[EM] new working paper: "Four Condorcet-Hare hybrid methods for single-winner elections"

[Kevin Venzke]

Hi Kristofer,

--- En date de : Sam 19.2.11, Kristofer Munsterhjelm <km-elmet at broadpark.no> a écrit :
> > Well actually it's LNHelp that gives you immunity to
> burial. (DSC, QR, and
> > MMPO are vulnerable in varying ways.) And sadly it
> seems to me that the desirability of having other voters
> doubt that you will express a certain
> > lower preference, mitigates the advantage of LNHarm.
> > 
> > If you look at LNHelp instead you will probably start
> out with Condorcet//Approval, which actually is one of my
> favorite methods due to
> > anti-burial properties. Maybe DAC is of interest too.
> 
> If that's the case, then LNH isn't enough. See Armytage's
> strategy paper, http://www.econ.ucsb.edu/~armytage/svn2010.pdf . In it,
> Bucklin is shown to be vulnerable to burial (e.g. page 28).
> This is quite strange because Bucklin isn't
> Condorcet-efficient and so could (and does) meet LNHelp
> outright.
> 
> It also seems possible to bury using Bucklin. Say that your
> sincere preference is A > B > C > D, and that B
> wins in the second round, but if you could somehow keep B
> from winning, then A would win in the third. Then
> dishonestly burying B, say by voting A > C > D > B,
> would help.

Hm, interesting. I agree then, that LNHelp isn't enough. It only covers
the situation of adding new preferences in order to bury, not rearranging
preferences.

> A method that passes LNHarm doesn't have this problem,
> AFAIK, because later preferences cannot harm your earlier
> preferences. Your chance of having A win is the same whether
> you vote A > B > C > D or A > D > C > B.

But LNHarm is still open to the problem that LNHelp prevents: Adding an
insincere lower preference where there was none.

IRV and FPP are totally immune due to satisfying both criteria, it seems
to me.

Kevin