[EM] The Green scenario, and IRV in the Green scenario, is a new topic here. Hence these additional comments. Clarification of position and why.

[Juho Laatu]

On 4.2.2013, at 15.40, Peter Zbornik wrote:

> Being a green party member (although a Czech one and not US), I would
> advocate only the top-two-run-off
> variant of IRV, i.e. elimination of the candidates and transfer of
> votes until two remain, no quota for election (or quota=100%) except
> for the case where one candidate has more than 50% of first
> preferences.
> 
> The top two candidates would meet in a second round in IRV.
> A candidate would be elected if he/she would get more than 50% of the votes.
> 
> Empty votes would count as  valid votes in both first and second round.
> 
> If no candidate would be elected in second round new elections would take place.
> 
> The advantages of the proposed election system are
> 1) the voters are given a chance to concentrate only on two candidates
> in the second round, and are thus allowed to change their preferences.
> 2) blank votes together with IRV might make the candidates less
> polarized, as, given a large number of blank votes, the candidate with
> the highest number of votes in the second round would have to rely on
> the second preferences of the voters for the opposing candidate in
> order to get 50%+ votes.
> 
> PZ

If one wants to guarentee sufficient support of the winner (50% in the description above), then one nice approach is to have an explicit approval cutoff in the ballots. By comparing each candidate to that cutoff one can count how wide support each candidate has. You can use that information also to determine if someone should win already based on the first round, or which candidates shoud go to the later rounds.

For example, if the winner of the first round (maybe using a Condorcet method) has >50% approval, elect him. Otherwise arrange a second round with the same rules, except that you may drop some of the candidates out (maybe all but two).

My point is just that this aproach is formally nice and it collects useful additional information that can be used in many ways, like making the decision already after the first round.

Juho