On Fri, Apr 5, 2013 at 2:43 PM, Kristofer Munsterhjelm <km_el...@lavabit.com > wrote:
> On 04/05/2013 09:37 PM, Forest Simmons wrote: > > The following observation about Condorcet IRV Hybrids has probably >> already been made (but I have been gone for a while): >> >> These hybrids have no good defense against burying. For example >> >> Sincere ballots: >> >> 40 A>C >> 35 B>C >> 25 C>A >> >> If the A faction decides to bury C, there is nothing the C faction can >> do about it unilaterally. They have to depend on the willingness of the >> B faction to elevate their compromise over favorite. >> > > That's strange, because one of the points of James Green-Armytage in his > voting strategy paper was that the Condorcet-IRV hybrids were significantly > less prone to burying than ordinary Condorcet methods. Quoting, > > "All Condorcet-efficient methods are vulnerable to burying, but this > vulnerability seems to be substantially less frequent in the Condorcet-Hare > hybrids than in most other Condorcet methods. The reason for this is that > voters who prefer q to w will already have ranked q ahead of w, so that > further burying w will not affect w's plurality score unless q has already > been eliminated." > > ("Four Condorcet-Hare Hybrid Methods for Single-Winner Elections", > http://www.econ.ucsb.edu/~**armytage/hybrids.pdf<http://www.econ.ucsb.edu/~armytage/hybrids.pdf>, > p. 8) > > Or are we talking about different things? Perhaps C/IRV methods are less > vulnerable to burying in the first place, but when they are, it's harder to > employ defensive strategy to correct the burial? > > - > > Also, I seem to recall that Uncovered,X is generally more susceptible to > burial than is X for various types of X, unless X is already rather > susceptible to burial. It might be interesting to run a JGA type analysis > on your "eliminate until covering" method, and compare to the Smith-IRV > methods. > > The method I proposed is not of the type "Uncovered X." The first candidate to cover the remaining candidates may well be a covered candidate herself.
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