<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><DIV>Forest,<BR>"What nicer distribution can you think of.."</DIV>
<DIV> </DIV>
<DIV>"Nice" (and "nicer") is a fuzzy emotional/aesthetic term that I might apply to food, music, people etc.</DIV>
<DIV>but seems unscientific and out-of-place here (and I'm not sure exactly what it's supposed to mean). </DIV>
<DIV> </DIV>
<DIV>I can see that such a distribution is more comfortable for methods that try to elect the centrist candidate.</DIV>
<DIV> </DIV>
<DIV>I see IRV as FPP that trades most of its monotonicity criteria (including mono-raise and Participation but </DIV>
<DIV>not mono-add-top, mono-add-plump or mono-append) to gain Clone-Winner and Majority for Solid</DIV>
<DIV>Coalitions (and Mutual Dominat Third and Condorcet Loser).</DIV>
<DIV> </DIV>
<DIV>It keeps FPP's compliances with Woodall's Plurality criterion, Later-no-Harm, Later-no-Help and Clone-Loser.</DIV>
<DIV> </DIV>
<DIV>The "representativeness criteria" it meets generally allow for a bigger set of allowable winners than say<BR>the Smith set, and its monotonity failures mean that it chooses a winner from this set a bit erratically.</DIV>
<DIV>But I think your use of the term "pathology" (comparing it to a disease and so something that is self-evidently</DIV>
<DIV>unacceptable) is biased and out of place.</DIV>
<DIV> </DIV>
<DIV>I also think that the argument that IRV makes a good stepping-stone to PR is strong. Truly proportional </DIV>
<DIV>multi-winner methods meet Droop Proportionality for Solid Coalitions (equivalent in the single-winner </DIV>
<DIV>case to Majority for Solid Coalitions, aka Mutual Majority.)<BR></DIV>
<DIV>Single-winner STV's virtues of Later-no-Harm and Clone Independence survive into the multi-winner </DIV>
<DIV>version (which of course meets Droop Proportionality SC), while for multi-winner methods the Condorcet </DIV>
<DIV>criterion and Favourite Betrayal are both incompatible with Droop PSC. Also I think Later-no-Harm </DIV>
<DIV>compliance is more valuable for multi-winner methods than for single-winner methods.</DIV>
<DIV><BR>Chris Benham</DIV>
<DIV> </DIV>
<DIV><BR></DIV>
<DIV><BR>Forest Simmons wrote (Sat. Nov.29):</DIV>
<DIV> </DIV>
<DIV>><I> From: Chris Benham <BR>> > Forest,</I></DIV>
<DIV><I>> Given IRV's compliance with the "representativeness criteria" </I><I>Mutual Dominant Third, Majority for<BR>> Solid Coalitions, Condorcet Loser and? Plurality; why should the bad look of its "erratic behaviour"<BR>> be sufficient to condemn IRV in spite of these and other positive criterion compliances such as</I></DIV>
<DIV><I>> Later-no-Harm and Burial Invulnerability?</I></DIV>
<DIV><I></I> </DIV>
<DIV><I>A picture is worth a thousand words. It shows the actual behavior, including the extent of the pathology.<BR></I></DIV>
<DIV><I>> > "....in the best of all possible worlds, namely normally distributed voting populations in no more </I></DIV>
<DIV><I>> than two dimensional issue space."</I></DIV>
<DIV><I>> >CB: Why does that situation you refer to qualify as "the best of all possible worlds" ?</I></DIV><I>
<DIV><BR>> Three points determine a plane, so we cannot expect a lower dimension than two. What nicer </DIV>
<DIV>>distribution can you think of. than normal? But any distribution whose density only depends on distance </DIV>
<DIV>>from the center of the distribution would give exactly the same results for any Condorcet method, without </DIV>
<DIV>>making the IRV results any nicer. </DIV>
<DIV> </DIV>
<DIV>Forest</DIV>
<DIV> </DIV>
<DIV></I><BR> </DIV></div><br>
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