant zero-info: If everybody uses zero info strategy, and the method doesn't output a tie, no single voter could gain by changing his vote to something else. And there's also the usual zero-info strategy criterion: No zero-info strategy: The optimal zero information strategy is a sincere vote. No zero-info strategy implies simple zero-info. Dominant zero-info is vaguely similar to SDSC, though the latter deals with counterstrategies. Dominant zero-info may also be too strong: consider a situation where the voters produce a tie minus one vote (where a certain ballot can produce a tie); then, if the final voter prefers a candidate that would be ranked lower to one that would be ranked higher, he can construct a vote that leads to the two being tied. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] The structuring of power and the composition of norms by communicative assent
Juho Laatu wrote: d) voting on laws, too I read this as allowing individual voters to vote directly too, without any proxies between them and the decisions (on laws and on anything). Quite OK but I have some concerns on what will happen in the tax raise questions. It is possible that the society would spend more than save. One could set some limits on the number of levels. One could e.g. allow only proxies with n votes to vote in certain questions. Use of hysteresis could help making the role of proxies of different levels clear (last minute decisions or alternative direct and proxy votes would be more complex). The proxy systems may allow (also for other reasons) different proxies or direct voting to be used for different questions. Some idea of what this would lead to can be gathered from states with initiative and referendum, where the citizenry can force a referendum or the passing of a law. It seems to work in the United States states that have them, and also in Switzerland, though the circumstances there are more complex. On the other hand, one could argue that the signature requirements to start the referendum process constitutes a form of hysteresis: because starting the process requires some effort, the system won't oscillate wildly. The real trick is to find the balance between something that oscillates and something that doesn't respond at all - and that's not a problem that's particular to politics, but appears in various guises in all kinds of systems involving feedback. Set the PID controller wrong and it's off to hunting land... Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] Why the concept of sincere votes in Range is flawed.
At 09:51 AM 1/23/2009, Jobst Heitzig wrote: I did not mean to say the voter has no opinion. He may well hold the opinion that, say, A is much better than B in some respect, and B is much better than A in another respect, so that neither is A preferable to B nor B to A nor are they equivalent (equally preferable). This is just an ordinary case of what some people pejoratively call incomplete preferences. Or the voter may hold the opinion that A is better than B in two of three respects, B is better than C in two of three respects, and C is better than A in two of three respects, so that A is strictly preferable to B, B to C, and C to A. This would be a case of complete but cyclic preferences. Or, even more simple, A and B may just be completely equivalent, so that neither is preferable to the other. In all these cases, a favourite is inexistent, not just unknown. Yes. However, this problem actually doesn't afflict Range Voting, it is a *voter* problem. In the end, the voter risks his or her vote, spends it. How much of the voter's vote will the voter risk? Put it another way. Suppose the voter can decide the outcome of the election by bidding. The voter still has the problem of choosing between A, B, and C, but the choice *between* them isn't forced. I.e., the voter can bid equally for them. Now, in real elections, the voter has something that the voter can spend as a bid. It's a vote, one single vote. How the voter will spend this depends not only on the voter's preferences and preference strengths, but also on probabilities of success. That's what VNM utilities are: bids in lotteries, determined not only by absolute utilities, but also by estimated relevance. The voter doesn't normally want to spend the vote discriminating between moot candidates. But if the voter doesn't care that much about which of the frontrunners is elected (perhaps they are all equally bad, or equally good, in the voter's eyes), then the voter may indeed invest the vote in moot pairwise races. To understand what I mean by investing the vote, imagine a Range election with three candidates, A, B, and C. The voter has one full vote to invest in influencing the outcome. How does the voter vote? It's a fairly straightforward problem in game theory. Let R(A) be the range rating of A, similarly with B and C. Arrange the candidates in preference order, and we'll assume that they've been named in that order, i.e., ABC. A strategic vote is, first of all, a normalized one, so R(A) equals 100% and R(C) equals 0%. Actual votes are V(A), V(B), V(C). The vote is distributed as follows: V(A:B) = R(A) - R(B), V(B:C) = R(B) - R(C). The Range constraint is that the votes are all in the range of 0 - 100%, and V(A:B) + V(B:C) is not greater than 1 full vote, i.e., 100%. If the vote is normalized, the sum of preference strengths is 100%. V represents preference strengths between adjacent candidates in the Range spectrum. If there is a cycle as described by Jobst, how does the voter express the votes? We face this problem all the time with choices; in the end, a particular choice is worth something to us; the worth is not cyclic; we do not, in fact, do Condorcet analysis, we do Range analysis. With VNM utilities; we don't invest our resources in moot choices. We might not even consider them, but if we do, we don't shift our non-moot votes, or if we shift them, we shift them only a little. The voter determines the vote to invest by effectively multiplying the value of a pairwise election, then multiplying it by the probability that the vote is effective. (It's a relative probability, the actual probability is very low in public elections unless there are very few voters.) Voters already do all this; voters don't actually do the math, or at least such voters would be rare. We vote this way in plurality; complicating it is that we have other values to satisfy besides election results. However, that's covered in the calculations, if they are complete. It's all about how much the voter cares about an election result. If the voter is indifferent between A and B, but strongly prefers C to either of them, and A and B are frontrunners, that a vote in the A/B pair is the only effective vote, as we would normally look at it, i.e., only A or B can realistically win, that the probability of an A result is close to one can't overcome the value of the election pair, which I just expressed as zero. But wouldn't this work on the other pair, but in reverse, the value is 100% for C, but the probability of success is zero? Sure it would, if the voter doesn't have a value for simply having contributed to the vote count for C. Voters who don't have a high value for that *don't vote.* However, voters *do* value voting for candidates who can't win, we know that. So insignificant value between A and B, and high value in voting for C, leads to a vote of 0, 0, 100. And the vote is sincere. Further,
Re: [EM] Beatpath GMC compliance a mistaken standard?
Kevin, I can't see what's so highly absurd about failing mono-append. It's basically a limited case of mono-raise, and one that doesn't seem especially more important. Is it absurd to fail mono-raise? The absurdity of failing mono-append is compounded by the cheapness of meeting it. As with mono-add-plump the quasi-intelligent device is given simple and pure new information. Being confused by it is simply unforgivable *stupidity* on the part of the quasi-intelligent device. Regards mono-raise, I would say that failing it is obviously 'positionally absurd' and 'pairwise absurd' but perhaps not 'LNH absurd'. We know that it isn't absurd in the sense that mono-add-plump and mono-append is, because it is failed by a method that has a maximal set of (IMO) desirable criterion compliances . Can I take it then that you no longer like CDTT,Random Ballot, which does award a probability pie? Sure. Does your question mean that this really is how you view the difference between CDTT and Mutual Majority, is in terms of the candidates of the winning set sharing a probability pie? Not exactly. No-one has ever suggested MM,Random Ballot as a good method and few have suggested that sometimes the clearly most appropriate winner is not in the MM set (as I have regarding the CDTT set). The criterion/standard is an end in itself. Not everything is about the strategy game. Higer SU with sincere voting and sparing the method common-sense (at least) difficult -to-counter complaints from the positional-minded are worthwhile accomplisments. This strikes me as an unusual amount of paranoia that the method's results can't be explained to the public's satisfaction unless it's similar to Approval. It isn't just the public. It is myself wearing my common-sense positional hat. And it isn't just Approval, it's 'Approval and/or FPP'. Chris Benham Hi Chris, --- En date de : Jeu 15.1.09, Chris Benham cbenha...@yahoo.com.au a écrit : Kevin, You wrote (12 Jan 2009): Why do we *currently* ever bother to satisfy difficult criteria? What do we mean when we say we value a criterion? Surely not just that we feel it's cheap? When simultaneously a criterion's satisfaction's cost falls below a certain level and its failure reaches a certain level of absurdity/silliness I start to lose sight of the distinction between important for its own sake and very silly not to have because it's so cheap. Mono-add-plump (like mono-append) is way inside that territory. I see. I don't think I value criteria for this sort of reason. If I insist on a criterion like Plurality, it's because I don't think the public will accept the alternative. And these two criteria are relative, so that in order to complain about a violation you have to illustrate a hypothetical scenario in addition to what really occurred. I can't see what's so highly absurd about failing mono-append. It's basically a limited case of mono-raise, and one that doesn't seem especially more important. Is it absurd to fail mono-raise? If you need to identify majorities, then the fact that a ballot shows no preference between Y and Z, is relevant information. In my view a voting method *doesn't* need to specifically identify majorities, so it isn't. (The voting method can and should meet majority-related criteria 'naturally' and obliquely.) But we aren't even talking about voting methods, we're talking about sets. You have basically criticized Schulze(wv) even though it naturally and obliquely satisfies majority-related criteria. But even if the quasi-intelligent device is mistaken in treating them as relevant, then that is a much more understandable and much less serious a blunder than the mono-add-plump failure. Ok. I still don't really see why, or what makes the difference. Imagine the quasi-intelligent device is the captain of a democracy bus that takes on passengers and then decides on its course/destination after polling the passengers. Imagine that as in situation 1 it provisionally decides to go to C, and then as in situation 2 a group of new passengers get on (swelling the total by about 28%) and they are openly polled and they all say we want to go to C, and have nothing else to say and then the captain announces in that case I'll take the bus to B. Would you have confidence that that captain made rational decisions on the most democratic (best representing the passengers' expressed wishes) decisions? I and I think many others would not, and would conclude that the final B decision can only be right if the original C decision was completely ridiculous. Or would you be impressed by the captain's wisdom in being properly swayed by the new passengers' indecision between A and B? However I answer doesn't make any difference, because the question is why this crosses the boundary of clear badness while failures of mono-add-top and
Re: [EM] Simple illustration of center-squeeze effect in runoff voting
At 06:47 AM 1/23/2009, Kristofer Munsterhjelm wrote: I'll say again: if there are more than two viable parties, the this could happen. If there will be only two viable parties, why use Approval? You've missed something crucial: Approval is being proposed for public partisan elections where there are only two viable parties. When there are more than two, Plurality breaks down very badly. Approval fixes the spoiler effect. Where a majority is required, it also would improve primary results, and used in a runoff it would, in unusual situations, provide a simple solution to the write-in problem. But Bucklin probably does both of these better. Approval is proposed, by me, because of its terminal simplicity. Essentially, an old error is eliminated, the assumption that voters won't or shouldn't equal rank. As a concrete example, consider the 2002 French Presidential election. You support Bayrou - are you going to approve of Jospin alone, or of both Jospin and Chirac? You probably don't know that the Le Pen supporters are as powerful as they are, so you approve only of Jospin. Then the runoff picks Le Pen and Chirac. If there had been no runoff, Chirac would have won outright, which is better than Le Pen, but not what you wanted. Absolutely, understood very well. Bucklin would do better. For reasons that escape many voting systems experts, Range would do better. Condorcet would do better, but with a cost. Hybrid Range/Bucklin/Condorcet would be best, but every complexity makes implementation less likely. At one point it was fairly widely discussed, and just about everyone who wasn't stuck with IRV agreed that Approval was an improvement. The only objections we see are based on Voters won't like it, but Bucklin, which is a kind of approval voting, but ranked, was very popular with voters. Sure, many of them bullet voted, but this is a rational and effective vote for most voters; the extra votes are only required, really, for a few. Bucklin answers the objection of many to Approval: with Approval, they can't express their preference for one candidate *and* approve others. That's simple to fix! Just use a ranked ballot, as Bucklin did, then bring in lower ranks only when a majority isn't found in the first rank. And hybrids can get much better; but we need to keep one thing in mind. Plurality usually works. Plurality usually elects the Condorcet winner. Etc. Advanced voting systems may only affect one election out of ten or so. (Depends greatly on many factors; in some situations, typically with many candidates, plurality breaks down badly, *unless* it's plurality with a majority requirement, *and* runoffs don't involve candidate eliminations. That's actually standard Robert's Rules election practice. Some candidates withdraw and voters shift their votes according to the previous results. *They don't want to keep voting forever!* Eventually a compromise is found. (And, naturally, this is typically done when the voters are present at a meeting together.) Of course, you may say that if the method was approval, others would have voted in styles different from bullet-voting, but I'm trying to show a problem; and if it's true what you say, that most people will bullet vote, then the scenario is all the more plausible. With a majority requirement, Approval gets much better. Then we'd want to look at runoff conditions. Approval should *ameliorate* -- not entirely eliminate -- Center Squeeze. Approval theorists have largely failed to anticipate, I think, the degree of bullet voting that will occur. In Bucklin, which is Approval with some degree of Later No Harm protection (not absolute by any means), bullet voting was seen with most voters. But most voters, by definition, support frontrunners! I prefer Bucklin for public elections because it remains simple to canvass, resembles Approval in some good ways, and still allows voters to express an exclusive first preference. I'd allow multiple voting in all ranks, so a three-rank Bucklin ballot could be quite expressive. (Traditional Bucklin, as in Duluth, Minnesota, only allowed multiple votes in the third rank.) An aside: you like Bucklin. Have you considered MDDA? Like ER-Bucklin, it also passes the favorite betrayal condition (meaning, you don't have to vote someone below favorite if that person *is* your favorite). MDDA also meets SFC, which means that if there's a coordinated majority, that majority needs not to falsify any preference. It acceps truncated ranked ballots (like Bucklin). MDDA works like this: Ranked ballots, all ranked are approved. Before the Approval phase, check for each candidate if there's some other candidate that is ranked above that candidate on a majority of the ballots. If so, disqualify the candidate ranked below. Do this for all candidates for which this is true, unless that would eliminate all candidates. The Approval winner of the remaining candidates
Re: [EM] The structuring of power and the composition of norms by communicative assent
On Fri, 23 Jan 2009 10:22:13 -0500 Michael Allan wrote: Juho Laatu wrote: Yes, it is good to facilitate mutual discussion better. My aim with this discussion is to study if one can combine that with the good old privacy / secret vote principles. The most significant combo (I think) is that of the existing general electoral systems of the state (private/secret ballot), and the new primary system of the public sphere (public/open ballot). There's a synergy between them - both together are better than either would be alone. Likewise for state legislative voting (closed, inaccessible) and public voting on norms (open, accessible) - synergy there too. So we rationalize society's voting systems. But can private voting fit in the public sphere? There are at least two practical problems: i) Given the protections of free speech, there is no way to generally enforce a secret ballot I see three alternative approaches (for each individual voter) here. 1) The vote is forced secret. The voter can tell how she voted (=freedom of speech). But she can not prove to the coercer or buyer how she voted. 2) The voter can choose if her vote is public or secret. She can also tell what her secret vote was. 3) The vote is public. What I mean is that also enforced secrecy and free speech can be combined. Not in the public sphere - neither (1) nor (3) is enforceable - only (2) is allowed. It is the nature of the public sphere, and part of the legitimacy it confers on the process. More on that later... I get dizzy on public vs private as used here, but have to disagree on some of the above. True secret voting - important to protect a voter's vote from being known: A society can use a ballot box with black and white balls, especially for deciding whether to accept a new member. There is NO record to protect or lose as to who voted black. Lever voting machines can be used in public elections. At least originally these were as secret, though all kinds of cheating now becomes possible. Paper absentee ballots can be handled in a way that, if done properly, maintains secrecy. The envelope has the voter's name. The ballot is forbidden to identify the voter in any way, and is void otherwise. When the envelope is opened the ballot is placed in a stack of such without looking at content. Signing petitions is generally non-secret - with this known to the signers. Speech is only occasionally kept secret - courts and legislatures and societies choose when they need this. ... Proxies? There is need for a verifiable record as to how many votes a proxy can cast. -- da...@clarityconnect.compeople.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] Simple illustration of center-squeeze effect in runoff voting
On Fri, 23 Jan 2009 12:47:53 +0100 Kristofer Munsterhjelm wrote: Abd ul-Rahman Lomax wrote: At 05:41 AM 1/21/2009, Kristofer Munsterhjelm wrote: My usual argument against Approval (in favor of something more complex) is this: Say there are three viable parties (if there will be only two, why have Approval in the first place?). You support A B C. If A is in the lead, you can approve of A alone. If A's a minor party, then you should approve of both A and B. But if the parties are close, then it may not be clear who you should approve - if A's slightly too low (and the important contest is A vs C), then voting only A will split the vote and may cause C to be elected instead of B. If A's not that low (and the important contest is A vs B), then voting both A and B will cancel your vote for A with your vote for B. It becomes more difficult the closer the parties are in support, and polling errors could cause further problems. Approval works within a multiple election environment, classically it wasn't used with anything other than a true majority requirement, and it was probably expected that initial votes would be bullet votes. Approval as a deterministic method that must find a winner with a single ballot is simply a more sophisticated, improved form of Plurality, as is IRV, but Approval is far simpler. The scenario described is unusual in partisan elections, but I certainly wouldn't propose Approval as an ideal election method. It is merely the largest improvement that can be accomplished with such a minimal shift from Plurality: just start to count all the votes. Dump the no-overvoting rules. I'll say again: if there are more than two viable parties, the this could happen. If there will be only two viable parties, why use Approval? Count of parties is not useful. Usually there are only two leading candidates and election method matters little. Trouble is, occasionally there are more leading candidates, as in the example below, and, THEN, methods matter. Whether this was truly center-squeeze or not, the idea applies - two candidates off to the side, each with a bunch of dedicated followers, and a bunch of candidates sharing the center votes. As a concrete example, consider the 2002 French Presidential election. You support Bayrou - are you going to approve of Jospin alone, or of both Jospin and Chirac? You probably don't know that the Le Pen supporters are as powerful as they are, so you approve only of Jospin. Then the runoff picks Le Pen and Chirac. If there had been no runoff, Chirac would have won outright, which is better than Le Pen, but not what you wanted. Of course, you may say that if the method was approval, others would have voted in styles different from bullet-voting, but I'm trying to show a problem; and if it's true what you say, that most people will bullet vote, then the scenario is all the more plausible. As with Approval, Condorcet voters have choices: Dedicated followers of the two on the side likely bullet vote. Center voters properly vote for a bunch of center candidates - hoping one such will win. ... -- da...@clarityconnect.compeople.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
