[EM] Fw: Deterministic Epsilon Consensus Idea stimulated by a question of Steve Bosworth (was Election-Methods Digest, Vol 207, Issue 9)

steve bosworth stevebosworth at hotmail.com
Wed Oct 6 21:49:35 PDT 2021


TO: Forest
FROM: Steve

Thank you for forcing me to see that no voting method, including MJ, can "guarantee" that its winner will be supported by an absolute majority of all the ballots cast. MJ guarantees this only if an absolute majority of all the ballots cast for at least one candidate have awarded them a grade of at least Acceptable. Otherwise, the MJ winner is the candidate who has received a plurality of such grades.

In these circumstances, electing this plurality candidate is justified by the democratic assumption that other things being equal, a candidate with more votes than other candidates is probably more suited for office. For the same reason, an absolute majority candidate is probably more suited than a winning candidate with less support than a majority.

At the same time, do you disagree with me that compared to voting by using marks, numbers, or rankings; grading candidates allows voters more meaningfully and informatively to express their qualitative judgments about the candidates?

I look forward to our next dialogue.
Steve

________________________________
From: Forest Simmons <forest.simmons21 at gmail.com>
Sent: Wednesday, October 6, 2021 7:38 PM
To: steve bosworth <stevebosworth at hotmail.com>
Cc: EM <Election-methods at lists.electorama.com>
Subject: Deterministic Epsilon Consensus Idea stimulated by a question of Steve Bosworth (was Election-Methods Digest, Vol 207, Issue 9)

Steve's query about Chiastic Approval included the following ....

 Also, correct me if I'm mistaken that XA does not guarantee that its winner will be elected with the support of a majority of all the votes (ballots) cast.

The short answer is "no" ...  no method can guarantee majority voter support for its winner, unless they can guarantee that at least one candidate is ranked, rated, scored, or graded above bottom on more than half of the ballots submitted.

The long answer is, "Why stop at half or two-thirds, as some methods require ... why not go for full 100% consensus?"

But, you may object, full consensus is not always possible. Well, neither is forty percent support always possible, but that doesn't stop the Constitution from requiring two-thirds of the voters' support for certain kinds of amendments, etc.

One expedient that has been suggested is the NOTA option for the case when the quota is not met.  This option gives new meaning to the word "approval" ... as Mike Ossipoff used to say, you approve a candidate if you would rather see her elected than have to come back next month to vote for someone else.

I would like to suggest another option based on the standard MJ grade ballot ...

Each candidate X gets a score that is given by the sum ..

S(X) = Sum (over j from zero to five) of the product

a(j)*epsilon^j,

where epsilon is a value to be determined by the voters ... and the respective values of a(j), for j in {0, 1, 2, 3, 4} are the number of ballots on which candidate X is graded strictly above reject, poor, acceptable, good, or very good, respectively.

Also each voter has the option of voting for a value of epsilon in the set {.01, .02, ... .99, 1.00}. The median of the distribution of these votes determines the value of epsilon.

Elect the candidate X with the max value of S(X) (once the epsilon value has been determined).

Note that if, for some j, the coefficient a(j) is the total number of ballots, then we can say candidate X is a full consensus candidate at level j.

If there are several full consensus level j candidates, then the higher degree terms will determine the winner.

Thanks!

FWS


FROM: Steve
TO: Forest
Re: Majority Judgment

Thank you for telling me about  Andy Jennings' "Chiastic Approval  (XA)".

However, please explain why do you say it is a "drawback" for MJ initionally to have a large number of "ties". You say this even when you also correctly say that the next steps in MJ count rationally and "cleaverly ... resolve such ties". Do you agree with me that this has the majoritarian advantage of guaranteeing that the winner is supported by at least 50% plus 1 of all the votes cast, and is unique in both have the highest median grade and the largest number of grades equal to or above the value of this highest median grade?

Also, in what sense do you see XA as being "more robust" than MJ?

At the same time, unfortunately, XA seems to allow votes to be express merey by numbers. I understand MJ's use of word grades (Excellent,Very Good,... Reject) to be democratically superior because grades are more meaningfully and informatively expressive of the qualitative judgments that can be made by voters.

Also, correct me if I'm mistaken that XA does not guarantee that its winner will be elected with the support of a majority of all the votes (ballots) cast.

For the above reasons, I do not yet see why you said that: "The voter instructions and other features of the voter interface
environment for Jennings' method are identical to those of MJ." What do you think?

I look forward to our next dialogue.
Steve



Great questions and suggestion!

However, in some venues not every voter has the patience to grade
potentially dozens if not hundreds of candidates as in past California
governor recall elections which were plenty cumbersome with FPTP style
ballots (which should have been voted and tallied under Approval rules). In
that context many more voters will have enough patience to vote in the
final round.

In my opinion MJ is a great improvement on most Cardinal Ratings/Score
based methods, but the certainty of tied median grades is a drawback
despite its signature clever method for resolving such ties.

A closely related but more robust method invented by Andy Jennings makes
ties vanishingly rare while preserving all of the advantages of MJ
including use of familiar, easy to understand grade style ballots with
minimal strategic incentive for grade inflation/exaggeration.

The voter instructions and other features of the voter interface
environment for Jennings' method are identical to those of MJ.

The method is called Chiastic Approval  (XA) because of an X shaped (i.e.
Chi shaped) graphical interpretation showing how MJ, Approval, and XA are
related to the candidates' grade distributions.

[Those distributions are discontinuous graphs that stair step down through
the six grade levels. A vertical line through the middle of such a graph
crosses at the midrange approval cutoff point between acceptable and poor.
An horizontal line through the middle of the graph crosses it at the median
... which illustrates the ambiguity of the median, since an horizontal line
will either miss the stair stepping graph entirely, or will intersect it
along an entire line segment. On the other hand, a diagonal line of unit
slope will cross the graph at precisely one point .. at the instant it
crosses from below to above the graph. The descending distribution graph
and the ascending diagonal line (segment) form the shape of the Greek
letter chi.]

It is pleasant for election geeks to contemplate such schematic diagrams,
but the beauty will be lost on anybody else ... best to save it for those
who might appreciate it :-)

The algebraic representation will be even more of an imposition ... best to
shred any  reference to it except as documentation of the software:

The distribution function F whose graph forms the descending staircase
alluded to above is defined as follows:

F(x) is the percentage of ballots that rate  candidate C greater than or
equal to x ... as x increases F(x) decreases.

So the chiastic approval of candidate C is the greatest value of x such
F(x) is no greater than x.

Putting it all together we have ...

The chiastic approval for candidate C is the greatest value of x such that
x is less than or equal to the percentage of ballots that rate (i.e. grade)
candidate C at or above x.

I warned you!

How many of you understand the Huntingto-Hill method of apportionment? Yet
that is the official method for determining how many representatives each
state gets in Congress and the Electoral College. And people trust in it
unquestioningly just as they implicitly trust the medical pharmaceutical
complex.

Chiastic Approval is arguably easier to explain than MJ except perhaps at a
superficial level that avoids the tie breaking details of MJ.

Once you understand the beauty and efficiency of both Chiastic Approval and
Approval Sorted Margins it becomes apparent that no Condorcet compliant
deterministic social order (single winner order of finish) can surpass
XASM,  Chiastic Approval Sorted Margins, IMHO:-)

Forest
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