[EM] [ApprovalVoting] Re: The IRV-Disease has reached my town.

Tue Mar 5 05:59:14 PST 2019

Juho,

>> 46 A
>> 44 B>C
>> 10 C
>>
>> A>B 46-44 (margin=2)ï¿½ï¿½ï¿½ï¿½ B>C 44-10 (margin=34)ï¿½ï¿½ C>A 54-46 (margin=8)
>>
>> Now Margins elects B,ï¿½ rewarding the outrageous Burial strategy.
>>
>> I can't tolerate any method that elects B in this scenario. Even 
>> assuming that all the votes are sincere,
>> B is clearly the weakest candidate (the least "approved" and 
>> positionally dominated and pairwise-beaten
>> by A.)
>>
> Also here you assume that there is an implicit approval cutoff after 
> the ranked candidates. What if the votes are sincere and there is no 
> implicit approval cutoff?
>
No, I'm only "assuming" that positional information is more meaningful 
than which candidate is "closer" to being the Condorcet winner
according to Margins or which candidate needs the fewest additional 
bullet-votes to become the CW.

Given that Margins is very vulnerable to Burial strategy the argument 
that it's worth putting up with that because with sincere votes B
in this scenario is the best (or a good or even acceptable) candidate is 
.. what??

Or to put it another way, assuming the votes are sincere, you arguments 
against electing A or C are what?

> One might face problems sooner with sincere voting than with strategic 
> voting.
>
> First preferences could be as follows.
>
> 30: far-left
> 21: left
> 19: right
> 30: far-right
>
> If we assume that left hates right, and right hates left, the natural 
> approval limit would be between the left wing and right wing parties. 
> We would get mostly votes that rank only left wing or only right wing 
> candidates. And the winner would be with good probability the far-left 
> candidate, not the expected Condorcet winner (left).

That doesn't bother me much because (a) far-left may be higher "Social 
Utility" than left and (b) probably enough right voters would
be aware that the result is unlikely to be decided by Approval and so 
they would not be taking a huge risk by sincerely ranking left
over far-left.

But having said that, Smith//Approval using ballots thatï¿½ allow voters 
to rank among candidates they don't approve would not be
in my book too bad (and much better than Margins).

> P.S. I think the STV-BTR method that Robert proposed could make a lot 
> of sense in societies where IRV way of thinking is strong.
That method doesn't have good criterion compliances. It's just a gimmick 
to smuggle Condorcet compliance past IRV enthusiasts.
The alternative of just checking for a CW (among remaining candidates) 
before each elimination is much better.

> P.P.S. Limiting the number of ranking levels or number of ranked 
> candidates could make sense when the number of candidates is very 
> high, or just to keep things simple for the vote counting process, or 
> to keep things simple enough for the voters (not to frighten them with 
> the idea of ranking all 100 candidates). I.e. not theoretically ideal, 
> but in practical situations ranking some candidates may be much better 
> than ranking only one, or not bothering to vote at all.

Limiting the number of candidates the voter is allowed to rank makes no 
sense. What has happened to your concern
about "removing information" on who the sincere/ "expected" CW is?

There would be nothing "frightening" about ranking all the candidates if 
doing so is purely optional. But voters who wish
to vote a full ranking should be allowed to.

Chrisï¿½ Benham

On 5/03/2019 6:42 pm, Juho Laatu wrote:
>> On 05 Mar 2019, at 07:45, Chris Benham cbenhamau at yahoo.com.au 
>> <mailto:cbenhamau at yahoo.com.au> [ApprovalVoting] 
>> <ApprovalVoting at yahoogroups.com 
>> <mailto:ApprovalVoting at yahoogroups.com>> wrote:
>
>> Robert,
>>
>
>>
>>> in a ranked ballot, what defines an "approved" candidate?ï¿½ all 
>>> unranked candidates are tied for last place on a ballot.ï¿½ is any 
>>> candidate that is ranked at all "approved"?
>> Yes.
>>
>>> that would change and complicate the meaning of the ranked ballot.
>>
>> Arguably "change" somewhat but I don't see how (overly) "complicate". 
>> Allowing voters to rank among unapproved
>> candidates makes the method more vulnerable to strategy and a lot 
>> more complicated.
>>
> One might face problems sooner with sincere voting than with strategic 
> voting.
>
> First preferences could be as follows.
>
> 30: far-left
> 21: left
> 19: right
> 30: far-right
>
> If we assume that left hates right, and right hates left, the natural 
> approval limit would be between the left wing and right wing parties. 
> We would get mostly votes that rank only left wing or only right wing 
> candidates. And the winner would be with good probability the far-left 
> candidate, not the expected Condorcet winner (left).
>
> The problem with "implicit approval cutoff after the ranked 
> candidates" is that voters would be encouraged not to rank all the 
> major candidates. Not good for Condorcet. That would remove some 
> important information. In this example the sincere Condorcet winner 
> could not be identified anymore.
>
>> 46 A
>> 44 B>C
>> 10 C
>>
>> A>B 46-44 (margin=2)ï¿½ï¿½ï¿½ï¿½ B>C 44-10 (margin=34)ï¿½ï¿½ C>A 54-46 (margin=8)
>>
>> Now Margins elects B,ï¿½ rewarding the outrageous Burial strategy.
>>
>> I can't tolerate any method that elects B in this scenario. Even 
>> assuming that all the votes are sincere,
>> B is clearly the weakest candidate (the least "approved" and 
>> positionally dominated and pairwise-beaten
>> by A.)
>>
> Also here you assume that there is an implicit approval cutoff after 
> the ranked candidates. What if the votes are sincere and there is no 
> implicit approval cutoff?
>
> Juho
>
>
> P.S. I think the STV-BTR method that Robert proposed could make a lot 
> of sense in societies where IRV way of thinking is strong.
>
> P.P.S. Limiting the number of ranking levels or number of ranked 
> candidates could make sense when the number of candidates is very 
> high, or just to keep things simple for the vote counting process, or 
> to keep things simple enough for the voters (not to frighten them with 
> the idea of ranking all 100 candidates). I.e. not theoretically ideal, 
> but in practical situations ranking some candidates may be much better 
> than ranking only one, or not bothering to vote at all.
>
> ----
> Election-Methods mailing list - see https://electorama.com/em for list info

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