[EM] Approval vs Condorcet. Voting in Approval.

[Chris Benham]

In a way Approval isn't a voting method, it's more like a voting 
"anti-method".

Voting methods have some algorithm.  They try to reduce the need for 
strategy, hopefully make some attempt to resist strategy, and (normally 
and hopefully)  give the voter the option of expressing their full 
strict ranking of the candidates.

Approval has no algorithm. It invites "strategy" and more-or-less relies 
on it to give a reasonable result.  Rather than give the voter a way of 
expressing their full sincere rankings, it confines the voter to 
choosing a set of candidates whose members they wish to uniformly and 
indiscriminately help versus the non-members.

It ensures "honest voting" by severely curtailing voter expression.

It's based on the assumption that voters only care about the effect of 
their votes on who wins and enjoy compromise-compression strategising.  
Obviously a huge improvement on the FPP "anti-method" but nonetheless 
understandably difficult for some people to get enthusiastic about.

There would still be some incentive for dishonest polls, trying to scare 
voters into approving unneeded Compromise candidates to guard against 
some Greater Evil.  But it is a great benefit that a rational voter can 
at least never be conned into not approving their sincere favourite 
(along with any other candidates they prefer to their Compromise candidate).

So "over the course of a few elections"  Approval would strongly tend to 
"zero in" on the Condorcet winner.  That is great, but the Condorcet 
supporter might well ask: "Why should we have to wait that long?".

Approval is a huge bang-for-buck contender, mainly by being almost no 
"buck".

Chris B.


On 26/05/2024 7:20 pm, Kristofer Munsterhjelm wrote:
> On 2024-05-16 08:04, Michael Ossipoff wrote:
>
>> I’m glad you brought up the desire for the method to do it all for us 
>> (as Condorcet does)…taking our sincere rankings as input, & 
>> outputting the legalistic right choice. …because I’ve been meaning to 
>> address that matter.
>>
>> …& that’s not even counting the much less expensive implementation 
>> (could be zero cost, without even needing new count-software), easier 
>> less expensive administration, & easier simpler explanation with 
>> consequent easier enactment.
>>
>> Approval isn’t as difficult to vote as it opponents claim. There are 
>> many ways to choose what or whom to approve. That variety is a good 
>> thing, because you can choose how you like.
>>
>> Condorcet is legalistic, but we don’t have to be legalistic! Approval 
>> guarantees election of the candidate who maximizes the number of 
>> voters for whom the outcome is in their preferred of the two 
>> merit-subsets, however the voter designates them.
>>
>> e.g. If people approve what they like, Approval maximizes the number 
>> of people who like the outcome.
>>
>> If people approve what’s acceptable, then Approval maximizes the 
>> number of people for whom the outcome is acceptable.
>>
>> If people approve above expectation, then Approval maximizes the 
>> number of people for whom the outcome is above expectation…maximizes 
>> the number of people pleasantly surprised.
>>
>> You don’t know the objectively-optimal vote? Neither does anyone 
>> else, so don’t worry about it!
>
> This makes it very hard to reason about or define any relative 
> properties about Approval, though, because it kicks the can down the 
> road to the voter instead.
>
> This is perhaps a bit exaggerated, but to show a point: does Approval 
> really pass clone independence? Suppose more candidates of a wing show 
> up, which embolden people to be more discerning than just approving 
> what's acceptable. Then the winner changes.
>
> Is "Approval"[1] *really* FBC, or monotone? If it converges to the 
> Condorcet winner, then nope, because you can't have FBC and Condorcet. 
> If it converges to the essential set, then nope, because the essential 
> set is nonmonotone.
>
> By saying "don't sweat it, people will do what they will do, there's 
> no objective meaning to the ballot except what the voters like", voter 
> behavior becomes so much more intermixed with the method. And then, 
> for criteria to compare apples to apples, they should take this 
> intermixing into account. Not being legalistic shouldn't let Approval 
> off the hook.
>
> But how?
>
> What I want is to have each method equally on the hook for what its 
> behavior implies. To paraphrase a reply I made to rb-j: if the winner 
> of an election can change when non-winners drop out, we don't really 
> care if the method passes IIA as such. It's a nice thing to have in a 
> box-ticking way, but that's it.
>
> If a method wants to open up the can of worms to say "nope, this 
> method isn't meant to be used in isolation, it's supposed to be used 
> with /whatever/ internal way of going from utilities to the types of 
> expression the ballot accepts", then okay, let's take it at face 
> value. Let's ask the questions that matter. Can this make someone lose 
> if some of the honest voters like the candidate more? Can it make a 
> non-winner change who the winner is?
>
> For ranking, this is easy, courtesy of the "legalism". For Approval, 
> not so much.
>
> -km
>
> [1] or rather, the method induced by iterating Approval or by 
> combining Approval with one or more thresholding strategies implicitly 
> chosen by a voter.
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