I forgot to mention: Bucklin would be another good possibility for the other finalist-choosing method, for use along with MMPO. Bucklin's strategy has more in common with Approval than with the pairwise-count methods. Michael Ossipoff On Oct 18, 2016 5:11 PM, "Forest Simmons" <fsimmons@pcc.edu> wrote: > The reason I thought of restricting one of the methods to Smith was to > increase the likelihood that at least one of the finalists came from > sincere Smith, i.e. to make it unlikely that the sincere ballots reveal a > CWs which is not one of the finalists, easy to explain to the experts, but > hard to explain to the lay person. > > Do you see a way to do this? > > On Tue, Oct 18, 2016 at 2:40 PM, Michael Ossipoff <email9648742@gmail.com> > wrote: > >> It should be MMPO, rather than Smith//MMPO, for one finalist-choosing >> method, and Approval, Inferred-Approval, or Score for the other, because >> MMPO, Approval, & Score meet FBC. >> >> If Plain MMPO were replaced by anything else, Weak CD would be lost. >> >> If, for the other finalist-choosing method, Approval, Inferred-Approval >> or Score were replaced by MAM or Beatpath, then both finalist-choosing >> methods would share the same strategic vulnerabilities. >> >> Michael Ossipoff >> On Oct 18, 2016 1:42 PM, "Forest Simmons" <fsimmons@pcc.edu> wrote: >> >>> I appreciate all of the great insights from Kristofer, Chris Benham, and >>> Michael Ossipoff. >>> >>> Especially thanks to Kristofer for being a good sport about my >>> forwarding an email with his private earlier input included. It was too >>> late when I realized I hadn't deleted that part. >>> >>> Intuitively, I think Chris is right that Pushover is the biggest >>> potential problem. But I don't see an obvious example. >>> >>> Michael is right that we need to consider other possibilities for the >>> two base methods for picking the finalists. >>> >>> I like MMPO or Smith//MMPO as one of them since MMPO is one method that >>> doesn't just reduce to Approval when all candidates are ranked or rated at >>> the extremes. I think that the other method should be one that does reduce >>> to Approval at the extremes, like River, MAM/RankedPairs, or >>> Beatpath/Tideman/Schulz. It could be a Bucklin variant like MJ, Andy >>> Jennings's Chiastic Approval, or Jameson's MAS. >>> >>> Like Michael I think that Range itself gives too much incentive to vote >>> at the extremes on the strategic ballots. Better to use Approval or an >>> approval variant so that the strategic ratings are not unduly compressed >>> for the other base method. >>> >>> I like Kristofer's insights about the subtle differences between the >>> proposed "manual" version in contradistinction to a DSV version that >>> automates strategy for the two methods based on the first set of (perhaps >>> somewhat pre-strategized) ratings. >>> >>> In particular he pointed out how certain procedural rules can >>> externalize the paradoxes of voting. To a certain extent Approval avoids >>> bad properties by externalizing them. The cost is the "burden" of the >>> voter deciding whom to approve. As Ron LeGrand has so amply demonstrated, >>> any time you try to automate approval strategy in a semi-optimal way, you >>> end up with a non-monotone method. By the same token IRV can be thought of >>> as a rudimentary DSV approach to plurality voting, so it should be no >>> surprise that IRV/STV is non-monotone. >>> >>> A better example, closer to the Kristofer's, idea is Asset Voting. It >>> externalizes everything, which makes it impossible to contradict any nice >>> ballot based property. Because of this there is an extreme resulting >>> strategic burden, but in this case that burden is placed squarely onto the >>> shoulders of the candidates, not the voters. Presumably the candidates are >>> up to that kind of burden since they are, after all, politicians (in our >>> contemplated public applications). >>> >>> But this brings up another intriguing idea. Let one of the two base >>> methods be Asset Voting, so that the sincere ballots decide between (say) >>> the MMPO winner and the Asset Voting winner. >>> >>> Thanks Again, >>> >>> Forest >>> >>> On Tue, Oct 18, 2016 at 12:32 PM, Michael Ossipoff < >>> email9648742@gmail.com> wrote: >>> >>>> If course the balloting for choosing between the 2 finalists need only >>>> be rankings, to show preferences between the 2 finalists, whoever they turn >>>> out to be. >>>> >>>> Some variations occurred to me. I'm not saying that any of them would >>>> be better. I just wanted to mention them, without any implication that they >>>> haven't already occurred to everyone. >>>> >>>> Both of the following possibilities have disadvantages, in comparison >>>> to the initial proposal: >>>> >>>> 1. What if, for the initial 2 counts, it were a Score-count, in >>>> addition to the MMPO count. >>>> >>>> One argument against that variation is that a voter's inferred >>>> approvals are likely to be more optimal for hir than the Score ratings on >>>> which they're based. >>>> >>>> 2. For the 2 initial counts, what if the MMPO count used a separate >>>> ranking, & the Approval count used a separate set of Approval-marks? >>>> >>>> Would that make it easier for Chris's pushover strategist? >>>> >>>> What other positive & negative results? >>>> >>>> One possible disadvantage that occurs to me is that overcompromising >>>> voters might approve lower than than necessary, if the approval were >>>> explicitly voted. ...in comparison to their ratings-which tend to soften >>>> voting errors. >>>> >>>> So far, it appears that the initial proposal is probably the best one. >>>> >>>> Michael Ossipoff >>>> On Oct 17, 2016 1:49 PM, "Forest Simmons" <fsimmons@pcc.edu> wrote: >>>> >>>>> Kristofer, >>>>> >>>>> Perhaps the way out is to invite two ballots from each voter. The >>>>> first set of ballots is used to narrow down to two alternatives. It is >>>>> expected that these ballots will be voted with all possible manipulative >>>>> strategy ... chicken defection, pushover, burial, etc. >>>>> >>>>> The second set is used only to decide between the two alternatives >>>>> served up by the first set. >>>>> >>>>> A voter who doesn't like strategic burden need not contribute to the >>>>> first set, or could submit the same ballot to both sets. >>>>> >>>>> If both ballots were Olympic Score style, with scores ranging from >>>>> blank (=0) to 10, there would be enough resolution for all practical >>>>> purposes. Approval voters could simply specify their approvals with 10 and >>>>> leave the other candidates' scores blank. >>>>> >>>>> There should be no consistency requirement between the two ballots. >>>>> They should be put in separate boxes and counted separately. Only that >>>>> policy can guarantee the sincerity of the ballots in the second set. >>>>> >>>>> In this regard it is important to realize that optimal perfect >>>>> information approval strategy may require you to approve out of order, i.e. >>>>> approve X and not Y even if you sincerely rate Y higher than X. [We're >>>>> talking about optimal in the sense of maximizing your expectation, meaning >>>>> the expectation of your sincere ratings ballot, (your contribution to the >>>>> second set).] >>>>> >>>>> Nobody expects sincerity on the first set of ballots. If some of them >>>>> are sincere, no harm done, as long as the methods for choosing the two >>>>> finalists are reasonable. >>>>> >>>>> On the other hand, no rational voter would vote insincerely on hir >>>>> contribution to the second set. The social scientist has a near perfect >>>>> window into the sincere preferences of the voters. >>>>> >>>>> Suppose the respective finalists are chosen by IRV and Implicit >>>>> Approval, respectively, applied to the first set of ballots. People's eyes >>>>> would be opened when they saw how often the Approval Winner was sincerely >>>>> preferred over the IRV winner. >>>>> >>>>> Currently my first choice of methods for choosing the respective >>>>> finalists would be MMPO for one of them and Approval for the other, with >>>>> the approval cutoff at midrange (so scores of six through ten represent >>>>> approval). >>>>> >>>>> Consider the strategical ballot set profile conforming to >>>>> >>>>> 40 C >>>>> 32 A>B >>>>> 28 B >>>>> >>>>> The MMPO finalist would be A, and the likely Approval finalist would >>>>> be B, unless too many B ratings were below midrange. >>>>> >>>>> If the sincere ballots were >>>>> >>>>> 40 C >>>>> 32 A>B >>>>> 28 B>A >>>>> >>>>> then the runoff winner determined by the second set of ballots would >>>>> be A, the CWs. The chicken defection was to no avail. Note that even >>>>> though this violates Plurality on the first set of ballots, it does not on >>>>> the sincere set. >>>>> >>>>> On the other hand, if the sincere set conformed to >>>>> >>>>> 40 C>B >>>>> 32 A>B >>>>> 28 B>C >>>>> >>>>> then the runoff winner would be B, the CWs, and the C faction attempt >>>>> to win by truncation of B would have no effect. A burial of B by the C >>>>> faction would be no more rewarding than their truncation of B. >>>>> >>>>> So this idea seems to take care of the tension between methods that >>>>> are immune to burial and methods that are immune to chicken defection. >>>>> >>>>> Furthermore, the plurality problem of MMPO evaporates. Even if all of >>>>> the voters vote approval style in either or both sets of ballots, the >>>>> Plurality problem will automatically evaporate; on approval style ballots >>>>> the Approval winner pairwise beats all other candidates, including the MMPO >>>>> candidate (if different from the approval winner). >>>>> >>>>> What do you think? >>>>> >>>>> Forest >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> On Sun, Oct 16, 2016 at 1:30 AM, Kristofer Munsterhjelm < >>>>> km_elmet@t-online.de> wrote: >>>>> >>>>>> On 10/15/2016 11:56 PM, Forest Simmons wrote: >>>>>> > Thanks, Kristofer; it seems to be a folk theorem waiting for >>>>>> formalization. >>>>>> > >>>>>> > That reminds me that someone once pointed out that almost all of the >>>>>> > methods favored by EM list enthusiasts reduce to Approval when only >>>>>> top >>>>>> > and bottom votes are used, in particular when Condorcet methods >>>>>> allow >>>>>> > equal top and multiple truncation votes they fall into this category >>>>>> > because the Approval Winner is the pairwise winner for approval >>>>>> style >>>>>> > ballots. >>>>>> > >>>>>> > Everything else (besides approval strategy) that we do seems to be >>>>>> an >>>>>> > effort to lift the strategical burden from the voter. We would >>>>>> like to >>>>>> > remove that burden in all cases, but at least in the zero info case. >>>>>> > Yet that simple goal is somewhat elusive as well. >>>>>> >>>>>> Suppose we have a proof for such a theorem. Then you could have a >>>>>> gradient argument going like this: >>>>>> >>>>>> - If you're never harmed by ranking Approval style, then you should >>>>>> do so. >>>>>> - But figuring out the correct threshold to use is tough (strategic >>>>>> burden) >>>>>> - So you may err, which leads to a problem. And even if you don't, if >>>>>> the voters feel they have to burden their minds, that's a bad thing. >>>>>> >>>>>> Here, traditional game theory would probably pick some kind of mixed >>>>>> strategy, where you "exaggerate" (Approval-ize) only to the extent >>>>>> that >>>>>> you benefit even when taking your errors into account. But such an >>>>>> equilibrium is unrealistic (we'd have to find out why, but probably >>>>>> because it would in the worst case require everybody to know about >>>>>> everybody else's level of bounded rationality). >>>>>> >>>>>> And if the erring causes sufficiently bad results, we're left with two >>>>>> possibilities: >>>>>> >>>>>> - Either suppose that the method is sufficiently robust that most >>>>>> voters >>>>>> won't use Approval strategy (e.g. the pro-MJ argument that Approval >>>>>> strategy only is a benefit if enough people use it, so most people >>>>>> won't, so we'll have a correlated equilibrium of sorts) >>>>>> >>>>>> - That any admissible method must have a "bump in the road" on the way >>>>>> from a honest vote to an Approval vote, where moving closer to >>>>>> Approval-style harms the voter. Then a game-theoretical voter only >>>>>> votes >>>>>> Approval style if he can coordinate with enough other voters to pass >>>>>> the >>>>>> bump, which again is unrealistic. >>>>>> >>>>>> But solution #2 will probably destroy quite a few nice properties >>>>>> (like >>>>>> monotonicity + FBC; if the proof is by contradiction, then we'd know >>>>>> some property combinations we'd have to violate). So we can't have it >>>>>> all. >>>>>> >>>>> >>>>> >>> >