It does sound like this system will have better resistance to the Chicken Dilemma. I can support it, assuming noone finds any fatal flaws.
I've thought about the top-down vs. bottom-up question and the naming for a while and can't form a strong opinion. Let me think about it some more. I heard that a big reason FairVote has been moving to the "ranked choice" branding is that it fits better with their long-term strategy, STV. ~ Andy On Fri, Jun 14, 2013 at 5:52 PM, Jameson Quinn <jameson.qu...@gmail.com>wrote: > So. Abd and I now agree that a Bucklin system which uses just the > above-median votes to break ties is probably the best first step towards > median voting. I'd like to get the details worked out, so we can stop using > different terms ("Bucklin", "MJ", "GMJ") and settle on a single > clearly-defined proposal. I'd love to hear what others feel about these > issues (though this isn't really the place for debating whether some other > class of voting system, such as Score or Condorcet or whatever, is better > or worse than Bucklin/Median systems in general). > > 1. How to best express the system? Two equivalent definitions: > > - *Top-down*: "Count the votes at the highest grade for each > candidate. If any one candidate has a majority, they win. If not, add in > lower grades, one at a time, until some candidate or candidates get a > majority. If two candidates would reach a majority at the same grade level, > then whichever has the most votes above that level wins. If there are no > votes above that level, the highest votes at or above that level wins." > - *Bottom-up*: "Count the votes at the lowest grade against each > candidate. If any candidates have a majority against, eliminate them from > consideration. Continue adding in the next-lowest grade, until there is > just one or zero candidates left. If there's one left, they win. Otherwise, > if the last few candidates are eliminated together, choose whichever of > that group was eliminated by the smallest majority against." > > > 2. How many rating/grade/rank levels should be used, and how should they > be labeled? I'd suggest the following 5, along the lines of something Abd > proposed: > > A: Unequivocal support > B: Probable support (unless there's a candidate with majority "A" support) > C: Neutral (support or oppose, depending on other candidates' results) > D: Probable opposition (unless all other candidates have majority "F" > opposition) > F: Unequivocal opposition > > (I've relabeled the categories to help clarify their strategic meaning; > for instance, I changed "strong" to "unequivocal") > > I would also be open to having blank votes count as "E" rather than "F", > but I think that's probably an unnecessary complication to begin with. > > 3. What should we call this system? Abd seemed happy with "Instant Runoff > Approval Voting". I'd be fine with that too, but before we settle on that, > we should look at the downsides: > > - FairVote has been moving away from "Instant Runoff / IRV" and > towards "ranked choice/ RCV" in recent years. I don't know all of their > reasons, but I suspect it is partially to do with the legalism of ballot > initiative language. That is, IRV is technically neither instant nor a > runoff, though it is certainly close on both counts. > - It could lead to confusion between IRAV and IRV. That has its > upsides — piggybacking on FairVote's existing publicity — but also its > downsides — as we know, IRV is actually a pretty flawed system. > > So I think we should have a poll with various options (using the system > itself to rate the options, of course). I'll start out with some proposals > and my votes: > > -IRAV: B > -Descending Approval Threshold (DAT) Voting: A > -Descending Approval Threshold Adjudgment (DATA voting): B > -Majority Approval Threshold (MAT; note that the M could also be > backronymmed to "Median"): A > -Bucklin: F (not that we shouldn't say that this system is a Bucklin > system, just that that shouldn't be our only name for it) > -Bucklin-ER or ER-Bucklin: D (has already been used for other systems, not > a descriptive name) > -Graded Approval Threshold (GAT): C (Not bad, but not great) > -Majority Assignment of Grades (MAG): C (ditto) > -Graded Majority Approval (GMA): B (this one seems simple and descriptive) > > Note that all of the above names could, in principle, apply to almost any > Bucklin system; but whichever one we pick, we'll arbitrarily define it as > being this system in particular. > > Abd and anyone else who has an opinion: please vote among the above > options. > > Jameson > > > 2013/6/13 Abd ul-Rahman Lomax <a...@lomaxdesign.com> > >> At 03:53 PM 6/13/2013, you wrote: >> >>> I just had a minor realization. As I said to Abd, his Bucklin-ER (as I >>> understand it) has slightly less resistance to the chicken dilemma than >>> GMJ, because the Bucklin-ER tiebreaker effectively ends up focusing >>> slightly below the median in the grade distribution, while GMJ focuses on a >>> region balanced around the median. Well, why not take that in the other >>> direction? Consider the following Bucklin system, tentativlely named: >>> uı|ʞɔnq-ᴚƎ: >>> >>> >>> Count the votes at the highest grade for each candidate. If any one >>> candidate has a majority, they win. If not, add in lower grades, one at a >>> time, until some candidate or candidates get a majority. If two candidates >>> would reach a majority at the same grade level, then whichever has the most >>> votes above that level wins. If there are no votes above that level, the >>> highest votes at or above that level wins. >>> >> >> Now, this is familiar to me. I'm not searching right now, but I do think >> that this may have been a tiebreaker method with traditional Bucklin. >> >> Here, what it does is to award a win based on a plurality in the prior >> rank, but with the approval of a majority as shown by the next rank of >> approvals. Way cool. It incentivizes expressing preferences with some >> strength. If candidate count increases to that the limitation to three or >> four ranks is a problem, the number of ranks (ratings) may be increased. >> >> Now consider a chicken dilemma where Y and Z must cooperate to defeat X. >>> If a Y voter rates Z at the second-to-bottom grade, then further strategy >>> simply will not help unless Z's median falls to 0 — which would mean >>> risking ann X win if Z's voters are similarly strategic. This is a >>> stronger, and more-simply-argued, bulwark against the chicken dilemma's >>> slippery slope than GMJ's. >>> >> >> Indeed it is simpler, which is a powerful argument for it. You don't even >> have to mention "median." >> >> It *does have a problem*, which may show up in simulations. I'd prefer >> this method if completion in a single round is being insisted on. I'd want >> to see if the previous round winner and the plurality winner in the next >> round agree. If they do, easily, done. If not, then it could be time for a >> runoff. >> >> As stated, the method is not Condorcet compliant. In a runoff system or >> if the completion in the first round requires coincidence of the plurality >> winner at both ranks, I suspect it is Condorcet compliant *as to the >> evaluated ranks.* It's simple to extend that by using pairwise analysis on >> all the ranks. >> >> GMJ still has certain advantages. Because it's cleaner and more >>> symmetrical in an abstract sense, its criterion compliances are slightly >>> better; and uı|ʞɔnq-ᴚƎ does not allow reporting via 1 number per >>> candidate. But these are minor, technical points. While I still have a >>> father's affection for GMJ, I think that uı|ʞɔnq-ᴚƎ is now my >>> favorite system. >>> >> >> It could be quite good. I'd want to see simulation analysis of it by >> comparison with other methods. >> >> >> Obviously the name needs fixing; I've left it with a deliberately >>> unusable one for now. I'd be happy to call it IRAV, or APV, or whatever >>> other people support in this thread. >>> >> >> It's a Bucklin method! It merely deals with the issue of multiple >> majorities. As I've written, we should be so lucky as to have those. What >> this would do is to encourage, relatively, additional approvals at the >> lower rank. It is an additional LnH protection. >> >> Bucklin-ER/MMP? Multiple Majority Protection. >> >> Multiple Majorities occur because the majority is a bit over-eager to >> compromise. This method backs up if a multiple majority occurs. By doing >> so, it makes the so-called "chicken dilemma" less of a dilemma. The chicken >> dilemma is a fear of LnH failure. Do I vote for a compromise or do I >> continue to stand for my Favorite(s)? >> >> To make this more obvious and more *accurate*, consider the use of more >> ranks. With more approved ranks, a multiple majority becomes less likely, >> and a majority is cleanly found, more often. This, then, is a method of >> handling the rarer multiple majorities. >> >> And, did we mention, it is *easy to explain*? >> >> *Somebody* has been listening to my rantings. >> >> Thanks, Jameson. Great work. >> > > > ---- > Election-Methods mailing list - see http://electorama.com/em for list info > >
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