[EM] [CES #4445] Re: Looking at Condorcet

[Jameson Quinn]

2012/2/6 robert bristow-johnson <rbj at audioimagination.com>

> responding to both Andy and Kristofer...
>
> On 2/6/12 2:31 PM, Andy Jennings wrote:
>
>  On Sat, Feb 4, 2012 at 10:01 PM, robert bristow-johnson <
>> rbj at audioimagination.com <mailto:rbj at audioimagination.**com<rbj at audioimagination.com>>>
>> wrote:
>>
>>    i really don't want this question distracted too much with "the
>>    guys and i are going out for pizza."  a little bit of distraction
>>    was okay, but the give-and-take relationship with my
>>    pizza-and-beer buds is just not the same as in a partisan contest
>>    that i bring my mace and shield.
>>
>>
>> It was, admittedly, an extreme example.  But a hyper-bitter cutthroat
>> political contest is the other extreme.
>>
>
> but, even if they are not hyper-bitter, people do not like finding out
> after the election that the election method had an "anomalous result"
> (meaning that it elected the "wrong" candidate, in some sense of the word)
> and, from a more objective POV, the election punished their honest vote or
> would have rewarded a tactical vote by sufficient numbers.  it's just any
> old political contest that is really *contested*, not some cooperative
> organization where everyone is thoughtfully thinking about "what would be
> the best for everyone?"  if the community gets big enough and the stakes
> get high enough (but not yet cutthroat), no one wants to experience that.
>


Say people vote rated ballots with 6 levels, and after the election you see
a histogram of candidate X and Y that looks like this:

(better)
6:Y X
5:  Y  X
4:     YX
3:     XY
2:  X  Y
1:X Y
(worse)
N:123456789

That is, 3 people rated X as 6 and only one person rated them as 1, and
vice versa for Y.

X wins, right?

If it's Condorcet, not necessarily. This is consistent with a 14:12 victory
for Y over X.

If you present the pairwise total, it's "obvious" to people that Y should
win. If you present the histogram, it's at least as "obvious" to people
that X should win. If what people find obvious isn't even consistent (which
even just pairwise isn't, of course; that's why there is more than one
Condorcet system), then you can't elevate "obvious" to an unbreakable
principle.

this is the whole point of why i hang around this mailing list.  this is
> what i think election reform is good for and this is why i am nowhere close
> to convinced that either a traditional FPTP, nor Approval, nor Score voting
> cuts the mustard.


A lot of why I support MJ over Score is that I know there are people like
you who will never reconcile to Score.


>  all's the voter wants to do is vote for his/her favorite candidate
> without finding out later that this vote harmed his/her political
> interests.


This is something that SODA accomplishes significantly better than any
Condorcet system. Listen to yourself: "All's the voter wants to do is vote
for his/her favorite...".


>  in order to do that, you *have* to collect contingency vote information
> (the ranked ballot),


Counterexample: SODA.


> but you need not add the additional burden to the voter as to how high
> they should rate their 2nd choice so as not to harm their 1st choice and
> not to help their last choice.  and, for Approval, it's the same problem
> because the voter has to decide whether or not to approve of their 2nd
> choice.  and we all know the problem with the traditional ballot with 3 or
> more candidates.
>
>
>   There are shades of gray in between and there are many elections that
>> fall nearer the pizza example than the mace and shield one.
>>
>
> it has to be a small and fairly homogeneous community.  and i think
> eventually someone is going to feel their political interests are getting
> short shriff and the time of "playing nice" has past.  then the elections
> become contentious and competitive and then i just don't see any good to
> asking voters to voluntarily dilute their "one person, one vote" from what
> they are allocated as one person.


You're not asking anybody to do anything. You're giving them the chance to
volunteer. Even if a small minority take that chance, it would be just as
unfair to that minority to force them to do otherwise, as it would be to
force the majority to dilute their vote unwillingly.

Note also that the cases where strategy is applicable in MJ are
*precisely*the cases where you might be inclined not to use strategy,
because you
consider the two frontrunners to be both good or both bad.


>  and with the additional burden of tactical voting (what to do about your
> 2nd choice) that makes either the Approval or Score ballot undesirable in a
> governmental election.
>

It's not a score ballot, it's a rated ballot. Because it can be used for
MJ, or indeed for Condorcet if you prefer, not just for score.

Jameson


>
> On 2/5/12 5:07 PM, Kristofer Munsterhjelm wrote:
>
>> ...
>>
>>  that is not well defined. given Abd's example:
>>>
>>>  2: Pepperoni (0.61), Cheese (0.5), Mushroom (0.4)
>>>> 1: Cheese (0.8), Mushroom (0.7), Pepperoni (0)
>>>>
>>>
>>> who says that for that 1 voter that the utility of Cheese is 0.8?
>>>
>>
>> The voter does. In this thought experiment, one simply assumes the
>> 1-voter's utility of Cheese is 0.8 so as to show the point. The point is
>> that there may be situations where utilitarian optimization and majority
>> rule differs.
>>
>>  how is that function defined in the "proof" that Clay repeatedly refers
>>> to
>>> where "it's a mathematically proven fact that Score does a better job
>>> picking the Condorcet winner than does Condorcet"?
>>>
>>
>> It isn't. Warren's argument that "Range is more Condorcet than Condorcet"
>> is quite different. I assume Clay is using that argument when he claims
>> "Range does a better job", but I don't know as I haven't seen Clay's
>> arguments.
>>
>> The first part of the argument is that, in the real world, people will
>> have access to polling data. Then, Warren argues, this means they will act
>> strategically.
>>
>
> They *may* anyway.  What evidence does Warren or anyone have that, given
> advanced polling data and knowledge that the election will be decided by
> Condorcet, that they will vote strategically in greater numbers, or that
> voters can expect to game the system anymore with Condorcet than they would
> with Score or Approval or FPTP or IRV?
>
> but we *know* what can happen with FPTP and IRV.  we've seen it.  we
> *know* that Approval and Score burdens voters with the question of what to
> do with their 2nd choice where the ranked ballot does not, in and of
> itself.  some methods of tabulating the ranked ballot *do* demonstrate and
> have demonstrated anomalies that can reward tactical voting.  but, whenever
> Condorcet is critiqued, it is with some pretty weird and contrived examples
> where voters do something *very* chancy, like burying their **2nd
> choice**!!  WHY would you *ever* want to take the chance and bury your 2nd
> choice if you are not assured your 1st choice will win???  even if you are
> confident your 1st choice will win, why bother to bury your 2nd choice?  so
> you guys have dreamed up weird and unlikely situations where some candidate
> in the "Radical Center" encourages his voters to bury the other centrist
> candidate who might also be the Condorcet winner.  but that's taking an
> awful big chance.  how are scenarios like this likely enough to trump the
> obvious reason for Condorcet which is to avoid a simple negative result:
> electing a candidate when more of us wanted another candidate to be elected.
>
> i don't get it.
>
>
>  Say that X is the honest Condorcet winner (and polls show that he is).
>> Then, according strategy, "anybody-but-X" people would rank X last.
>> Depending on the method and X's margin of victory, that could make some
>> other candidate win,
>>
>
> not with any confidence!  you might just blow it and hand the election to
> someone that everybody hates.  i just don't see that sorta nefarious voting
> strategy as having *any* appeal at all.  because of it's unlikelihood,
> because of the unlikelihood of a cycle, i just don't see what all this fuss
> is about.  i really don't see it likely at all that people will either try
> to game Condorcet nor will people need to revert to the tactic of
> "compromising" in Condorcet that we *know* they do in FPTP and that IRV
> encourages.
>
> ...
>
>
>  If you want to specify the proof further, you could say it really says
>> this: "if more than a certain fraction strategize in both the Condorcet
>> method and Range, if Condorcet strategy involves burying the sincere CW if
>> you prefer someone else, and Approval strategists know who the top-two are,
>> then Range elects the sincere CW more often than does the Condorcet method".
>>
>
> it's not proof!  it's based on the assumption that people *will* try to
> game Condorcet that way, even if it's Russian Roulette.  i don't get this
> argument at all.  again, we know how people are burdened by the
> compromising tactic with other systems, but this notion of nefarious
> tactics by people who twist their mustaches to get their favorite (whose
> otherwise a loser) to beat an honest CW is far fetched.
>
>
>  What if fewer people than that fraction strategize? Then Range will elect
>> the CW less often than the Condorcet method, but then Warren refers to
>> utilitarian reasoning and says: if people are mostly honest, then the
>> normalized Range values are based on their true utilities, and thus the
>> Range winner will have greater utility than the Condorcet winner, since the
>> Condorcet method knows nothing about utility.
>>
>
> Warren can say that, but saying it isn't proof.  who knows what people
> will do in the privacy of the voting booth?  is it *dishonest* (or
> compromising) to vote for one's 2nd choice over their 1st choice?  who
> really does employ burying and realistically expect to gain advantage by
> such?
>
>
>  so, i have a few questions for everyone here:
>>>
>>> 1. do we all agree that every voter's franchise is precisely equal?
>>>
>>
>> Yes.
>>
>>  2. if each voter's franchise is equal, should we expect any voter
>>> that has an opinion regarding the candidates/choices to
>>> voluntarily dilute the weight or effectiveness of their vote,
>>> even if their preference is weak?
>>>
>>
>> In a pizza scenario, voters might voluntarily dilute their weight to be
>> nice to the others. In a hotly contested governmental election, not as
>> likely.
>>
>>
> as i confirmed to Andy, it's governmental, it's competitive, and the
> stakes are high enough that no one wants to dilute their vote.
>
>
>  3. so, based on the answers to 1 and 2, if there is an election or
>>> choice between only two alternatives (yes/no) or two candidates,
>>> that this election be decided any differently than, as we
>>> were told in elementary school, the "simple majority" with
>>> "one person, one vote"?
>>>
>>
>> Those using utilitarian reasoning would say that if the prerequisites
>> hold (people know their utilities and they're commensurable), then a
>> utility-optimizing outcome is better than a majoritarian one.
>>
>
> remember, it's two-candidate or two-choice race.  so there is some
> utilitarian reasoning that accepts that all voters' franchises are equal
> and that no one wants to dilute their vote (because the outcome is
> important to the voter) and that this utilitarian reasoning conclude that
> awarding the election to the loser, the candidate or choice with the fewest
> votes, is optimum?
>
>  I think Warren uses a "tyranny of the majority" example in this case...
>>
>
> i remember last spring arguing with an anti-IRV Democrat that also apposes
> raising the 40% threshold to 50% (to preclude a runoff) that, with a
> straight face, tried to sell me this "tyranny of the majority" baloney for
> why we should elect a minority candidate and why there are instances where
> it's preferable to let the minority rule.  i think it was really bullshit.
>  this "tyranny of the majority" problem is either one about basic human
> rights that get codified in a "Charter of Rights and Freedoms" or something
> like that.  or it can be about putting a little bit of hysteresis in
> government decision making and requiring some super-majority to change
> certain policies.
>
> but the notion of "tyranny of the majority" is no reason that you award
> office to the loser in a two-candidate race.
>
>
>  One could of course argue that in cases like tyranny-of-the-majority, the
>> majority would just vote strategically to override the minority.
>>
>
> of course.  it's a trivial example of how anomalous or perverse election
> results will create an incentive to vote strategically.  if the loser wins,
> then vote for the candidate you don't like and your favorite will be the
> loser and gain office.  duh.
>
> then how does *anyone* claim that, given those conditions above
> (Two-choices, Governmental with reasonably high stakes, Competitive,
> Equality of franchise), that you decide the election any differently than
> the simple majority of equally-weighted votes?  i *still* don't get it.
>
>
> --
>
> r b-j                  rbj at audioimagination.com
>
> "Imagination is more important than knowledge."
>
>
>
> ----
> Election-Methods mailing list - see http://electorama.com/em for list info
>
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