[EM] Smith+IRV//Approval

[Colin Champion]

Chris - as I understand it, there's no reason to expect Condorcet voting 
to produce satisfactory results if applied seat-by-seat to 
representative assemblies. Some voting theory texts have a disclaimer 
near the beginning: "We here discuss the election of a single 
office-holder (eg. a president); election of individual members to an 
assembly brings in additional considerations" (which are never discussed).
    At any rate, if a country is governed by a parliamentary assembly, 
then the primary the aim of an election should be to produce an 
effective government whose policies are as close as possible to the 
consensus view of the electorate. This will not usually be achieved by 
giving each constituency a representative who is close to its local 
consensus.
    I made a proposal of my own a couple of years ago: 
http://lists.electorama.com/pipermail/election-methods-electorama.com/2021-October/003113.html 

     My main concern was to avoid the minority governments which 
generally arise when FPTP is replaced by less crude methods. As for 
traction... I'm still its sole supporter.
    Colin

On 17/09/2023 17:52, C.Benham wrote:
>
> I've been thinking a bit why the Condorcet has so little popular 
> traction, why some quite intelligent
> are wary of it and prefer IRV.
>
> Suppose we are talking about electing members of a parliament (or 
> legislature) in single-member seats.
>
> Typically the two largest parties, say one centre-left and and one 
> centre-right, will between them win nearly
> all the seats and with luck the one that is preferred by more voters 
> than the other will get more seats
> (and so in a Parliamentary system will form a government with its 
> leader becoming the Prime Minister).
>
>
> So in this limited sense the result is very very roughly 
> "proportional".  Assuming the small wing parties'
> supporters are normally spread out in lots of different districts, 
> they will get no seats.
>
> But suppose in a lot of the seats the contest looks like this:
>
> 47 A>>>C>B
> 43 B>>>C>A
> 10 C>A>>B
>
> If this is IRV  or FPP then A easily wins, but the CW is C.
>
> But A is clearly the highest "social utility" candidate, and assuming 
> that voting is voluntary and at
> least somewhat inconvenient or costly, then C has only been voted the 
> CW because both A and B
> are on the ballot. If one of those candidates wasn't, then most of his 
> or her supporters would stay
> home and allow the other to easily beat C.
>
> And if something similar (electing a weak centrist that most of the 
> voters don't like) happens in enough
> seats it could result in the "weak centrist party" being grossly 
> over-represented in the legislature.
>
> So to allay these fears I suggest this compromise with IRV: 
> Smith+IRV//Approval:
>
> *Voters strictly rank from the top however many or few candidates they 
> wish.  Default approval is only
> for the top-ranked candidate, but voters can extend approval to one or 
> more other candidates by marking
> the lowest-ranked candidate they approve.
>
> Elect the most approved candidate that is either in the Smith set or 
> is the IRV winner.*
>
> Allowing above-bottom equal-preferences (at least without a lot of 
> extra complexity) makes Push-over strategising
> easier.
>
> So in the type of example I just discussed the IRV winner would 
> normally have a much higher approval score
> than the CW, but the supporters of the IRV runner-up could change that 
> if they like by extending their approval
> to the CW (who then might win, especially if the CW's supporters 
> refrain from extending their approval to the IRV winner).
>
> Chris B.
>

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