[EM] PR for USA or UK

[Kevin Venzke]

Hi Toby,

--- En date de : Dim 24.7.11, Toby Pereira <tdp201b at yahoo.co.uk> a écrit :
[begin quote]
>>Strategy-resistant systems do have certain advantages as you say, 
>>but in the single-winner case it would end up reducing range to a 
>>Condorcet method, which arguably isn't as good, and ends up pushing 
>>out a "better-liked" candidate for one that strictly more people 
>>prefer. And this is what I like about range - it's not just about 
>>which candidates you prefer to which other ones, but by how much. 

>I think the Range method itself is pretty incapable of this, but you
>could do it either with rated ballots or with a rank ballot that has
>truncation incentive.
 
Is a range ballot not a rated ballot?
[end quote]

Sorry, I mean, I don't believe it is hopeless to try doing what you
want with a rated ballot. Range does use a rated ballot. Off the top
of my head I don't have any really great method suggestions here,
because it seems to me to be extremely difficult to design a method so
that it maximizes utility. If the method is strategy-proof, it will
tend to elect the sincere Condorcet winner. If it's not strategy-proof,
you can't fully trust the information you collect. Something in-between
seems to be needed, but I would bet nobody will feel very happy with 
whatever is invented.

[begin quote]
>>And as long as strategy isn't performed better by voters of some >candidates than others, the fact that there would still be some 
>>honest voters would mean that the advantages of range would still 
>>remain to an extent, meaning that overall better-liked candidates 
>>stand a better chance, and it therefore reflects better the overall
>>preferences of the electorate!

>That paragraph makes sense if you're comparing Range to Approval, but 
>not Range to anything else. If large numbers of voters use strategy in
>Range (and I'm pretty sure they would be encouraged to; personally I
>wouldn't need any encouraging) this will destroy so much information 
>that the only way Range will win out is if the rank methods you compare
>it to contain even more destructive incentives than Range has.
 
With a single-winner election, the full strategy option is to vote approval style, but I'm not sure if this is as clear for PR.

[end quote]

No, I have no comment on any PR versions. I wouldn't assume any 
similarity.

>You say you wouldn't need any encouraging to vote strategically -
>I wouldn't either to be honest - but what is the optimal strategy?

I have heard and tend to agree with "approve everyone better than what
you expect on average the outcome to be." If there are two frontrunners
with perceived-to-be equal odds of winning, that would mean approving
every candidate better than the average of the two.

Experimentally there usually are two frontrunners that emerge from
pre-election polling.

In my own simulations, the ideal strategy is determined by the voters
within the specific situation they find themselves in. So it's not
easy to describe what strategy they are choosing, but it must be 
something close.

>In any case, if range does turn out to be problematic, proportional
>approval voting would be my next choice. I don't like ranked ballots
>because you don't know how much the voter actually likes each 
>candidate or whether they like them at all.

Generally I have liked rank methods where voters are not thought to be
supposed to rank candidates they don't really like. This may start to
turn it into Approval, but with some ranking information retained.

>>Can you explain your position without saying "party"? Because if you 
>>didn't see the parties, and only saw voters, it would be indefensible 
>>to give a seat to the 32%. There would be nothing special about that 
>>group.
>
>Candidates A and B are both fairly similar and 68% of voters vote 
>for both of these approval-style and no-one else. Candidates C and 
>D are also similar to each other and 32% of voters vote for both 
>of these approval style and no-one else. That's the example set out 
>without parties.

Ok. It sounds like you want to represent more "types" of voters. The
68% cannot have both seats because they're the same "type." If they were
different types then it would be OK.

Kevin Venzke