Posts made by masiarek

@toby-pereira is it OK to mention your names at: https://github.com/masiarek/star-voting-library/blob/master/00_start_here/topics/condorcet/ordered_majority_rule_irv.md

Bummer - there are no perfect voting methods

Ballots:
       A,B,C
       1,4,3
       2,3,1
       5,0,4

Winner
  STAR      = A
  RCV-IRV   = B   (differs from STAR)
  Approval  = B   (differs from STAR)
  Condorcet = B   (differs from STAR)

Is this a good commentary:
https://docs.google.com/document/d/1DVhn9sbPpbXJCjN1fgFZzyKSfFbt97ksXWlh9K1wlOU/edit?tab=t.0

On a different note - it is probably impossible to come up with a contrived example where each method has a different winner - right?

We need three small, illustrative elections to demonstrate each ‘problematic’ box separately (avoid ‘Less Problematic’ Exhausted Ballots).

Assumptions:

• ranking limit 3 (or 5 if easier to re-create)
• number of candidates 5 (or less if easier)
• all voters correctly rank all the ballots (no spoilers, no bullet voting)
• all voters rank all ranks within Ranking Limit (3 or 5)

Context:

• article https://docs.google.com/document/d/1ASC5BS10rCfAYZWGeCyS7dKdKc4p5wwI6DHs4F7ScGc/edit

• presentation https://docs.google.com/presentation/d/1ipof9WSSy0GenVKWfKLu_jlYwUIT0TU0WVSAap0VZ5Q/edit#slide=id.g27f6bb33467_0_1

Comments, feedback - very much appreciated!

Book Chaotic Elections - Saari, page 34:

Strange Plurality voting notation:
A > C > B supported by a 5 : 4 : 2 tally.

Have you seen it somewhere?

Additionally, it is strange to see 'ranks' for plurality voting results/winners (instead of 'chose-one').

8:Ava>Cedric>Deegan>Bianca>Eli
6:Ava=Bianca=Cedric>Eli>Deegan
6:Eli>Ava>Bianca=Cedric=Deegan
6:Deegan>Bianca=Cedric>Eli>Ava
4:Bianca>Ava>Eli>Deegan>Cedric
3:Eli>Deegan>Bianca=Cedric>Ava
2:Deegan=Eli>Bianca=Cedric>Ava

1. preference matrix at https://electowiki.org/wiki/Ranked_Robin:
   

2. preference matrix at - https://www.cs.angelo.edu/~rlegrand/rbvote/calc.html
   

Youtube Video – [02:50..]

Ranks
G,B,P,R,O
18:1,5,4,2,3
12:5,1,4,3,2
10:5,2,1,4,3
9: 5,4,2,1,3
4: 5,2,4,3,1
2: 5,4,2,3,1

Ranks converted into Scores
G,B,P,R,O
18:5,1,2,4,3
12:1,5,2,3,4
10:1,4,5,2,3
9: 1,2,4,5,3
4: 1,4,2,3,5
2: 1,2,4,3,5

Voting Method and Winner
Plurality - Green
Two-Round Runoff- Blue
RCV IRV - Purple
Borda - Red
Range - Red
Approval - Red
Condorcet - Orange
STAR Voting - Orange

Here are my calculations: https://docs.google.com/document/d/1icQZ1efJV4XX7fD0_OTjNnW7uhfFV4lxbz5afTmqcyg/edit

ordered majority rule - Condorcet, IIA, monotonicity-not desirable properties ?!

A Majority Rule Philosophy for Instant Runoff Voting
https://arxiv.org/abs/2308.08430

Conclusions
IRV is the only voting method to satisfy ordered majority rule, which ensures the election of a candidate from the majority coalition while preventing opposition voters from influencing the choice of candidate from the faction they oppose. Ordered majority rule determines the relative social order between any two candidates by counting only ballots from those voters who do not prefer another major candidate, while ignoring all minor candidates.
Ordered majority rule is incompatible with the Condorcet criterion and independence of irrelevant alternatives because Condorcet and IIA demand that the relative social ranking between two candidates should depend on the relative social ranking of these candidates on all ballots. In addition, it is incompatible with monotonicity because monotonicity demands that if supporters of minor candidates have influence over lower ranked candidates, then supporters of major candidates should have equal or greater influence, while IRV does not grant influence over the social ranking of two candidates by voters who prefer a different major candidate. For situations where allowing supporters of a major candidate to have influence over the relative social ranking between other major candidates is deemed inappropriate, compliance with Condorcet, independence of irrelevant alternatives, and monotonicity are not desirable properties of a voting system.

My main objection - loss of expressive ballot.

Plurality voting is among the least expressive voting methods there is available.

2CV method seems to force voter to express opinion on two candidates only (lost expressiveness of the voting ballot).

You may very well have opinions about some or all of the candidates on a ballot, and yet you only get a say about two candidates only.

Other voting methods allow you to express yourself in different kinds of ways — for example:

• approval voting allows voters to choose any number of candidates;
• RCV lets you rank candidates by preference;
• score or range voting asks voters to give each candidate a score, with the winner being determined by the candidate with the highest total or average score.
• STAR Voting - multiple candidates - both score and preference !

Both STAR and RCV can fail to chose CW (Condorcet Winner).

How often does this happen?
Do we have any GitHub simulation software to flash it out (ideally with few example ballots).

Not sure what it is - but I never heard this term before - hence posting it here:

https://stablevoting.org

https://github.com/voting-tools/stablevoting-backend

Is this factually correct - any comments, ideas?https://www.rankthevoteohio.org/rcv_is_not_a_condorcet_system

Are these the best explanations? Anything else worth reading?
https://www.starvoting.org/pass_fail
https://electionscience.org/library/later-no-harm-criterion/
https://en.wikipedia.org/wiki/Later-no-harm_criterion
https://www.rangevoting.org/LNH.html

   A,B,C,D,E
8: 3,0,1,1,1
5: 0,4,0,0,0
2: 0,1,3,2,1
1: 0,2,5,4,3

Who is the Condorcet Looser (CL) and Condorect Winner (CW)?
How to build the Preference Matrix (find CW and CL) - Pairwise comparison.

Assume that election officials tossed a coin ahead of time - and the following Candidates were selected as tie breakers:

1. A
2. B
3. C
4. D
5. E

Tiebreaker candidates are selected from the above list, preferring candidates with lower numbers.

We have 4 seats to win (with 5 candidates) - who should win this election?

I would like to teak an existing Python RCV tabulation program to mark all the rankings (see below in red color) that have been ignored by RCV tabulation process (these are exhausted ballots). I want to be able to demonstrate to RCV folks how quickly and many exhausted ballots/rankings are ignored / discarded.

how to find programmatically:
https://www.rangevoting.org/IrvIgnoreExample.html - "the red parts of each ballot are ignored by the IRV process -

What would be the best algorithm to find the red parts?

@toby-pereira Is there a difference in an approach between Scoring (Cardinal/Rating) and Rankings (Ordinal) with equal ranks ?

Obviously the direction must be flipped

• score - high numbers (4,5) - winners,
• rankings - low numbers winners (1,2,3)

How to learn this lingo:

Pairwise Matrix
Pairwise preference
Pairwise preference - Strength of preference and rated pairwise preference ballot.
Ranked Pairs
Score Sorted Margins
Smith set vs Copeland set vs Schwartz set
Approval Sorted Margins
Pairwise Winner
Ranked Winners
Condorcet Winner (CW) / Loser (CL) / Improved Condorcet winner / Weak Condorcet loser
Improved Condorcet winner
Smith set vs Copeland set
Cardinal pairwise, cardinal-weighted pairwise (CWP) comparison

https://www.equal.vote/fv

FairVote voting methods comparison: RCV, Approval, STAR, Range, Condorcet - thoughts, comments?

https://fairvote.org/resources/electoral-systems/comparing-voting-methods/#criteria-resistant-to-strategic-voting

https://fairvote.org/resources/electoral-systems/comparing-voting-methods/#criteria-resistance-to-spoilers

https://www.equal.vote/ranked_robin (the first bullet point related to Ranked Robin Disadvantages)

A ranked ballot doesn't allow voters to express their level of support; a 2nd choice ranking could be almost as good as a voter’s favorite or almost as bad as their last choice. This also makes it less straight-forward to look at the election results see how much support a candidate had overall, especially compared to methods like STAR Voting and Approval Voting.

I do not understand this part "A ranked ballot doesn't allow voters to express their level of support"

On the same page - Ranked Robin Advantages:
Expressive. Allowing voters to give equal rankings helps voters express a more nuanced opinion and reduces cognitive load compared to Ranked Choice Voting. Additionally, voters will still be able to assign a rank to every candidate even if there are more candidates than available ranks on the ballot.

My Question: is Ranked Robin expressive or not? I assume that Ranked Robin is as expressive as STAR. What am I missing?

Is this correct: https://docs.google.com/document/d/1rZwCTlwZH4hA4PbWIDvJqXWSzutvVXrdC7VL3lnI6wM/edit

I am looking for a numerical example where STAR voting fails Condorcet Winner criterion.