[EM] "Guaranteed Majority criterion" on Electowiki

[C.Benham]

http://wiki.electorama.com/wiki/Majority_Choice_Approval#Criteria_compliance

> MCA-AR satisfies the Guaranteed majority criterion 
> </wiki/Guaranteed_majority_criterion>, a criterion which can only be 
> satisfied by a multi-round (runoff-based) method.


http://wiki.electorama.com/wiki/Guaranteed_majority_criterion


> The *guaranteed majority criterion* requires that the winning 
> candidate always get an absolute majority </wiki/Absolute_majority> of 
> valid votes in the last round of voting or counting. It is satisfied 
> by runoff voting </wiki/Runoff_voting>, MCA-AR </wiki/MCA>, and, if 
> full rankings are required, IRV </wiki/IRV>. However, if there is not 
> a pairwise champion (aka CW), there could always be some candidate who 
> would have gotten a majority over the winner in a one-on-one race. 
> Since, unlike most criteria, this criterion can depend on both 
> counting process and result, there could be two systems with identical 
> results, with only one of them passing the guaranteed majority criterion.
>

This is an example of what Mike Ossipoff used to rightfully excoriate as 
a "rules criterion".

To me if  "two" voting systems/methods always give the same results with 
the same impute, then they are really
just one method (which perhaps has alternative algorithms) and so they 
both meet and fail all the same (non-silly)
criteria.

A voting method criterion should relate to some desirable standard.   Is 
IRV  that doesn't allow truncation somehow
better that IRV that does?

Why can't normal IRV (that allows truncation) just have a rule that says 
that exhausted ballots in the "last round of
counting" are no longer "valid"? 

Or better yet, since IRV meets Woodall's Symmetric Completion criterion, 
why can't it include a rule that all ballots
are "symmetrically completed" so then the winner in the "final round of 
counting" will certainly have an "absolute
majority of valid votes"?


Chris Benham


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20101104/b2c5eaa0/attachment-0002.htm>