Re: [EM] "FBC vs Condorcet's Criterion"
On 05/08/2012 08:46 PM, Michael Ossipoff wrote: > Since Richard wants to make a "which one wins" comparison between FBC > and Condorcet's Criterion (CC), then I'll remind him that, when FBC > failure sufficiently makes its problem, CC compiance becomes quite > meaningless and valueless. And there is good reason to believe, as > described in my previous post, that Condorcet's FBC failure _will_ > fully make its problem in our public elections. Kristofer: You wrote: I'll get to your larger post later, but it seems what need isn't FBC as such, but rather u/a FBC. [endquote] You're referring to a requirement that FBC not be violated in a u/a election. But does the requirement only apply if _everyone_ regards it as u/a? And of course they can't all agree on what's acceptable and unacceptable, or nothing unacceptable could win, and that would Prevent it from being a u/a election--an election in which there are unacceptable candidates who might win. One could consider writing it so that it applies only if the criterion failure-example writer considers it a u/a election. I'm interested in alternative versions, strengthenings and weakenings, of FBC. That's why I posted a definition for Strong FBC. I posted one for Intermediate FBC too, but, later, it seemed to me, and still does, that "Intermediate FBC" would be better named "Specific Simple Compromise Strategy" (SSCS). I don't suppose that it would be of interest to any of us. It was an effort to say something about exactly what it would take to make Compromise beat Worse. ...after you'd commented on that matter. Approval, and almost surely ABucklin, in all of its versions, meets SSCS. I don't know if pairwise-count methods can meet it. Anyway, because I consider all of our public elections to be u/a, then an FBC that only applies in u/a elections is of interest. Maybe such a weakening of FBC could be acceptable, while still compatible with criteria important to some voting system reform advocates.. I don't know, because of course the idea of a u/a FBC is completely new to me. But it's definitely of interest if there could be a good enough FBC version that wouldn't be incompatible with criteria important to some voting system reform advocates. If enough people, all of the ones who agree with me about something important, don't agree on what's acceptable and what isn't, that can be a problem. There was once a book entitled _I've Been Down So Long, It Looks Like Up To Me_. Many voters, probably a very large proportion of them, are like that, in their judgment of what is acceptable. I don't know how such disagreements would affect the possibility of a u/a FBC. Mike Ossipoff Here's a Condorcet method I think meets u/a FBC: Each voter submits a ranked ballot with an Approval cutoff. The most Approved candidate in the Smith set wins. If everybody ranks Approval style, then this becomes Approval. So let's see if there's any reason to favorite betray instead of ranking Approval style. If there is no cycle, then you can't make an acceptable have a greater chance of winning over an unacceptable by ranking Compromise over Favorite versus ranking Favorite over Compromise. If there's a cycle and Favorite is in the Smith set, but Compromise is not, then the only reason for getting Compromise into the Smith set would be to defend against an unacceptable candidate winning. However, you can do that by just voting Approval style. Since Smith set members are "only beaten by other Smith set members", Favorite vs Compromise doesn't enter into it as long as you put both above the cutoff and all the unacceptables below it. If there's a cycle and Compromise is in the Smith set, but Favorite is not, then because this is an u/a election, it doesn't matter. You'll still get an acceptable. If there's a cycle and neither Compromise nor Favorite is in the Smith set, then voting Approval style will make Compromise and Favorite both maximally work to push the unacceptables out of the Smith set. Hence it seems that the method above meets u/a FBC. By the time people get past u/a, they'll no longer be overcompromising and so "proper" FBC failure doesn't matter. So Condorcet can meet u/a FBC. I'm not saying Smith,Approval is necessarily a good method, but I only have to show a single method to disprove that u/a FBC and Condorcet is incompatible. Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] "FBC vs Condorcet's Criterion"
Hi Kristofer, De : Kristofer Munsterhjelm >À : Michael Ossipoff >Cc : election-meth...@electorama.com >Envoyé le : Mercredi 9 mai 2012 9h54 >Objet : Re: [EM] "FBC vs Condorcet's Criterion" > > >On 05/08/2012 08:46 PM, Michael Ossipoff wrote: >> Since Richard wants to make a "which one wins" comparison between >> FBC and Condorcet's Criterion (CC), then I'll remind him that, when >> FBC failure sufficiently makes its problem, CC compiance becomes >> quite meaningless and valueless. And there is good reason to believe, >> as described in my previous post, that Condorcet's FBC failure _will_ >> fully make its problem in our public elections. > >I'll get to your larger post later, but it seems what need isn't FBC as such, >but rather u/a FBC. > >Here's a Condorcet method I think meets u/a FBC: Each voter submits a ranked >ballot with an Approval cutoff. The most Approved candidate in the Smith set >wins. > >If everybody ranks Approval style, then this becomes Approval. So let's see if >there's any reason to favorite betray instead of ranking Approval style. > >If there is no cycle, then you can't make an acceptable have a greater chance >of winning over an unacceptable by ranking Compromise over Favorite versus >ranking Favorite over Compromise. > >If there's a cycle and Favorite is in the Smith set, but Compromise is not, >then the only reason for getting Compromise into the Smith set would be to >defend against an unacceptable candidate winning. However, you can do that by >just voting Approval style. Since Smith set members are "only beaten by other >Smith set members", Favorite vs Compromise doesn't enter into it as long as >you put both above the cutoff and all the unacceptables below it. > >If there's a cycle and Compromise is in the Smith set, but Favorite is not, >then because this is an u/a election, it doesn't matter. You'll still get an >acceptable. > >If there's a cycle and neither Compromise nor Favorite is in the Smith set, >then voting Approval style will make Compromise and Favorite both maximally >work to push the unacceptables out of the Smith set. > >Hence it seems that the method above meets u/a FBC. By the time people get >past u/a, they'll no longer be overcompromising and so "proper" FBC failure >doesn't matter. So Condorcet can meet u/a FBC. > >I'm not saying Smith,Approval is necessarily a good method, but I only have to >show a single method to disprove that u/a FBC and Condorcet is incompatible. > Did you cover the scenario where both Favorite and Compromise are in the Smith set? If not, is there some reason for u/a FBC (whose definition I don't actually know) why this scenario doesn't matter? In general the way C//A methods fail FBC is by creating incentive to make Compromise beat Favorite because "Worst" will win the approval tiebreaker. Thanks. Kevin Election-Methods mailing list - see http://electorama.com/em for list info
Re: [EM] "FBC vs Condorcet's Criterion"
On 05/08/2012 08:46 PM, Michael Ossipoff wrote: Since Richard wants to make a "which one wins" comparison between FBC and Condorcet's Criterion (CC), then I'll remind him that, when FBC failure sufficiently makes its problem, CC compiance becomes quite meaningless and valueless. And there is good reason to believe, as described in my previous post, that Condorcet's FBC failure _will_ fully make its problem in our public elections. I'll get to your larger post later, but it seems what need isn't FBC as such, but rather u/a FBC. Here's a Condorcet method I think meets u/a FBC: Each voter submits a ranked ballot with an Approval cutoff. The most Approved candidate in the Smith set wins. If everybody ranks Approval style, then this becomes Approval. So let's see if there's any reason to favorite betray instead of ranking Approval style. If there is no cycle, then you can't make an acceptable have a greater chance of winning over an unacceptable by ranking Compromise over Favorite versus ranking Favorite over Compromise. If there's a cycle and Favorite is in the Smith set, but Compromise is not, then the only reason for getting Compromise into the Smith set would be to defend against an unacceptable candidate winning. However, you can do that by just voting Approval style. Since Smith set members are "only beaten by other Smith set members", Favorite vs Compromise doesn't enter into it as long as you put both above the cutoff and all the unacceptables below it. If there's a cycle and Compromise is in the Smith set, but Favorite is not, then because this is an u/a election, it doesn't matter. You'll still get an acceptable. If there's a cycle and neither Compromise nor Favorite is in the Smith set, then voting Approval style will make Compromise and Favorite both maximally work to push the unacceptables out of the Smith set. Hence it seems that the method above meets u/a FBC. By the time people get past u/a, they'll no longer be overcompromising and so "proper" FBC failure doesn't matter. So Condorcet can meet u/a FBC. I'm not saying Smith,Approval is necessarily a good method, but I only have to show a single method to disprove that u/a FBC and Condorcet is incompatible. Election-Methods mailing list - see http://electorama.com/em for list info