[EM] Juho reply

[Juho]

On Feb 20, 2007, at 15:39 , Michael Ossipoff wrote:

> Juho wrote:
>
> My sympathies towards minmax(margins) come primarily from the way  
> it handles sincere votes.
>
> I reply:
>
> But there won’t be sincere votes for it to handle, to the extent  
> that it doesn’t allow sincere votes. That’s why the defensive  
> strategy criteria, and the wv Condorcet methods were proposed.

Do you mean that margins would be so "strategy inviting" that most  
voters would turn to strategic voters (in practical real-life  
elections) if margins are used? And that WV would solve that? (I'm  
under the impression that this kind of impacts are not very big and  
that they may work in both directions.)

> Juho continues:
>
> Elect the candidate that would beat all the others. If there is no  
> such candidate, elect the one that would need least additional  
> votes to beat the others.
>
> I reply:
>
> That sounds similar to Dodgson. If it’s Dodgson, or like Dodgson,  
> it is vulnerable to clones, and it doesn’t meet the defensive  
> strategy criteria.

I think Dodgson counts the sum of defeats. I'm not talking about  
that, just basic minmax(margins) (that actually implements  
"additional votes needed to become the Condorcet winner").

> “Minmax isn’t a good method name, because it’s used with more than  
> one meaning.

Also with other meanings than minmax(margins), minmax(winning votes)  
etc?

> The defensive strategy criteria and wv Condorcet were proposed for  
> a reason.
...

As I already mentioned I don't like counter strategies to much. If  
real-life elections end up in media and parties proposing various  
counter strategies to voters one day before the election (to  
strategies that some groups are planning or might try) I'm sure that  
election method would receive some criticism. I'm more interested in  
methods where strategic voting stays at levels where no counter  
strategies need to be considered (and where strategies are not a  
serious risk in the first place).

> The wv Condorcet versions are much more free of strategy-need, and  
> much more resistant to offensive strategies (for instance,  
> offensive truncation isn’t a problem in wv  Condorcet).

There are also examples in the other direction.
- Sincere votes: 49:A, 49:BC, 1:CB => B wins
- Strategic votes: 49:A, 49:BC, 1:CA => C wins if winning votes are used

I however hope that we are discussing rather small differences in  
strategic performance here (since my basic thinking is that Condorcet  
methods are at their best in situations where strategic voting will  
not become a major issue due to the natural strategy resistance of  
all Condorcet methods).

> Juho continues:
>
> The criteria also would force me to discuss the difficulty of  
> implementing the strategies, the probability of success, the  
> probability of certain vulnerabilities to appear in real elections  
> etc.
>
> I reply:
>
> Criteria don’t force you to do that. They tell, in brief and simple  
> language, what will never happen, or what will always happen, with  
> a method. They speak only of kinds of outcomes having a probability  
> of zero or unity.

Yes, good criteria are exact. But too often I see argumentation that  
refers to scenarios that are possible in theory but that maybe never  
occur in practice and/or whose impact is minor and/or requires lots  
coordination, many strategic voters, has risk of failure etc.

Juho


		
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