[EM] Condorcet question - why not bullet vote

[Juho]

Some more viewpoints that were not covered very well yet.

1) Typical (=all common) Condorcet methods make pairwise comparisons  
and derive the results from those comparisons. Changing one's vote  
from A>B>C to A>B=C does not change the pairwise comparison results of  
ones favourite (A) against the others. The second vote does say B=C  
although the true opinion of the voter is B>C. That helps C and hurts  
B when these two are compared (these might be the two strongest  
candidates, and not indicating one's opinion in this pairwise  
comparison could change the winner from (sincere) B to C).

2) There are few cases where not giving one's sincere opinion may  
improve the result. It is however a fact that in almost all situations  
giving one's sincere preferences is the wisest thing the voter can do.  
It is not easy to identify and efficiently use those exceptional cases  
in Condorcet elections. For a regular voter in large public elections  
sincerity is clearly the best strategy to follow.

Juho



On Jun 16, 2010, at 8:30 PM, Peter Zbornik wrote:

> Dear all, dear Markus Schulze,
>
> I got a second question from one of our members (actually the same  
> guy which asked for the first time):
> If I just bullet vote in a Condorcet election, then I increase the  
> chances of my candidate being elected.
> If I have a second or third option, the chances of my prefered  
> candidate to win is lowered.
> Q: In this case why should any voter not bullet-vote?
> I have some clue on how to answer, but not enough for an exhaustive  
> answer.
>
> My argument starts:
> If I vote for a candidate who has >50% of the votes, then it does  
> not matter if there is a second or third choice.
> If my prefered candidate A gets <50%  of the votes, then it makes  
> sense to support a second choice candidate B.
> However if the supporters of B only bullet vote, then maybe B's  
> supporters get an advantage over A?
> ... at this point I realize, that I don't know enough about  
> Condorcet and/or Schulze to answer the question.
>
> Why is it not rational to bullet vote in a Condorcet election if you  
> are allowed not to rank some candidates?
> I guess you have discussed this question a zillion of times, so  
> please forgive my ignorance.
>
> Maybe you could help me out with this one.
>
> Peter
>
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