<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px"><div id="yui_3_16_0_ym19_1_1473724831853_28901">Hi Jameson,</div><div id="yui_3_16_0_ym19_1_1473724831853_28901"><br></div><div id="yui_3_16_0_ym19_1_1473724831853_28901">"Downvoted by most" means the candidate with the single greatest number of downvotes? This could be the (voted, unique) majority favorite couldn't it?</div><div id="yui_3_16_0_ym19_1_1473724831853_28901"><br></div><div id="yui_3_16_0_ym19_1_1473724831853_28901" dir="ltr">How does this violate "irrelevant ballots"? I must be misunderstanding it. Does "max amount of upvotes" mean 100% of the voters, or just the greatest number of upvotes that occurs?</div><div id="yui_3_16_0_ym19_1_1473724831853_28901"><br></div><div id="yui_3_16_0_ym19_1_1473724831853_28901">I do like antiplurality mechanisms.</div><div id="yui_3_16_0_ym19_1_1473724831853_28901"><br></div><div id="yui_3_16_0_ym19_1_1473724831853_28901">Kevin</div><div class="qtdSeparateBR" id="yui_3_16_0_ym19_1_1473724831853_28906"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym19_1_1473724831853_28910" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px;" id="yui_3_16_0_ym19_1_1473724831853_28909"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_ym19_1_1473724831853_28908"> <div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_28907"> <font size="2" face="Arial" id="yui_3_16_0_ym19_1_1473724831853_28911"> <hr size="1"> <b><span style="font-weight:bold;">De :</span></b> Jameson Quinn <jameson.quinn@gmail.com><br> <b><span style="font-weight: bold;">À :</span></b> Kevin Venzke <stepjak@yahoo.fr>; electionsciencefoundation <electionscience@googlegroups.com> <br><b><span style="font-weight: bold;">Cc :</span></b> EM <election-methods@lists.electorama.com><br> <b><span style="font-weight: bold;">Envoyé le :</span></b> Lundi 12 septembre 2016 20h37<br> <b><span style="font-weight: bold;">Objet :</span></b> Re: [EM] Fwd: Fwd: U/P voting: new name for simple 3-level method.<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_ym19_1_1473724831853_28912"><br><div id="yiv5839231470"><div id="yui_3_16_0_ym19_1_1473724831853_29369"><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29368">Here's a new proposed variant of U/P with a simple default:<div><br clear="none"></div><div>Voters may rate each candidate as "unacceptable" (downvote), "preferred" (upvote), or "acceptable" (neither). Default is neither.</div><div><br clear="none"></div><div id="yui_3_16_0_ym19_1_1473724831853_30547">Any candidate downvoted by most, or with fewer than half the max amount of upvotes, is disqualified, unless that would disqualify everyone. The winner is the remaining candidate with the most upvotes.</div><div><br clear="none"></div><div id="yui_3_16_0_ym19_1_1473724831853_29367">The "fewer than half the max" rule prevents dark-horse winners, without resorting to strange defaults. It has no effect on a two-way chicken dilemma. Though in theory it could affect an evenly-balanced three-way chicken dilemma (in a four-way race), I think there's a negligible chance that such a scenario would be so balanced.</div><div id="yui_3_16_0_ym19_1_1473724831853_29371"><br clear="none"></div><div id="yui_3_16_0_ym19_1_1473724831853_29440">I know that Chris doesn't like this method's violation of "irrelevant ballots". Myself, I think that no voters are irrelevant; even if they don't express an opinion between the two frontrunners, they may have one. (True, they may not; but that's not the first assumption I'd make.)</div></div><div class="yiv5839231470gmail_extra" id="yui_3_16_0_ym19_1_1473724831853_29373"><br clear="none"><div class="yiv5839231470gmail_quote" id="yui_3_16_0_ym19_1_1473724831853_29381">2016-09-12 20:22 GMT-04:00 Kevin Venzke <span dir="ltr"><<a rel="nofollow" shape="rect" ymailto="mailto:stepjak@yahoo.fr" target="_blank" href="mailto:stepjak@yahoo.fr">stepjak@yahoo.fr</a>></span>:<br clear="none"><div class="yiv5839231470yqt7839525709" id="yiv5839231470yqt20993"><blockquote class="yiv5839231470gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;" id="yui_3_16_0_ym19_1_1473724831853_29380"><div id="yui_3_16_0_ym19_1_1473724831853_29379"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;" id="yui_3_16_0_ym19_1_1473724831853_29378"><div id="yui_3_16_0_ym19_1_1473724831853_29377"><div id="yui_3_16_0_ym19_1_1473724831853_29376"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;" id="yui_3_16_0_ym19_1_1473724831853_29375"><div id="yui_3_16_0_ym19_1_1473724831853_29439"><span>Hi Jameson,</span></div><div id="yui_3_16_0_ym19_1_1473724831853_29374"><span><br clear="none"></span></div><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_30549"><span id="yui_3_16_0_ym19_1_1473724831853_30548">I think it is a positive thing that the MTA B/C majority coalition can give their sincere preferences (!), while using the strategy they're expected to use (i.e. middle slot as tiebreaker given multiple majorities), without risk of this strategy backfiring. (Voters can accidentally elect the less preferred of B or C, but that is the inescapable chicken dilemma, I would say.)</span></div><div dir="ltr"><span><br clear="none"></span></div><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29435"><span id="yui_3_16_0_ym19_1_1473724831853_29434">I have some sympathy for your claim that C should not be able to win with few top ratings. But that sympathy is not tied to Borda counts, it is based on wanting to reduce the truncation incentive for the B voters. This, U/P does not really do, because the B>C voters would be taking a large risk that they are helping to put C (alone) over the threshold of majority approval.</span></div><div dir="ltr"><span><br clear="none"></span></div><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29382"><span id="yui_3_16_0_ym19_1_1473724831853_29411">So I don't think either of these ballot sets is likely under U/P, and it sounds like you agree with that and think it is good (because it deters a pathological ballot set)? Do you have a stance (or at least, see use in determining a stance) on how U/P voters in these scenarios should be voting?</span></div><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29412"><span><br clear="none"></span></div><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29410"><span>Kevin</span></div><div id="yui_3_16_0_ym19_1_1473724831853_29383"><br clear="none"><br clear="none"></div></div></div></div><div id="yui_3_16_0_ym19_1_1473724831853_29389"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;" id="yui_3_16_0_ym19_1_1473724831853_29388"> <div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;" id="yui_3_16_0_ym19_1_1473724831853_29387"> <div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29409"><span class="yiv5839231470"> <font size="2" face="Arial"> </font></span><hr size="1"> <b><span style="font-weight:bold;">De :</span></b> Jameson Quinn <<a rel="nofollow" shape="rect" ymailto="mailto:jameson.quinn@gmail.com" target="_blank" href="mailto:jameson.quinn@gmail.com">jameson.quinn@gmail.com</a>><br clear="none"> <b><span style="font-weight:bold;">À :</span></b> EM <<a rel="nofollow" shape="rect" ymailto="mailto:election-methods@lists.electorama.com" target="_blank" href="mailto:election-methods@lists.electorama.com">election-methods@lists. electorama.com</a>> <br clear="none"> <b><span style="font-weight:bold;">Envoyé le :</span></b> Dimanche 11 septembre 2016 1h51<br clear="none"> <b><span style="font-weight:bold;">Objet :</span></b> [EM] Fwd: Fwd: U/P voting: new name for simple 3-level method.<br clear="none"> </div> <div id="yui_3_16_0_ym19_1_1473724831853_29386"><div id="yui_3_16_0_ym19_1_1473724831853_29385"><div class="yiv5839231470h5" id="yui_3_16_0_ym19_1_1473724831853_29384"><br clear="none"><div id="yui_3_16_0_ym19_1_1473724831853_29408"><br clear="none"><br clear="none"></div><div id="yui_3_16_0_ym19_1_1473724831853_29399"><div id="yui_3_16_0_ym19_1_1473724831853_29398"><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29397"><div id="yui_3_16_0_ym19_1_1473724831853_29396"><div dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29395"><div id="yui_3_16_0_ym19_1_1473724831853_29394"><div id="yui_3_16_0_ym19_1_1473724831853_29393"><span id="yui_3_16_0_ym19_1_1473724831853_29407">2016-09-10 21:26 GMT-04:00 C.Benham <span dir="ltr" id="yui_3_16_0_ym19_1_1473724831853_29406"><<a rel="nofollow" shape="rect" ymailto="mailto:cbenham@adam.com.au" target="_blank" href="mailto:cbenham@adam.com.au" id="yui_3_16_0_ym19_1_1473724831853_29405">cbenham@adam.com.au</a>></span>:<br clear="none"></span><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;" id="yui_3_16_0_ym19_1_1473724831853_29392"><span>On 9/11/2016 5:02 AM, Kevin Venzke wrote:<br clear="none">
<br clear="none">
</span><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;" id="yui_3_16_0_ym19_1_1473724831853_29401">
43: A<br clear="none">
24: B>C<br clear="none">
23: C>B<br clear="none">
10: D<br clear="none">
<br clear="none">
Under MTA the B and C voters are being completely reasonable: They hope for majority approval but can still hope for a win if they<br clear="none">
don't get it.<br clear="none">
<br clear="none">
Strategy is less likely to produce these ballots under U/P because the B and C voters are taking a gamble. To get a similar outcome<br clear="none">
they have to vote B=C. Anyone who doesn't is functionally defecting!<br clear="none">
</blockquote>
<br clear="none">
C: A very good example! Assuming MTA and MCA use Top Ratings scores to break Approval ties, they both elect the Condorcet winner B.<br clear="none"></blockquote><div><br clear="none"></div><div id="yui_3_16_0_ym19_1_1473724831853_29420">But both could be shifted to C with a single C-only ballot, even if the B:C ratio were 46:1 instead of 24:23.</div><span></span><div id="yui_3_16_0_ym19_1_1473724831853_29422"> </div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;" id="yui_3_16_0_ym19_1_1473724831853_29421">
<br clear="none">
U/P's under-use of the middle ratings slot means that it relies more on its "majority disqualification" mechanism which seems to make it more<br clear="none">
vulnerable to irrelevant ballots, as in the example.<br clear="none">
<br clear="none">
Under U/P, without the irrelevant D ballots, A and D are disqualified and B is the glorious winner. With them, B and C and D are disqualified and (without needing<br clear="none">
any others to be disqualified) A wins.<br clear="none">
<br clear="none">
This causes me to reject U/P as clearly worse than MTA and MCA. Of the three I (again) rate MTA as the least bad.<br clear="none"></blockquote><div><br clear="none"></div><div>I think MTA is pretty darn good. I still prefer U/P.</div><div><br clear="none"></div><div>I think that scenarios like the above are fundamentally pathological; any possible winner has only minority approval, so that even assuming all ballots are semi-honest, any of them could be a true Condorcet loser. Thus, I believe that it's more important for a system to try to avoid scenarios like the above, than to try to find a perfect winner in such a scenario. In fact, in the related scenario:</div><div><br clear="none"></div><div><br clear="none">43: A<br clear="none">40: B>C</div><div id="yui_3_16_0_ym19_1_1473724831853_29427">6: C>B<br clear="none">1: C<br clear="none">10: D<br clear="none"></div><div><br clear="none"></div><div>... I think that a case can be made for either A or B. After all, they'd be tied if we try to approximate Score by using truncatable Borda here. But no serious case can be made for C or D, even though C wins MTA and MCA.</div><div><br clear="none"></div><div id="yui_3_16_0_ym19_1_1473724831853_29425">Anyway, I think U/P does a better job trying to discourage the kind of strategy that would lead to a scenario like the above. And part of that is the default rule which Chris has criticized.</div><div><br clear="none"></div><div>One possible alternative default rule: ballots alternate between defaulting to "acceptable" and to "unacceptable". Each ballot clearly states which default it uses, and there is a place on the ballot to globally change that default. (I doubt Chris will like this idea, but it is at least straightforward, explicit, and easy to describe.)</div><div id="yui_3_16_0_ym19_1_1473724831853_29430"><br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex;">
<br clear="none">
Chris Benham<br clear="none">
<br clear="none">
<br clear="none">
</blockquote></div><br clear="none"></div></div>
</div><br clear="none"></div></div></div><br clear="none"></div></div><span class="yiv5839231470">----<br clear="none">Election-Methods mailing list - see <a rel="nofollow" shape="rect" target="_blank" href="http://electorama.com/em">http://electorama.com/em </a>for list info<br clear="none"><br clear="none"><br clear="none"></span></div> </div> </div> </div></div></div></blockquote></div></div><br clear="none"></div></div></div><br><div class="yqt7839525709" id="yqt09937">----<br clear="none">Election-Methods mailing list - see <a shape="rect" href="http://electorama.com/em" target="_blank">http://electorama.com/em </a>for list info<br clear="none"></div><br><br></div> </div> </div> </div></div></body></html>