[Election-Methods] Fwd: RE : Corrected "strategy in Condorcet" section, Chris

[Kevin Venzke]

Chris,

Chris writes [regarding NWL]:
>For a two-round method that is certainly something simple and "intuitive"
that improves on standard
>plurality TTR.  I assume the details are "in first round vote for oneas
favourite and approve as many 
>as you like. FPW wins with FP score of 50% or more. Otherwisequalifiers
are FPW and most approved
>alternative candidate. (Of course "favourite" also counts as"approved").

Actually, if I remember correctly I considered this to be a fully ranked
method. You could specify more than one first preference.

And if the same candidate was the FPW and the AW then this candidate would
win. Otherwise there seems to be a needless monotonicity problem.

>Of course in this method voters who are confidant that their favouritewill
be the FPW have a big incentive
>to approve all the turkeys and conversely voters who are confidant
thattheir favourite will be the AW might
>have incentive to vote a turkey as their favourite.But I doubt that
therisk of both qualifiers being turkeys is as
>great in approval top-2, and all this attempted "turkey raising" mighthelp
minor parties survive. :)

That's something I wasn't thinking about back then, I guess. The ability
of FPW supporters to approve turkeys seems too great. I'm not worried
about AW supporters ranking turkeys as their favorite, though; this would
run a substantial risk of giving the race to them.

>For method that uses ranked ballots either in one round or in the firstof
two rounds, I prefer "elect the winner
>of the pairwise comparison between the IRV (Strict) winner and theApproval
winner".   That wouldn't have a
>clone problem, supporters of weak candidates would have no
"favouritebetrayal" incentive, and it would meet
>Majority for Solid Coalitions and Dominant Mutual Third.

I wonder if this method doesn't have a similar problem as NWL.

>>>... a potentially useful set:"the set of candidates whose approval score
is higher than  their  maximum approval opposition score".  
  
>>I think it's pretty interesting... I'm having trouble thinking through
>>these particular methods, but as a criterion it seems pretty good. Inote 
>>that in the 7 5 8 plurality failure example, again B is required.It 
>>reminds me of "pairwise plurality" (at least, my conception of it),where 
>>a candidate can't win if their worst loss is stronger than theirbest win.
 

>Notice that in your NWL example
>  
>7 A>B5 B6 C2 D>C
>the set is {B}, the winner by many of our preferred methods.  I inviteyou
>to suggest a name for this set.

Well, in my mind this concept has more to do with "acknowledgment" than
"approval." So I'd be more inclined to phrase it in terms of "voting for"
a candidate than "approving" one.

MD can be:
"If >50% vote for X and don't vote for Y, then Y can't win."

Plurality can be:
"If there are more first preferences for X than votes for Y, then Y can't
win."

This would be:
"If more people vote for X and don't vote for Y, than vote for Y, then
Y can't win."

I'm not sure what to call it... It's nice that it doesn't make reference
either to a majority or to first preferences, though.

Kevin Venzke


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