[EM] Fw: (3) EPR, Bucklin STV, & Asset
steve bosworth
stevebosworth at hotmail.com
Mon Jul 23 17:28:19 PDT 2018
________________________________
From: steve bosworth <stevebosworth at hotmail.com>
Sent: Monday, July 23, 2018 11:02 PM
To: Kristofer Munsterhjelm
Subject: Re: (3) EPR, Bucklin STV, & Asset
________________________________
From: Kristofer Munsterhjelm <km_elmet at t-online.de>
Sent: Sunday, July 22, 2018 8:29 PM
To: steve bosworth; election-methods at lists.electorama.com
Subject: Re: EPR, Bucklin STV, & Asset
>From Steve:
Kristofer wrote:
>> K: On a side note, I think that redoing the method with a different initial
>> threshold is better than changing the initial threshold during the
>> process, as everybody gets to play according to the same rules. It is
>> also more complex, however.
>
> S: If your suggested ‘threshold’ would also limit the total number of
> weighted votes that a winner could retain, this would again needlessly waste some votes qualitatively. By contrast, the ‘the total number of voters/ number of seats’ threshold of EPR does not determine the upper limit of the number of weighted votes that can be retained by
> an elected candidate. This threshold only determines in what round all
> the next lower group of remaining evaluations must be added to the
> currently remaining higher evaluations in order to attempt to discover
> the next winner. EPR’s count treats all voters [and candidates] according to the same set
> of rules.
[….]
K: I'm not referring to a maximum limit on the weight of winners, but
rather to what happens in this step (quoting from jpolrisk):
> Round 7 searches for the 5th winner. However, one cannot be found even by Round 8 and even after > all the available ACCEPTABLEs have been added to the remaining
EXCELLENTs, VERY GOODs, and GOODs.
> No evaluations of POOR or REJECT must be added to help elect any candidate. Therefore, the
> remaining winners must instead be discovered by lowering the threshold of 10 iteratively by
> subtracting 1 (one-at-a-time) until the remaining winners are discovered.
K: What I'm saying is that a better approach is to consider that, whenever
you get to the sort of exhaustion that makes this lowering of the
threshold necessary, then instead of lowering the threshold (of 10) and
continuing the method, you should lower it and *restart* the method.
S: It may be true that some other *threshold* could be use initially and would still produce the same results. However, if it were too low, counting each of the rounds could be needlessly more complicated and less revealing, e.g. round 1 might discover a large number of tied candidates, some with the same large set of EXCELLENTS, VERY GOODS, GOODS, & ACCEPTABLES; and other with different mixtures of these. Because only one can be elected during any give round, discovering this one would probably require many more uses of lot, and/or of the SCORE calculations already illustrated by the explanation in the article of how the tie is broken in Round 6:
* i.e. in Round 6, G is discovered to have 10 affirmed evaluations and is elected. Still, this is the result only after breaking the tie between G, I, and J because each has received 10 evaluations at this stage. In this case, the tie does not have to be broken by lot because G’s 10 is composed of the set of highest evaluations. That G’s are highest is discovered by counting the EXCELLENTs, VERY GOODs, and GOODs that each had received instead as SCORES, i.e. as 6, 5, and 4. Consequently, each tied candidate’s total score at this stage is G-50, I-46, and J-44.*
If so, the lower the threshold*, the more EPR would become like a Bucklin-SCORE method. If so, this in turn would needlessly prompt more citizens to vote strategically, as well as dilute the greater clarity of meaning and discernment that is offered by EPR.
In any case, we must remember that EPR aims to guarantee that each winner will have been elected only because she has been awarded the highest set of evaluations currently available from citizens. If so, this means that round 1 must start by counting only all the EXCELLENTs given to all the candidates. If at least one of the candidates receives EXCELLENTs from at least 1/7 of all the voters in a 7 seat election, it seems correct that this candidate must be seen as elected, i.e. given EPR’s above stated aim.
K: The point is that the first few winners had a higher bar to clear (the
threshold of 10), while the latter winners had a lower bar (required by [the fact]
that no [additional] winners are able to clear the high bar that the threshold of 10
poses). So if the bar is to be lowered, it should be lowered
consistently for all candidates, not just for those who came in last.
S: [Please also consider the relevant earlier response.] In this context, the threshold is not a *bar* to be elected. It is only an intuitively acceptable guide to when the group of remaining next lower evaluations must be added in order to attempt to discover the next winner.
K: I'm thinking of a situation like: suppose the threshold is x voters.
Suppose there are a number of candidates who have EXCELLENT from x-1
voters each, but they don't get elected because the threshold is x. EPR
moves to the next round instead, and some candidates with X+1 number of [EXCELLENTs plus]
VERY GOODs get elected, …
S: In any case, only one of these candidates could be elected by this round. So, the tie between them must be broken. Such ties must be broken by lot unless one of these candidate’s x+1 evaluations is composed of higher evaluations as counted by the SCORE method as already illustrated above.
K : ….but it's not enough to fill s seats.
S: For your own above example, as I understand it, the rounds that would follow using the procedure suggested by my article would go on carefully and appropriately to discover all the remaining *seats* (winners).
K: After this point, the threshold gets lowered and some of the EXCELLENT candidates
get elected, filling out the council; but it would be more fair ….
S: If EPR allows each citizen to guarantee that her vote will proportionately add to the voting power of the winner she values most, how is this unfair?
K: …. to the voters if the count was restarted after the threshold is lowered, so
that all the X-1 EXCELLENT candidates get elected instead.
S: If I understand you correctly, only if each of your tied candidate’s sets of EXCELLENTs & VERY GOODs were entirely given to him or her by entirely different sets of citizens, would each of these tied candidates certainly be elected by either using my proposed procedures, or the ones you might have in mind. However, to the extent that these tied candidates shared some citizens’ evaluations, the total number affirmed evaluations currently retained by any given formerly tied candidate could change. These changes might still allow them to be elected after all the GOODs and/or ACCEPTABLEs had been added to the count, or they might not be elected at all.
What do you think? I very much appreciate your thinking this through with me. Again, I very much look forward to your feedback.
Steve
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