[EM] Cooperative voting

[Kevin Venzke]

Hi Andy,
If I take this example, looking at only 51 out of 100 voters (imagine the other 49 vote for other candidates entirely):10 A>B41 B>A
Under the original rule, all A voters will approve B, and 10 B voters will approve A. B probably wins. That seems fair. The B voters get an advantage from having more plurality votes.
Under alternative 1, the smaller fraction is 100%. That would cause the two candidates to be tied at 51. (Or nearly tied, with a stray approval somewhere making the difference.) I think alternative 2 also gives this outcome. This seems a lot worse to me, because there's not really a sense that approvals constitute "lower" preferences.
>From the perspective of a sincere voter, the "approval" option signifies conditioning their opinion of a candidate on how that candidate's supporters vote. It's not such a crazy idea if one doesn't know much about a given candidate. I wonder if more can be done with the concept.
My main concern with this type of method is the situation that a bloc of voters (supporting candidate A let's say) "defects" because they don't actually like candidate B. Even if B supporters know this is the situation, and even if B supporters would be willing to support A anyway, they don't have a (sincere) way of doing this.
Kevin

      De : Andy Jennings <elections at jenningsstory.com>
 À : Election Methods <election-methods at electorama.com> 
 Envoyé le : Vendredi 16 octobre 2015 13h28
 Objet : [EM] Cooperative voting
   
Cooperative voting
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Voters indicate one favorite candidate and separately indicate all other candidates they approve of.

Approvals are an agreement to "conditionally cooperate".  If A is my favorite but I also approved B, the approval for B will not count unless there is a corresponding B-voter who approved A.

Counting
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1. Candidates start with their plurality totals.

2. Each pair of candidates (A,B) is examined.  Take the smaller of the number of A-voters who approved B and the number of B-voters who approved A and add it to both A's and B's totals.

Motivation
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Having run the straw poll for the Repulican Liberty Caucus last weekend, I've been thinking about approval voting, the chicken (Burr) dilemma, and the prisoners' dilemma.

One solution to a prisoners' dilemma situation is to offer "conditional cooperation".

Alternatives
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1) Use percentages instead.  In step 2, let p equal the smaller of the fraction of A-voters who approved B and the fraction of B-voters who approved A.  p times the number of A-voters is added to B's total.  p times the number of B-voters is added to A's total.

2) Use non-approval instead.  In step 2, let x equal the larger of the number of A-voters who did NOT approve B and the number of B-voters who did NOT approve A.  The number of A-voters minus x (if positive) is added to B's total.  The number of B-voters minus x (if positive) is added to A's total.

Questions
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Has this system been proposed before by another name?

How can it be abused?

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