[EM] MAV on electowiki
Abd ul-Rahman Lomax
abd at lomaxdesign.com
Sat Jun 29 10:31:54 PDT 2013
At 10:19 AM 6/28/2013, Chris Benham wrote:
>"...But I don't think it's realistic..."
>I don't think any of the "multiple majorities" scenarios are very
>realistic. Irrespective of how they are resolved,
>all voters who regard one or more of the viable candidates as
>unacceptable will have a strong incentive to top-rate all the
>candidates they regard as acceptable, out of fear that an
>unacceptable candidate gets a majority before their vote can help
>all the acceptable ones.
This is probably the opposite of what would happen. The pressure is
*heavily* toward majority failure, not multiple majorities.
Essentially, the comment assumes that a voter will think that another
candidate will get a majority in the first round before one of those
acceptable to them. This would indicate that those acceptable are not
frontrunners. While we have proposed to *allow* voters to vote for
more than one in the first round, that is mostly to avoid tossing
ballots for overvoting and to cover the rare situation that a voter
actuallyh does not know which of two candidates they prefer. Given
Bucklin amalgamation, it is *extremely unlikely* that voters with a
significant preference between A and B will vote for both in the
first round. The pressure to sincerely distinguish a favorite is high.
That largely vanishes after the first round completes without a
majority. Remember, it's rare that there are three viable candidates.
So, here, the voter only approves of one of them. Not two. If there
is a multiple majority in the first round, it's unlikely to be
outside of this set.
What is being said is that the voter strongly disapproves of one
viable candidate, so strongly that the voter wants to nail down,
absolutely do the utmost to prevent the election of this one, so the
voter approves of the other two, in the first round. I'd be amazed if
0.1% of voters actually voted that way, in a real election, outside
of this rare situation: the voter only knows the strong dislike for
one candidate, and is ignorant of all others, so votes antiplurality.
In that case, it would be a fair representation of the voter's
preferences. The problem is?
>I still say that your suggestion only increases that incentive (even
>though maybe more psychologically than likely to cause extra actual
We cannot prevent voters from making up irrational reasons to do this or that.
>Forget about using the mechanism for resolving the (probably very
>rare) multiple-majorities scenario to try to gain some whiff of
I came to the conclusion that the problem with MAV is that it loses
the Range winner, so it damages SU, and that could reasonably
commonly occur. Multiple majorities *did* occur in real Bucklin
elections, though only in second or third rank. I don't recall all
the specifics. Voting for more than one was locked out in original
Bucklin. If the problem described *did* occur, that would be a reason
for demoting first rank votes that were overvoted, they would get
pushed, for Bucklin amalgamation, into second rank. (Which would be
much better than considering them spoiled. Or even to third rank, if
it were decided to make the top two ranks vote-for-one. But I don't
like this. I'd tolerate the first rank limitation, but would still
leave a meaning for overvoted first rank, for ballot position
assignment, it would be split, i.e., a half-vote each if it was two.)
>BTW, the "Majority Choice Approval" Bucklin-like method using
>ratings (or grading) ballots, simply elected the candidate whose
>majority tally was the biggest. I also prefer that to your
>suggestion. It and yours are simpler to count than the Mike Ossipoff
>idea I support.
That is basically Bucklin-ER. It has the virtue of simplicity. Ranked
Approval voting, preponderance of the votes at the majority-found
rank, or as a plurality result if all ranks have been collapsed.
EMAV is the same except that the ranks are interpreted as ratings and
the multiple-majority or plurality standard is based on a range sum.
That automatically deprecates lower-ranked votes, without eliminating them.
More information about the Election-Methods