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

[Peter Zbornik]

Hi I am afraid a proportional approach in the first round wouldnt
work, it opens up for strategic voting.
Say we have an election with A, B, C.
45 A
30 B A
25 C B A

The first round in a 2-seat election the quota is 34 votes
If we would have a two-round proportional election, then B would win
in the second round.

So A's voters find this out and decide to change their preferences and
10 of the voters of A vote for C
So we have

35 A
30 BA
25 CBA
10 CA

C and A meet in the second round, where A wins.

PZ

2013/2/4 Kristofer Munsterhjelm <km_elmet at lavabit.com>:
> On 02/04/2013 02:40 PM, 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.
>
>
> Perhaps this method would work for runoffs if you can get a more
> sophisticated base method through, say for internal elections:
>
> - Run a single-winner election using your method of choice. Call the winner
> w_1.
> - Use a proportional ranking method to determine the second runoff candidate
> w_2 so that the virtual council {w_1, w_2} represents as much as possible of
> the population.
> - Have a runoff between w_1 and w_2.
>
> If w_1 is a strong winner, he'll win in the runoff. If he's a weak winner
> (e.g. the "bland politician being everybody's second choice" scenario), w_2
> wins.
>
> In IRV, this would be like running two-member STV where the IRV winner is
> barred from being disqualified.
>
> There could be a problem, though, in a society that has a bland centrist
> politician and strong left- and right-wing candidates. Since the runoff can
> only hold two candidates, either the left-wing or the right-wing candidate
> would be disqualified; and if the bland politician is sufficiently bland,
> then the wing candidate would pretty much win by default. IRV "solves" this
> by not letting center-squeezed candidates win in the first place. Another
> option is to have multiple candidates in the runoff, but then the simplicity
> and strategy resistance properties of the second round go away.
>