# [EM] MAMPO is probably better than MDDA

Forest W Simmons fsimmons at pcc.edu
Mon Mar 19 14:09:14 PDT 2007

```Chris, this reminds me of something related I suggested last December in

http://lists.electorama.com/pipermail/election-methods-electorama.com/2006-December/019070.html

under the title of

"[EM] carrying Warren's approval equilibrium idea to its logical
conclusion"

Here's an extract:

"... Among all candidates with  R(X) = M,  the winner is the candidate
X  with the greatest surfeit of approval

Approval(X) - MPO(X)  ..."

This is the same difference that you call the "score" of candidate X.

My objective was more ambitious ... to find the natural approval cutoff.

The unweighted difference seems right, because MPO(X) is an estimate of
the minimum number of voters that would put their approval cutoff just
above X if they thought that X was the most likely winner.

Forest

Chris Benham wrote ...

>Kevin,
>I'm interested in your opinion of my stab at something similar that
>meets Irrelevant Ballots:
>
>"1 and 2 as for MAMPO.
>3. Give each candidate a score that is equal to its approval score
minus
>its opposition score.
>4. Elect the candidate with the highest score".
>
>With sensible approval strategy, this seems to 'perform well' (in terms
>of strategic criteria) with 3 or 4
>candidates. The approval component seems to easily rescue MMPO from its
>greatest embarrassments.
>
>One hope is that the truncation incentive of Approval and the
>random-fill incentive of  MMPO will mostly
>cancel each other out.
>
>There may be some smarter way to combine approval and pairwise
>opposition scores, perhaps weighting
>them unequally. And if anyone likes it I'm open to a suggestion for a
name.
>
>Chris Benham
>
>
>
>>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.

```