[EM] Anyone got a good analysis on limitations of approval and range voting?

[Raph Frank]

On Tue, Nov 10, 2009 at 10:52 PM, Kristofer Munsterhjelm
<km-elmet at broadpark.no> wrote:
> In the context of SEC, it would be:
>
> Voter submits two ballots - one is ranked and the other is a Plurality
> ballot. Call the first the fallback ballot, and the second the consensus
> ballot.
>
> If everybody (or some very high percentage, e.g. 99%) votes for the same
> consensus ballot, it wins. Otherwise, construct a Condorcet matrix based on
> the fallback ballots. Pick two candidates at random and the one that
> pairwise beats the other, wins.

How do you pick the random candidates?

For that to be clone independent, there would actually need to be 3 ballots:

- consensus ballot

If more than X% of the ballots pick the same candidate, then that
candidate wins.

- nomination ballot
- fallback ranking

2 nomination ballots are picked to decide the candidate and the
pairwise winner according to the rankings wins.

However, as I said in my last post, the nomination ballot isn't strategy free.

> To my knowledge, Random Pair is strategy-free. It might also be
> proportional, but I'm not sure about that (partly because I'm not sure how
> you'd define "proportional" for ranked ballots).

The problem is picking the 2 candidates.  If 2 are picked at random,
then the method isn't clone independent.

Also, it favours the condorcet winner, so may suffer from tyranny of
the majority.

However, if you had a divided society, then both ethnic groups would
still have some say.

For example, if the split was 55% (A) and 45 (B), and each ethnic
group only voted for their own candidate, then the results would be

2 A's: 30% => ethnic group A wins
A+B:  50% => ethnic group A wins (as they are the majority)
2 B's: 20% => ethnic group B wins

Thus group B gets some power, but not proportional power.

However, once the society starts working better, it would seamlessly
transition to a near condorcet method.

Also, in a divided society condorcet voting might reduce the issue directly.

In both cases, there would be an incentive for politicians from ethnic
group A to try to get support from voters in ethnic group B.

OTOH, a random election method may not be the best plan in a society
where corruption is a problem.