Re: Constitutional amendment: Condorcet/Clone Proof SSD vote tallying

[Andrew Pimlott <andrew@pimlott.net>]

On Mon, May 26, 2003 at 03:46:37PM +1000, Anthony Towns wrote:
> Yes, that's true. There are two responses to this: one is that the
> benefits are worth the risks; the other is that (hopefully) the incentives
> to vote honestly

which are ... ?

> The only time voting against an option that only requires a simple
> majority is useful is if you can arrange for "A beats B, D beats A,
> B beats D" to be the outcome, thus getting A dropped, and B winning.
> However, to manage this, at least some proportion of the majority that
> thinks "A beats B" voters has to prefer making no decision to *either*,

?  As far as I can see, all you need is enough D voters that B
voters can cause D beats A.

> at least we're acting on the votes we actually receive.

I believe that's true of most voting systems.  :-)

> The question is whether, in particular (realistic) circumstances, some
> given strategy is more likely to produce a favourable outcome than
> voting sincerely.

... and also more likely than if a plain Condorcet method were used.
Which complicates the analysis, because it's easy to construct cases
where B voters can beat A with strategy under both Condorcet+SSD and
"approval+Condorcet+SSD".  Here is a situation in which they are
different:

                sincere         strategy by BAD

                9 ABD           9 ABD
                6 BAD           6 BDA
                3 DAB           3 DAB
                2 DBA           2 DBA

Condorcet+SSD   A               A
approval+       A               B

(Maybe this is the sort of situation you were referring to above?)

This does not answer the question, but I think it's a fairly strong
data point.

Andrew