[EM] FBC comparison: WV, margins, MMPO, DMC

[Adam Tarr]

On 9/10/05, Jobst Heitzig <heitzig-j at web.de> wrote:

the straightforward counterstrategy for those who prefer B to C is easy and 
> requires no insincere rankings (as would wv require): They just need to vote 
> their sincere rankings and approve of B and everything above B.


How is this more insincere than the option in winning votes? Why is 
insincere equal-ranking more insincere than insincere approval? This seems 
like a value judgement that can't really be supported. The two forms of 
insincerity are not really comparable.

I said so various times, but you continue talking about the 17% alone 
> without considering the whole situation. Obviously, when we are talking 
> about counterstrategy, the relevant group of voters is those who prefer the 
> sincere winner to the manipulated winner, in this case all who prefer B to 
> C. This group has in DMC a sincere counterstrategy, but needs insincere 
> equal-ranking in winning votes.


The reason you look at a subgroup is because you want to figure out the 
optimal strategy for an individual voter. A voter can only decide his or her 
own vote, not the vote of all who share a particular pairwise preference or 
even all like-minded voters. The analysis I did shows that _each individual 
voter_ in that faction has the incentive for favorite betrayal.

I consider it considerably less relevant what kind of counterstrategies some 
> small and special subgroup of those who prefer the sincere winner has.


In my opinion, considering the incentives of individual voters is the most 
fundamental building block of strategic voting analysis. Why may we ignore 
the favorite betrayal need of a large number of voters? Just because some 
other voters who share one pairwise preference with them have not voted in 
he way that our faction would like? Can you imagine explaining that to the 
voter?

"Yes, you need to bury Nader below your approval cutoff so that Gore can 
win. But it's not a big deal. It's just because some other Nader supporters 
won't approve Gore, and because some Gore voters approved Bush. It's their 
fault for being non-strategic. It's not the method's fault. You're just 
cleaning up the mess they made."

All favorite betrayal incentives are significant, even if there is another 
strategy for a majority that could avoid it! The only thing worth debating 
in my opinion are how often the situation would arise, leading to the 
question of how much of a problem it really is.

Regards,
Adam
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