[EM] Juho reply

[Michael Ossipoff]

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.

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.

Juho continues:

I also find the path based explanations a bit clumsy

I reply:

Yes, I don’t use path-based explanations or justifications. Though 
BeatpathWinner is equivalent to Cloneproof SSD, I prefer to offer Cloneproof 
SSD defined by its own procedure rather than by BeatpathWinner’s procedure. 
In public elections, with no pair-wise ties, SSD is equivalent to CSSD and 
BeatpathWinner. I offer SSD because it has a more natural and obvious 
procedure than CSSD or BeatpathWinner.

Juho continues:

…better than just saying that there was a cycle (people don't understand 
what that is)

I reply:

One thing I  and others like about SSD is that it makes no mention of 
cycles.

I agree with Juho that when Plain Condorcet elects a Condorcet Loser, it is 
a peculiarly popular Condorcet Loser, and not as bad an outcome as some 
might claim. I don’t object to Plain Condorcet, though I’d like to have all 
four of the majority defensive strategy criteria, which PC doesn’t offer. As 
I was saying, “Minmax isn’t a good method name, because it’s used with more 
than one meaning.


Juho continues:

Let's cover also the strategy related aspects.

I reply:

With most Condorcet versions other than wv (and this is probably true of 
PC(margins) ),
Some voters who truncate the CW, whether due to carelessness, laziness, lack 
of time, or strategic motives, can steal the election. That truncation, in 
such method, can be used as an offensive strategy. But, whether or not it’s 
offensively strategically intended, it causes a defensive strategy need that 
doesn’t exist in wv. The defensive strategy criteria and wv Condorcet were 
proposed for a reason.

Juho continued:

I also don't like discussions on counter strategies in association with 
Condorcet. One of the key benefits of Condorcet methods is that people can 
give their sincere opinions.

I reply:

That’s much more true of wv Condorcet.

Juho continues:

If we go for (counter) strategic votes in Concorcet methods, large part of 
their benefits are lost. In summary it would be good to use Condorcet 
methods in environments where their natural strategy resistance gives good 
enough protection and everyone can trust that the elections will not lead to 
anything catastrophic (some small number of "uneducated" strategic votes 
will probably always be present, but hopefully not leading to problems).

I reply:

I agree that the advantage of Condorcet, possessed by its wv versions, is 
that counterstrategy would rarely be needed. And, if there’s a danger of 
offensive order-reversal, it’s countered and deterred by mere defensive 
truncation.

I suggest ARLO and power truncation for if, some time after Condorcet is 
adopted, there begins to be concern about offensive order-reversal strategy. 
I don’t suggest ARLO and power truncation for a first Condorcet proposal. 
And they’d probably never be needed.

Juho continues:

My explanations are leaning in the direction that all Condorcet methods are 
quite strategy resistant

I reply:

They’re not equally strategy resistant. 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).

Juho continues:

…Therefore it may be a good idea to pick a Condorcet method that has good 
performance with sincere votes.

I reply:

But you’ve got to get the sincere votes, and wv encourages sincere votes 
better than other Condorcet versions do.

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.

Mike Ossipoff


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