[EM] SFC and "margins vs. winning votes"

[Russ Paielli]

Kevin Venzke stepjak-at-yahoo.fr |EMlist| wrote:
> Russ,
> 
> I hesitate to respond to this, as I get the impression you just want to
> oppose all of Mike Ossipoff's ideas.
> 
>  --- Russ Paielli <6049awj02 at sneakemail.com> a écrit : 
> 
>>Here´s the actual definition of SFC:
>>
>>SFC:
>>
>>If no one falsifies a preference, and if a majority prefer the CW to 
>>candidate Y, and vote sincerely, then Y shouldn´t win.
>>
>>[end of SFC definition]
>>
>>Here's my comment:
>>
>>Mike considers this criterion critical and uses it as evidence that 
>>certain Condorcet variations are less vulnerable to insincere strategy 
>>when they base defeat strength on "winning votes" rather than "margins."
> 
>  
> 
>>If no one falsifies a preference, and if the margin of the victory of 
>>the CW over candidate Y is larger than any other margin of victory, then 
>>Y shouldn't win.
>>
>>[end of margins SFC definition]
>>
>>Does it now appear that margins is less vulnerable to strategy than 
>>winning votes?
> 
> 
> Your SFC is pretty absurd. It says that the loser of the strongest contest
> (by margins) can't win if that loss is to the CW.

I'm not sure what you mean here by absurd. Are you suggesting that a 
method's failure to pass "my" SFC is nothing to be concerned about, or 
are you suggesting that Condorcet wv can pass it?

> Mike's SFC says a majority of the voters don't need to do anything fancy
> to elect the CW. I can't see what or to whom your criterion makes a
> guarantee.

First of all, Mike's SFC is based on the assumption that no preferences 
are falsified. If that is not true, then it makes no guarantee to 
anyone. The voters who sense their preferred candidates have little 
chance of winning may well decide to try their luck with falsified 
preferences.

Beyond that, who says that a criterion must make a guarantee to someone 
or some group in particular? All it needs to do is make a statement that 
can be true or false about particular election methods.

> 
>>If you argue for wv, you are claiming that a 51-49 victory is "stronger" 
>>than a 49-0 victory. Common sense tells us that's nonsense. Some of us 
>>still have common sense.
> 
> 
> Forget "stronger"; the question is which one will you ignore if you have to
> ignore one of them. You can't toss out 51-49 over 49-0 without making guesses
> about the sentiments of the abstaining voters in the latter contest.

That depends. I could say that the votes of abstaining voters should be 
split evenly between the two candidates because they "ranked" them 
exactly equally by default. After all, if they considered one the 
candidates even the slightest bit better than the other, they could have 
voted that preference, but they chose to not do so. So I could argue 
that I am not making any "guesses" at all. I'm just taking their 
non-ranking to its logical conclusion. I'm not claiming that this is 
necessarily the best or only valid procedure, but I *am* claiming that 
it would be a valid and logical procedure. Of course, the voters would 
need to have that explained to them in advance.

--Russ