Re: [EM] RE : Ranked Preference benefits
Juho,
Juho wrote:
On Nov 2, 2006, at 1:29 , Kevin Venzke wrote:
Juho,
--- Juho [EMAIL PROTECTED] a crit :
Example 1. Large party voters consider C better than the other large
party candidate, but not much.
45: LCR
40: RCL
15: CL=R
Ranked Preferences elects L. (first round: L=-10, C=-70, R=-20;
second round: L=-10, R=-20)
In my opinion, if C is able to convince *every voter* to acknowledge
that he is better than the major party alternative, then C is surely
not a bad result.
There is no need to convince every voter. This example is simplified
(for readability) but not extreme since there could well be a mixture
of different kind of votes. (See e.g. example 4.)
The utility of C could be really low to the voters even though it was
ranked higher than the worst candidate (in Range terms e.g. R=99,
C=1, L=0). One of the key points of Ranked Preferences is that also
weak preferences can be expressed and they may have impact.
CB: So in your example is electing C a "bad result" or not?!
As long as truncation is allowed, and voters have the opportunity to
learn how the method works, I don't think "weak" CWs would be a real
problem.
I take this to mean support to basic (flat preference) Condorcet
methods with active use of truncation.
If they're not "good enough" to win at all, people should not
be giving them votes.
I'd prefer methods where voters can simply vote sincerely without
considering when it is beneficial to truncate and when not.
Yes, don't we all. You like methods that meet Later-no-Harm and
Later-no-Help, so how
then is your method supposed to be better than IRV?
Condorcet
voters need not leave non-approved candidates unlisted. I think
Ranked Preferences provides some improvements. I'll try to explain.
If A and B voters would all truncate we would end up in bullet voting
and falling to a plurality style election. Not a good end result.
45: LC=R
40: RC=L
15: CL=R
Since it gives the same winner as your suggested method, why not?
I think it is a problem of basic Condorcet methods that they easily
elect the centrist candidate.
No, that is their theoretical strength. One big (over-looked by you)
reason why the "weak,
low-SU, centrist CW" is mostly a non-issue is that Condorcet methods
create strong incentive
for "strong" high-SU centrists to be nominated. This idea is well
explained in James Green-Armytage's
July 2003 essay/post "the responsiveness of Condorcet".
http://lists.electorama.com/pipermail/election-methods-electorama.com/2003-July/010083.html
If preference strengths are not known
electing the Condorcet winner is a good choice (and basic Condorcet
methods are good methods). If preference strengths are known, then
the choice is not that obvious. Ranked Preferences takes into account
the relative strength of preferences (but not the "absolute
strengths" in the Range style). The end result is more expressive
than basic Condorcet but still quite immune to strategies (?).
The "end result" is a horribly complicated, very awkward- to-operate
monstrosity that we know
fails both Condorcet and *Majority Loser* ( but you hope is "quite
immune to strategies".)
I am a great fan of "Definite Majority Choice" (DMC).
http://wiki.electorama.com/wiki/DMC
But suppose I was on the "same page" as you and thought that if the CW
is a "weak low-SU
centrist" then it is desirable to elect a "higher-SU" candidate, and
also that the "ranked preference"
style of ballot you suggest should be used. In that (hypothetical)
case I suggest:
"Interpreting ballots as approving all candidates above the strongest
indicated preference gap ("ties"
resolved by approving as many as possible without approving any ranked
bottom or equal-bottom)
calculate the Definite Majority set (i.e candidates not pairwise beaten
by a more approved candidate).
If that set contains one candidate X only, elect X.
If not eliminate (drop from the ballots and henceforth ignore) the
candidate with the fewest top (among
remaining candidates) preferences.
(I prefer above bottom equal-ranking to be not allowed, but if it is,
then "fractional").
Recalculate (among remaining candidates) the DM set and repeat the
whole process until an X is elected."
That at least meets Majority Loser and is relatively easy to operate.
Also in common with IRV it meets
Dominant Mutual Third, Majority for Solid Coalitions and Condorcet
Loser.
45: LCR
20: CRL
35: RCL
In this example you give your method electing L, failing Majority
Loser.
My suggested alternative (first) interprets the 45 LCR as
LCR and so calculates the initial DM set
as {C} and so elects C. If instead the votes were
45: LCR
20: CRL
35: RCL
then all the candidates are in the initial DM set, so C is eliminated and then
the "new DM set" is {R} so R wins.
Example 4. Some of the large party voters think C is good
[EM] RE : Ranked Preference benefits
I am reposting this from my post at the rangevoting list (slightly modified). http://rangevoting.org/PropRep.html "You want to get both best possible quality accountability and best possible representation" This is an interesting point. What about an assembly elected as follows: The country is split into 3*N districts and the districts are grouped into groups of 15 districts. Each district elects 1 representative using approval with a reasonable one seat system. The groups then each elect 5 candidates from 15 first round winners using PR-STV or some other PR system where the voters get to pick who gets elected. In theory, both ballots could be cast at the same time. However, having to rank all candidates for 15 districts might be pushing it a little. This headache could be lessened by allowing voters to vote for their favorite candidates and then vote for party. (the party would only matter if the vote has to transfer past the candidate listed on the ballot). Another option would be that they could vote by district for the later options. Step 1 results in higher quality candidates and step 2 results in proportionality in representation. In fact, maybe there could be a "Winner's and a Loser's House" (though you probably wouldn't want to call them that :) ). Alternatively, after the PR-STV step, the 2 condorcet winners of the remaining candidates could be elected to the upper house. Obviously, whichever house is more powerful would have to elect candidates first. This gets you a (sorta) PR based lower House and a single seat based lower House. One issue is that the resulting house would probably be slightly biased to the districts that elected its members. OTOH, this creates an incentive for districts to pick a "good" candidate ... though that might take things back to the 2 party system (as the best way to get your candidate elected is to pick one from a reliable party ... though with PR that just means pick a party that will likely get 1 person elected). Another way of looking at it is that ballot access is based on the first stage election. This could be taken to extreme and completely decoupling the 2 elections. There could be regular "ballot access" elections and only people who have won at least one ballot access election are allowed to stand for office. However, the election for office itself would be PR based. The ballot access election districts might cover 10% of the country. In the US, they could even be the States. Raphfrk Interesting site "what if anyone could modify the laws" www.wikocracy.com Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading spam and email virus protection. election-methods mailing list - see http://electorama.com/em for list info
[EM] using single seat elections as a first stage for a PR election
Sorry about re-sending this. I forgot to change the title, and this post has nothing to do with the previous title. http://rangevoting.org/PropRep.html "You want to get both best possible quality accountability and best possible representation" This is an interesting point. What about an assembly elected as follows: The country is split into 3*N districts and the districts are grouped into groups of 15 districts. Each district elects 1 representative using approval with a reasonable one seat system. The groups then each elect 5 candidates from 15 first round winners using PR-STV or some other PR system where the voters get to pick who gets elected. In theory, both ballots could be cast at the same time. However, having to rank all candidates for 15 districts might be pushing it a little. This headache could be lessened by allowing voters to vote for their favorite candidates and then vote for party. (the party would only matter if the vote has to transfer past the candidate listed on the ballot). Another option would be that they could vote by district for the later options. Step 1 results in higher quality candidates and step 2 results in proportionality in representation. In fact, maybe there could be a "Winner's and a Loser's House" (though you probably wouldn't want to call them that :) ). Alternatively, after the PR-STV step, the 2 condorcet winners of the remaining candidates could be elected to the upper house. Obviously, whichever house is more powerful would have to elect candidates first. This gets you a (sorta) PR based lower House and a single seat based lower House. One issue is that the resulting house would probably be slightly biased to the districts that elected its members. OTOH, this creates an incentive for districts to pick a "good" candidate ... though that might take things back to the 2 party system (as the best way to get your candidate elected is to pick one from a reliable party ... though with PR that just means pick a party that will likely get 1 person elected). Another way of looking at it is that ballot access is based on the first stage election. This could be taken to extreme and completely decoupling the 2 elections. There could be regular "ballot access" elections and only people who have won at least one ballot access election are allowed to stand for office. However, the election for office itself would be PR based. The ballot access election districts might cover 10% of the country. In the US, they could even be the States. Raphfrk Interesting site "what if anyone could modify the laws" www.wikocracy.com Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading spam and email virus protection. election-methods mailing list - see http://electorama.com/em for list info
Re: [EM] RE : Ranked Preference benefits
Juho, You mentioned strongest indicated preference gap as the approval cut. How about defining it dynamically so that one would find the strongest preference relation that still has non-eliminated candidates at both sides of it? (like in RP) CB: I did. Or if I didn't make it clear, I meant to. Otherwise there wouldn't be any point to the lower ranked preference gaps. Interpreting ballots as approving all candidates above the strongest indicated preference gap... Recalculate (among remaining candidates) the DM set and repeat the whole process until an X is elected. When we repeat the whole process, strongest indicated preference gap refers to preference gap among remaining candidates. BTW, the initials RP are well taken by Ranked Pairs so if your method is going to stick around maybe it should have a different name. The name ranked preferences seems to just refer to the ballot style, which has been previously on EM called a dyadic ballot. Chris Benham Juho wrote: On Nov 3, 2006, at 19:50 , Chris Benham wrote: Juho wrote: On Nov 2, 2006, at 1:29 , Kevin Venzke wrote: Juho, --- Juho [EMAIL PROTECTED] a écrit : Example 1. Large party voters consider C better than the other large party candidate, but not much. 45: LCR 40: RCL 15: CL=R Ranked Preferences elects L. (first round: L=-10, C=-70, R=-20; second round: L=-10, R=-20) In my opinion, if C is able to convince *every voter* to acknowledge that he is better than the major party alternative, then C is surely not a bad result. There is no need to convince every voter. This example is simplified (for readability) but not extreme since there could well be a mixture of different kind of votes. (See e.g. example 4.) The utility of C could be really low to the voters even though it was ranked higher than the worst candidate (in Range terms e.g. R=99, C=1, L=0). One of the key points of Ranked Preferences is that also weak preferences can be expressed and they may have impact. CB: So in your example is electing C a bad result or not?! I'd say it would be a bad result. If we only knew the flat preferences then C would be a good choice (Condorcet winner). But when we know the preference strengths electing C doesn't look sensible. We may have different ways to estimate at which point C should not be elected. Range would give one style of measuring it. Ranked preferences gave another one which I think is quite natural. I'd prefer methods where voters can simply vote sincerely without considering when it is beneficial to truncate and when not. Yes, don't we all. You like methods that meet Later-no-Harm and Later-no-Help, so how then is your method supposed to be better than IRV? This is a topic that I was planning to write more about. Ranked Preferences actually can support also IRV style voting in addition to Condorcet style flat preferences and many kind of more complex styles. IRV style ballots would look like ABCDE. If all voters vote this way the behaviour of the method resembles IRV. Voters are thus not forced to vote in IRV style but they can do so if they so want, possibly for defensive reasons (later-no-harm etc). The tied at bottom rule has also a similar defensive impact. I have no clear proofs (due to complexity and insufficient background work) but I believe the Ranked Preferences method quite well balanced e.g. in the sense that voting IRV style is not the only or recommended or optimal way to vote but just one of the alternatives, for voters that really feel that way. I hope the readers of this list will point out any potential weaknesses. I hope the method is better than IRV for the same reasons I believe it is (in some/many aspects) better than Condorcet. It is more expressive and therefore takes voter preferences better into account. Maybe without introducing too many weaknesses that would spoil the idea. Condorcet voters need not leave non-approved candidates unlisted. I think Ranked Preferences provides some improvements. I'll try to explain. If A and B voters would all truncate we would end up in bullet voting and falling to a plurality style election. Not a good end result. 45: LC=R 40: RC=L 15: CL=R Since it gives the same winner as your suggested method, why not? It gives the same winner in this particular case but not in general. And of course I try to make the method more expressive than Condorcet, not less expressive :-). (Range easily becomes Approval in competitive situations. I don't want Condorcet (or Ranked Preferences) to become Plurality.) I think it is a problem of basic Condorcet methods that they easily elect the centrist candidate. No, that is their theoretical strength. I agree that ability to elect centrist candidates is one of their strengths. I just want to add that centrist Condorcet winners are not always
