Posts made by Essenzia

@Keith said in S-TM:

If there was two candidates supported by the largest bloc of about 40% of the voters they would still fight with eachother.

Yes, but they would still both be supported by that 40% because they both don't want to do things that make them lose that block.
Positive the fact that they try to have the block bigger and bigger, but if the block is for example "Republican", it will remain "Republican" (as well as the 2 candidates who then end up in the automatic runoff).

Also, falling back to score is not something I would view as a problem

The problem is that if you end up in Score Voting then you might as well use Score Voting from the start, which is simpler (but has its downsides).

@multi_system_fan
Yes, there are unresolved tie cases as in any voting method. The important thing is that they are sufficiently rare.
If 1000 or more voters vote, it is extremely rare that multiple candidates have the same number of [best] or [worst] just as it is extremely rare in AV that multiple candidates have the same number of votes.
Frequent tie cases to be solved are those caused by condorcet cycles and for those the solution is proposed.

"The candidate with the highest sum of points wins" is not the method I am proposing. With a similar process, there could be many more min-max strategies.

@Keith
The benefits of STLR and STAR fall with the clones, becoming Score Voting. I don't think the added complexity of such methods is worth it in the long run (given that in the long run, political factions would understand this clone problem and exploit it to their advantage).

@Jack-Waugh
I have read KP and partly agree.
You look for a half way between IRV and AV.

S-TM instead is an half way to other methods:

• If everyone in S-TM voted with [worst] and [best], it would become AV.
• If everyone in S-TM voted with intermediate ratings, it would become Score.
• Condorcet (pairwise comparisons) to mix AV and Score.
• in case of tie, all candidates but 2 are eliminated on which the comparison is then made , similar to STAR.

@Jack-Waugh
Condorcet
Assuming to use tie procedure 2, the worst that can happen in the case of cycles is that some of the few candidates belonging to the cycle receive [worst] instead of intermediate ratings.
This is if the voter can predict that there will be a cycle and which candidates will belong to it (it's not easy).
If they don't know which candidates belong in the cycle, then minimizing is very risky because it also remains true that in case of not tie, minimizing to [worst] is senseless.

Tit-for-tat
Given these votes:
A [best] B [3] C [2] D [worst]
A [worst] B [2] C [3] D [best]
When it comes to the management of the tie (procedure 1), the 2 candidates with the most [best] are held, so A and C are in tie.
With tie procedure 2, the 2 candidates with least [worst] are held which are B and C, which however result in tie (if there was only B, I would have to keep B and one between A and C in tie).
You always end up with a tie (it makes sense), even if there is still an imbalance towards certain candidates (those with intermediate ratings) rather than towards others.
However, tit-for-tat is not a criterion that I value very much (and I also point out that it only fails in the case of tie, otherwise it's satisfied, unlike FPTP which always fails).

Score for tie
If I use Score, I introduce the min and max strategies in case of tie, while with my procedure only one of the 2 strategies can be valid in case of tie.

I will inquire about KP voting.

@Jack-Waugh
Yes, in practice, whoever is best able to predict the results, the best will be able to exploit this knowledge to his advantage... not to mention that the political factions could spread false information precisely to condition votes.

I prefer a voting system in which the voter's vote depends as little as possible on the background information (and as much as possible on his interests alone).

@Jack-Waugh
This is evidence:
if I want to maximize A (loved candidate), I vote:
A [5] BCDEF [0]
If I want to minimize F (hated candidate), I vote:
ABCDE [5] F [0]
If the voter wants to do both, then it is not clear what rating to give to the candidate BCDE.

This is a problem and it is not me who has to prove that in practice it does not show up (and possibly that it will not show up in subsequent elections).
However, I am collecting data on votes with ranges and what I notice for now is that it comes up quite often as a problem (at least, in online single winner polls). When I have enough data I will post about it.
I tell you that it also happens that some voters never give the score 0.

I have only stated that the S-TM is extremely resistant to a similar problem due to how the results are calculated (as well as the methods that use rank with one candidate per position).
I have made other small statements (even subjective), but the core of the speech does not change.

@Jack-Waugh
Yes, but it seems to me that they often just observe who the 2 frontrunners are and then give max (5) to the best of 2, and min (0) to the worst.

More generally, the min-max problem for range methods is quite recognized as such, and it is the reason why maybe someone prefers a ranking with a single candidate for each position (because in that, you certainly can't min-max) .

If I want to maximize A (loved candidate), I vote:
A [5] BCDEF [0]
If I want to minimize F (hated candidate), I vote:
ABCDE [5] F [0]
If the voter wants to do both, then he won't know what scores to give BCDE candidates. The fact that I have to use result predictions to decide what scores to give BCDE candidates seems very wrong to me.

S-TM tries to solve this problem with [worst] and [best] ratings which allow to maximize/minimize candidates A/F without imposing conditions on B, C, D, E for which the voter will be much more encouraged to give honest (intermediate) evaluations.

@Jack-Waugh
"Work better" in what sense?

If this is my honest vote in SV:
A [5] B [4] C [3] D [2] E [1] F [0]
and I want to maximize A and B's chances of winning (to the detriment of the others), then my vote will tend to go like this:
min: A [5] B [5] C [0] D [0] E [0] F [0]
If, on the other hand, I want to make sure as much as possible that E and F lose, then my vote will tend towards this:
max: A [5] B [5] C [5] D [5] E [0] F [0]

In methods such as STAR, on the other hand, it may make sense to also assign a rating of 1 (intermediate) to compromise candidates.
Better than SV, but the min-max problem is still there, also because the first step makes the two candidates win with the higher sum, so it's like SV (in fact, with clones, STAR becomes SV).

In S-TM (with tie procedure 1) maximizing makes no sense, while minimizing makes no sense except in the case of tie (very rarely).

@Jack-Waugh
Exactly like that.

I hypothesize that if a voter assigns [best] to a candidate, then he would definitely want the opponent to be at 0 points (respectively, if he assigns [worst] he wants the opponent to be at 5).
If he uses intermediate scores instead, he can agree to leave them as they are.

An STLR-style normalization could be done on the intermediate scores, eg: [1,2] becomes [2.5,5] but I think it would complicate the procedure too much.

@Jack-Waugh
Considering 2 candidates, the points they receive in the various votes are added and the one with the highest sum wins.
The [worst] and [best] ratings have special rules that describe how to treat them in the sum.

The candidate with the most wins in pairwise match wins (all pairwise matches are made).

@Jack-Waugh
thanks, I was wrong, I corrected!

Problem to face
In methods with range [0,5] there are almost always min-max strategies that force the voters to use only ratings 0 and 5, as in approval.
In the case of methods that eliminate and normalize (STAR, etc) 1 is also used.

• If the intermediate candidates are set to 0 it is to favor as much as possible the most appreciated candidates, who have 5.
• If intermediate candidates are put at 5 is to disadvantage hated candidates at most, who have 0.

S-TM Procedure
You vote in a range with these values: {worst,1,2,3,4,best}.
For each pair of candidates the best is found, by adding up the points (win the highest sum), with these rules:

• the candidate with [best] receives 5 points, and 0 points to the other.
• the candidate with [worst] receives 0 points, and 5 points to the other.
• if both have intermediate values, so they ​​are added as they are.
  (- a vote in which the two candidates have both [worst] or [best], is not added).

The candidate who wins in the most pairwise matches wins.

Tie

1. Only the 2 candidates (among those in tie) with the highest number of ratings [best] are considered, among which the one who won in the pairwise match wins.
   or
2. Only the 2 candidates (among those in tie) with the lowest number of ratings [worst] are considered, among which the one who won in the pairwise match wins.

Example (tie 1)
Given an honest vote like this:
A [best] B [4] C [3] D [2] E [1] F [worst]
A's probability of winning does not change if the vote were like this:
A [best] BCDEF [worst] (all at worst except A).
while, the probability of victory of candidate F [worst] would increase.
There is no point in minimizing it in that way.

Respectively, if the vote were tactically like this:
ABCDE [best] F [worst]
the probability of victory for F would not decrease (apart from the rare cases of ties), while the probability of victory for A would decrease compared to honest vote.
Maximization is extremely disadvantaged (it can only serve in rare cases of tie, and it can disadvantage the victory of the true best candidate).

Tie 2) Maximization could be more disadvantaged (slightly favoring minimization) using procedure 2 in tie cases.

Conclusion
Limiting ourselves to the case of min-max strategies, the voter after assigning [best] to the candidates that he loves the most, and [worst] to those he hates most, will be able to feel free to assign intermediate scores to the other candidates.

Extreme case:
The intermediate ratings are maximized, making the honest starting vote become:
A [best] B [4] C [4] D [1] E [1] F [worst]
However, min-max intermediate candidates remains less favorable than min-max on the classic other systems with range.
P.S.
Due to the meaning of [worst] and [best] (not numeric values), it's not possible to uniquely convert a vote with range [0,5] into an S-TM vote.
I think that ratings with range [0,7] would probably be converted like this:
{7,6,5,4,3,2,1,0} --> {best, 4,3,2,2,1, worst, worst}

@Keith
Given these 3 types of ratings (assuming they are the ratings of the 2 frontrunners, after eliminating all the others):
[0,1] - [2,3] - [4,5]
STLR normalizes them like this:
[0,5] - [3.33,5] - [4,5]
Baldwin normalizes them like this:
[0,5] - [0,5] - [0,5]

For me, STLR uses better normalization but I don't think it's the best.
If a vote like this: [4,5] remain the same in the clash between the two finalists, the voter from the start will be encouraged to downplay the rating of the worst candidate of the 2 (i.e., to vote like this from the start [0,5] ).
I prefer this normalization in clash between two finalists:

• if you have a couple [0,0] or [5,5] the vote is irrelevant.
• if one of the two candidates has a score of 5, the other is put at 0.
• if one of the two candidates has a score of 0, the other is put at 5.
• if both candidates have intermediate scores, then STLR normalization applies.

For simplicity, I call START the STAR that uses this normalization.
In this way, at the beginning the voter:

• first assigns 5 to his most favorite candidates and 0 to the most hated ones.
• then he can feel freer in assigning intermediate scores.

Such normalization is proposed indirectly in Tragni's method, although in that context it is used to make comparisons between couples.

IRV uses ranking which is inconvenient as a voting method.
Ranking requires (for "voter equality") that all voters evaluate the same number of candidates and therefore there will always be some voters who wanted to rank more candidates, and other voters who wanted to rank less.
Writing it on paper is more difficult than AV.

AV, on the other hand, is exaggeratedly simple to understand and write, with no restrictions on the minimum or maximum number of candidates to be evaluated.

On a theoretical level, IRV doesn't seem to me to have good enough sides to beat AV.

@Jack-Waugh
Defect SV
Voting without strategies, range [0,9]:
A[9] B[3] C[0]
The voter thinks that B and C are the 2 frontrunners, therefore:
SV: A[9] B[9] C[0]
Whether with the min-max strategy, or without, the voter wants his vote to be worth the maximum in the clash between B and C (certainly not B[1] C[0]).
STAR: A[9] B[3] C[0]
In the clash between only B and C, the vote would automatically become B[9] C[0], so the voter does not need to lie at the beginning.
If he uses min-max the vote becomes:
A[9] B[1] C[0] which is still better than SV.

STAR majoritarian
Votes without strategy like this:
55%: A[9] B[8] C[0]
45%: A[0] B[8] C[9]
STAR wins A while SV wins B, with almost double the points of A.
In a strategic min-max context (and forecast on frontrunners) the votes would become as follows:
55%: A[9] B[0] C[0]
45%: A[0] B[0] C[9]
and A would also win in SV.
The point is that we should make B win as much as possible in a similar context and with STAR, B certainly never wins (strategies or not).
The practical example would actually be:
55%: A > B
45%: A < B
with A and B finalists. The individual ratings of A and B can change but in the majority methods, A always wins, while in the utilitarian ones, B can win when it has greater utility.

Other methods such as STLR and DV avoid the SV defect, without however being majoritarian like STAR. However, they can have other flaws (es. STLR can lose its positive sides in the presence of clones making STAR a better alternative for semplicity, DV fails monotony).