[EM] Evaluative Majority Approval Voting

Abd ul-Rahman Lomax abd at lomaxdesign.com
Fri Jun 28 08:06:10 PDT 2013

The other day I sent this post to the mailing list for the Center for 
Election Science (electionscience at googlegroups.com). Comments are very welcome.
Okay, from discussions on the EM list, I've come to a method that 
seems practically ideal to me. We can call it EMAV, Evaluative 
Majority Approval Voting.

It uses the fact that a Bucklin-ER ballot, sanely voted, represents a 
descending approval cutoff; therefore the ballot

1. Expresses approval explicitly for all candidates so categorized.
2. Expresses preference *strength*, tied to approval cutoff, which 
is, from a common suggested approval strategy, rooted to election expectation.

The method:

1. Ranked ballot, with three approved ranks, one explicit disapproved 
rank, and default maximally-disapproved rating for blanks.
2. The ranks are ratings, with values of 4, 3, 2, 1, with 0 being 
default. A rating of 2 or higher is approval. (so rank number is the 
inverse of rating.)
3. Voters categorize candidates into categories, corresponding to the 
ranks (ratings), and may categorize as many candidates as they choose 
into each category. Categories may be empty.
4. The count of all legal ballots is the basis for "majority."
5. MAJORITY SEEKING. Canvassing begins with the first rank. If a 
majority of voters have so categorized a candidate, and no other 
candidate, the election is complete and that candidate wins. If more 
than one candidate has a majority, see the Evaluation process.
6. If no candidate has a majority in the first rank, the number of 
second rank votes is added in to the previous sums, and majority 
support is again tested as with the first rank.
7. If no candidate has a majority in the first and second ranks 
combined, the number of third rank votes is added in to the previous 
sums, and majority support is again tested, as with the first rank.
8. EVALUATION. Vote evaluation is performed if there is no majority, 
or if the above process finds more than one candidate with a majority 
at a rank amalgamation. For each candidate, all the cast votes are 
summed, using the rating values. If there are multiple approved 
majorities, from the prior process, the winner is the 
majority-approved candidate with the highest sum of ratings. If there 
is no majority approval, the winner is the candidate with the highest 
sum of ratings.


This method is "almost Range." In a runoff system, with runoff 
conditional on lack of majority approval, it could send top approval 
and top range candidates to the runoff. It could also be pairwise 
analyzed to send a Condorcet winner to the runoff.

As a runoff method, the voters will now presumably be much better 
informed about the candidates. The candidate set will likely be 
reduced. This method is safe from ordinary Favorite Betrayal in a 
runoff. (There are very unusual situations that could require 
strategic equal-rating, they involve multiple majorities. In the 
primary, there are other rare situations where some level of 
strategic voting is required; intrinsically, the way that many define 
"strategic voting," any use of "election expectation" is "strategic." 
In a runoff system, voters would presumably vote conservatively as to 
adding additional approvals, those with strong preferences. That's 
rational and *does express real perference strength.* That includes 
"bullet voters," based on only knowing the Favorite. A runoff gives 
these voters a new look at the candidates. If someone the best 
candidate is not nominated for the runoff, a write-in campaign would 
be based on actual knowledge of voter preferences. A Condorcet 
winner, for example, if Condorcet testing is not done, could still be 
visible from the votes if they are all reported, and if those 
preferences are maintained, and voted with knowledge, this candidate 
should win the runoff.)

If there is Condorcet failure with this method, it is likely to be a 
case where the Condorcet winner is *not* optimal.

The canvassing is simple to understand, I suspect. This is Bucklin, 
purely, unless there is majority failure, or a multiple majority, in 
which case it becomes Range (completely or within the majority-approved set).

This method could, of course, be trivially adapted to use more rating 
categories. I suggest that they always be balanced between approvaed 
and disapproved ratings, with midrange being considered "barely" 
approved, if it is Range N, N being even. If N is odd, then there is 
no midrange rating.

Unless the previously suggested overrating method is used to allow 
half-ratings. (This method would allow a voter to express 
half-ratings by voting two adjacent ratings. It handles what would 
otherwise be overvotes by counting the vote at the average of the top 
and bottom rating expressed.)

So if the method used a Range 9 ballot, voting the ratings of 4 and 5 
would be considered a vote of 4.5, thus midrange, and a 'stand-aside' 
approval. This is a trick for almost-doubling the resolution of a 
range method. Explicit zero might be added to the ballot if this is 
used, that would then allow doubled disapproved rating.

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