The spoiler effect is a special case of non-monotonicity.
A general definition of a monotonic method is:
no voter or group of voter could harm a candidate by expressing its full
preference toward any higher preferred candidate.
While you restrict monotonicity definition to:
no voter or group of voter could harm its favourite by expressing its full
preference.
It is your choice. You chose to disregard the fact that winners, while the
voter expresses or not its full preferences, could both not be the favourite
of the voters.
I do not understand why you want to consider the spoiler effect as a
different problem. As soon any voter would learn that its first choice has
no chance of winning, its second choice would become its new first choice,
the spoiler effect leading again to your personal definition of the
monotonic dilemma...
Historically we gave it another name, but it is still a perticular case of
the same problem...
Sorry i am not impressed enough by your defense to use any capital letter
word....
Stéph.
PS: I do understand there are problems auditing preferential ballot systems.
However I am still convinced STV or STV-PR is the best system among those
actually used in the world. Why not stick to paper ballot with STV? I think
it would remove the auditing problems you hate. Irish people have been using
this system since 1929, no computers existing at the time. Even with an
explosion of candidates, it can be done using a pen, without centralizing
all the data, with simply enough communications between the election center
and the poll stations... All you need is to make sure that the election
result is the good one. Instead with computers you have to make sure that
the result for any election is the right one: a very complex job indeed...
From: "Kathy Dopp" <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
To: "Stéphane Rouillon" <[EMAIL PROTECTED]>
CC: [email protected]
Subject: Re: [EM] New MN court affidavits by those defending
non-Monotonicvoting methods
Date: Thu, 6 Nov 2008 21:26:06 -0700
Stephane,
You are confusing the spoiler effect with monotonicity.
Plurality voting is ALWAYS monotonic.
Neither IRV or plurality solve the spoiler problem.
Both are susceptible to strategizing. I don't know any voting method
that is not.
Does anyone have anything helpful to add?
Kathy
On Thu, Nov 6, 2008 at 9:03 PM, Stéphane Rouillon
<[EMAIL PROTECTED]> wrote:
> Again Kathy, it depends how you define monotonicity.
>
> With FPTP, you can easily let your third choice win by voting for your
first
> choice
> while you could have got your second choice elected by voting for him.
> But as you only want to consider monotonicity in regard to your first
> choice, you argue that FPTP is monotonic, which is right using that
> definition.
>
> Stephane Rouillon
>
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