[EM] MAMPO is probably better than MDDA

[Chris Benham]

--- Kevin Venzke <stepjak at yahoo.fr> wrote:

> Hi.
> 
> This is the definition of MAMPO:
> 
> 1. A candidate's opposition score is equal to the
> greatest number of
> votes against him in any pairwise contest.
> 2. The voter ranks; those ranked are also
> "approved."
> 3. If more than one candidate is approved by a
> majority, elect the one
> of these with the lowest opposition score.
> 4. Otherwise elect the most approved candidate.
> 
> MAMPO satisfies FBC, SDSC, and SFC like MDDA does.
> But MAMPO also satisfies
> Woodall's Plurality criterion.
> 
> Woodall's scenario showing that MDDA fails the
> latter:
> 
> 20 ab
>  5 ba
> 24 bc
> 24 ca
>  9 dab
>  9 dbc
>  9 dca
> 
> "a,b,c are preferred to d by 49,49,48 voters
> respectively, which are not
> majorities, but a>b by 62, b>c by 67 and c>a by 66,
> so that a, b and c
> are all disqualified.  Thus MDDA elects d.  But d
> has 27 votes in total,
> and so is debarred by b who has 29 first-preference
> votes."
> 
> MAMPO manages to elect B since D lacks majority
> approval, and 62 is
> the lowest maximum such score.

Kevin,
I see that the example can be slightly modified, for
example by changing one of the 24 bc ballots to bca,to
show that MAMPO fails Definite Majority (because MAMPO
would still elect B, while A both pairwise beats B and
is more approved than B).

MAMPO seems to be very good for a FBC method, but I
prefer Definite Majority and Condorcet to FBC.

MAMPO invites comparison with Brahms-Sanver (or
perhaps a reduced version that like MAMPO doesn't
allow voters to rank among unapproved candidates).
It elects the candidate that is majority-approved and
pairwise beats all other majority-approved candidates,
and if there isn't one then the Approval winner.

Like MAMPO it fails Condorcet and Irrelevant Ballots
and meets Plurality, but unlike MAMPO it fails FBC but
meets Definite Majority.

But in my view the best of the methods that uses plain
ranked ballots and interprets all ranked (or ranked
above bottom or equal-bottom) candidates as approved
is ASM(Ranked).


http://wiki.electorama.com/wiki/Approval_Sorted_Margins

It meets Definite Majority, Smith,and Irrelevant
Ballots. I prefer it to Winning Votes or Margins.

I'm having trouble with my home computer, but I hope
to have more to say soon. BTW, what exactly do the
letters in "MAMPO" stand for? "Majority-Approved
MinMax Pairwise Opposition"?
> 
Chris Benham
> 
> 	
> 
> 	
> 		
>
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