[EM] RE : Is "sincere" voting in Range suboptimal?

[Stephane Rouillon]

For more voters, it is not simple. For an optimal strategy, one that
would optimize the result form the voter point of view,
the question depends of the probability of the rest of the ballots.
Saying it's a no-information election is not sufficient.
Are non-extreme position like B2 A1 C1 or B1 A0 C0 equiprobable to
others?
Some would say they have a 0 probility but I doubt even if those cases
do not seem optimals (thus logicals) ...
(Other) voters are not always logicals...

But for the two-voters case, I have to agree with Chris analysis: the
sincere ballot is not the optimal strategy.
The truncated strategy is even dominant in the sense that there is no
case where the results is expected to be worse
according to the mean social utility (averaging ties).

With more voters it would not be the case because truncation could lead
to C wins, something that cannot happen with
two voters as A is always at least tied with C. Thus probabilities would
matter.

Could you (both Chris and M. Lomax) provide the other voters ballot
repartition you use according to your own no-information understanding?

S. Rouillon

Chris Benham a écrit :

>
>
> Abd ul-Rahman Lomax wrote:
>
>> At 09:48 AM 7/23/2007, Kevin Venzke wrote:
>>
>> > Are you going to argue that it should make no difference to the
>> > voter
>> > how likely it is that he will be able to change the outcome given
>> > some
>> > way of voting?
>> >
>> No, for if it is so unlikely as to be impossible, rational voting
>> strategy is to not bother to vote.
>>
> <snip>
>
>> What I am arguing is that a voter should properly assume that many
>> other people will vote as he votes. If the voter knows that
>> assumption is true, then there is always a reasonable chance that
>> the
>> voter's vote will shift the outcome, to the point where, if the
>> voter
>> and those like him are in the majority, the voter's vote, depending
>> on the method, may be *certain* to affect the outcome.
>>
>
> I find these two statements (before and after the cut) a bit
> contradictory.
>
>
>> The case I'm studying is zero-knowledge, Range 2, i.e., CR3. Three
>> candidates, voter's preference is A>B>C, with midrange sincere
>> rating for B.
>>
>> We now know that in the two-voter case, the optimal vote is sincere.
>>
>
> No we don't. The "optimal vote" in your scenario is to max-rate A and
> min-rate B and C.
> Comparing the two, the "truncated vote" beats the "sincere vote" in 3
> opposing ballot situations.
>
> (1)B2 A0 C0: the truncated vote gives an AB tie while the sincere vote
> elects B
>
> (2) B2 A1 C0: the truncated vote elects A while the sincere vote gives
> an AB tie.
>
> (3) B2 C1 A0: the truncated vote gives an AB tie while the sincere
> vote elects B.
>
> In all other cases the two give the same "voter satisfaction" score
> (by giving the same result in all
> except one:)
>
> B2 C2 A0: the truncated vote gives an ABC tie while the sincere vote
> elects B.
>
> Chris Benham
>
>
>
>
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