[Election-Methods] Matrix voting and cloneproof MMP questions

[Rob LeGrand]

Kristofer Munsterhjelm wrote:
> You use movie site data for your AAR-DSV examples. Does AAR-DSV
> manipulability mean that a movie site that uses it would face
> difficulty telling users which movie is the most popular or highest
> rated? The manipulability proofs wouldn't harm them as strongly (since
> very few users rate all of the movies), but they would in principle
> remain, unless I'm missing something...

It all depends on what we assume the voters would be trying to do.  If
each voter is trying to move the overall rating of each movie as close as
possible to his/her ideal rating of that movie, without any regard to how
the other movies are rated, then AAR DSV is completely nonmanipulable.
On the other hand, if a voter is trying to affect which movie ends up
with the highest rating, voting insincerely may sometimes give an
advantage.

--
Rob LeGrand, psephologist
rob at approvalvoting.org
Citizens for Approval Voting
http://www.approvalvoting.org/