[Election-Methods] USING Condorcet

[Juho]

Ok, election with three candidates only is the most risky from burial  
point of view since then it is easy to identify the relative position  
of different candidates (one winner (A), one loser but powerful  
enough to try the strategy (B), one loser that is weak enough to be  
used for burial (C)).

My point is that in real life large public elections strategies are  
much more difficult to implement than in theoretical examples on  
paper. I'll list some points that indicate why burial is not very  
likely to happen or be successful.

- In most cases the set-up is not as clear as in the theoretical  
burial examples. There may be more than three candidates. The  
relative position of the candidates may be unclear.

- Use of the burial strategy indicates that the runner-up thinks he  
will lose. In a situation where there are two leading candidates of  
same strength burial would not make sense since the strategy can not  
be kept secret and supporters of both candidates would use it, and  
that would just elect C. I think I have actually never seen a runner  
up candidate that would indicate before the election that he will  
lose to the other main candidate (and therefore wants his supporters  
resort to strategic voting).

- A positive campaign for one's own candidate (and potentially  
negative against the competitors) is thus the typical case. Often  
even the C candidate presents himself as a potential winner all the  
way until the election day.

- If B is so far from victory that all his supporters may safely give  
up hope of winning the election and turn to the strategic plan he may  
already have too little supporters to run the strategy successfully.

- The available polls are inaccurate.

- The opinions are likely to change before the election (when  
compared to the available polls).

- The strategic candidate may lose votes due to the plot (depends a  
bit on the society and if it approves or disapproves the  
strategists). The campaigns of A and C will probably take maximal  
benefit of B's bad morale and B's tendency to give up the hope of  
victory already before the election.

- The leading candidate may gain extra votes since he is declared to  
be the leading candidate before the election. On the other hand  
elections are surprisingly often close to 50-50 at the election day  
(which would make the strategy again unwise).

- It is not possible to control the voting behaviour of thousands or  
millions of voters.

- It is possible that if too many B supporters will follow the  
strategy C will win. It is impossible to control the number of  
strategic voters when this risk exists.

- Many voters probably will not understand the strategy or are not  
listening and therefore will not follow it.

- Also some A and C supporters may follow the strategy.

- Many B voters may not use such strategy since they feel it is not  
right (also this may depends on if the society approves or  
disapproves the strategists).

- Many B supporters certainly believe that B will win (this kind of  
optimism is common and also strategically wise). It is not within  
their interest to declare B as a loser and resort to strategic voting  
and a corresponding campaign.

- The election is likely to contain all kind of votes. In the case of  
three candidates that means A>B, A>C, A, B>A, B>C, B, C>A, C>B, C,  
A=B, A=C, B=C. The preference strengths are also different, e.g.  
A>>B>C vs. A>B>>C. And the voters may have different rationale and  
morale. All this makes the system less easy to manage than in the  
clean cut theoretical examples.

- For many voters the risk of backfiring may be a reason not to use  
the strategy (the actual strength of C is unknown, possible use of  
strategy by the A supporters is unknown etc.).

I'll skip writing a concrete example this time since there is already  
plenty of text here. A detailed analysis with the numbers is complex  
due to the numerous uncertainties that I listed above.

Juho



On Jul 1, 2008, at 22:19 , Kevin Venzke wrote:

> Hi Juho,
>
> --- En date de : Mar 1.7.08, Juho <juho4880 at yahoo.co.uk> a écrit :
>> De: Juho <juho4880 at yahoo.co.uk>
>>> I don't entirely agree. I would rank below my
>> strategically-determined
>>> approval cutoff (if I suppose the same election could
>> be held also
>>> under
>>> Approval), but I wouldn't rank that much lower,
>> and I don't think
>>> other
>>> voters should either.
>>>
>>> Two reasons for this.
>>>
>>> 1. If you rank everybody and are predictably sincere,
>> burial strategy
>>> by other voters is more likely to succeed against you.
>> People who
>>> would
>>> use this strategy need to have doubt about what
>> you're going to do.
>>> Truncating at the (strategically determined) approval
>> cutoff is
>>> good at
>>> this: The main effect is that voters don't rank
>> all the frontrunners,
>>> and burial strategy works basically by assuming one
>> frontrunner will
>>> get support from another.
>>
>> Also heavy truncation is dangerous since that could lead
>> even to
>> extensive bullet style voting (and all the benefits of
>> Condorcet
>> would be lost).
>
> I don't suggest truncating any higher than the approval cutoff. It  
> should
> be safe to truncate somewhat lower than that.
>
> Anyway, whether truncation is a danger to the quality of the  
> results of
> the method is quite a different question from whether truncation is a
> danger to a specific voter. I think a voter would hardly ever be  
> harmed
> by truncating where I suggest (you're withholding support from options
> that you shouldn't need unless your information is bad), while they  
> help
> (over time) to create a deterrent to burial.
>
>> I also think that the probability of successful strategic
>> voting in
>> large public elections is very small in Condorcet.
>
> It doesn't have to be successful. Backfiring strategy is a problem  
> too. A
> given voter simply being able to imagine how the strategy could  
> work is a
> problem.
>
> If everyone is giving full rankings I think the latter is too easy.  
> Don't
> worry about the Wikipedia election, just take a simple scenario  
> with two
> frontrunners and a third, weak, undesirable niche candidate. If I  
> think
> everyone will give full rankings, then the only reason for me to  
> not use
> burial against the worse frontrunner is the possibility that his
> supporters will be using this strategy against my candidate.
>
> I should not be able to contemplate such a strategy just because of  
> the
> presence of a third, unviable candidate!
>
> In such a scenario, ranking all the alternatives would and should
> accomplish nothing (unless you support the third candidate). The only
> reason to ask these voters to do that is that it would be nice if  
> we could
> say it worked. As strategy advice in this scenario I think it is poor.
>
> Kevin Venzke
>
>
>
>        
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