[EM] Total Approval Ranked Pairs

[Forest Simmons]

Date: Tue, 15 Mar 2005 21:49:20 -0800
From: Russ Paielli <6049awj02 at sneakemail.com>
Subject: [EM] Re: Total Approval Ranked Pairs
To: election-methods at electorama.com

Russ worried that putting in an approval cutoff might be too costly.

The cost is the same as adding one extra candidate, the ACC (Approval 
Cutoff Candidate).

Voters that truncate the ACC candidate are implicitly approving all of 
their ranked candidates, since any ranked candidate is considered to be 
ranked above all truncated candidates.

Russ went on to say that he wasn't too crazy about any of the proposed 
names for ARC/RAV.

If we want to beat IRV we have to get "majority" into the title.

I suggest that we call it "Definite Majority Choice" which would be 
consistent with the following description:

1. Rank as many candidates as you want. One of these candidates is the 
Approval Cutoff Candidate (the ACC).

2. For each candidate X  (besides the ACC)  count how many of the ballots 
rank X above the Approval Cutoff Candidate. This number is candidate X's 
approval score.

3. Now withdraw the ACC, which has served its purpose.

4. For each candidate X determine if there is another candidate Y with 
higher approval score than X, such that Y is also ranked higher than X by 
a majority.  If this is the case, we say that Y is definitely preferred 
over X, and that X is a definite majority choice loser.

[In Fine Print] By "majority" we mean a majority of those voters that 
express a preference between X and Y.

5. Eliminate all definite majority choice losers.

6. Choose as winner the candidate that is ranked above each of the other 
remaining candidates by a majority.

[In each case it is to be understood that the majority is a majority of 
those that express a preference.]


[End of method description]


What do you think?



Personally, I would rather see the last step replaced with

6'. Of the remaining candidates, pick as winner the one which is ranked 
highest on a randomly chosen ballot.

But I realize that the advantage of this version over the deterministic 
version is too subtle for the general voting public to appreciate.

But just for the record, I would call this stochastic version "Majority 
Fair Chance."

Perhaps the citizens of a country like Rwanda could appreciate the method.


Forest