Margins, majority, strategy

[Mike Ositoff]

> 

Replying farther down in this letter:


> I am going to attempt to reply to some of the points Mike has made with
> regard to the Margins vs. Votes-Against issue.
> 
> First, I would like to admit that Votes-Against is indeed more
> truncation resistant.  In effect, it penalizes voters for insincerely
> leaving candidates unranked.  It also penalizes voters for sincerely
> leaving candidates unranked.  I think if you really think the harm of
> truncation is so great you have to penalize all voters who leave
> candidates unranked, it would be more honest to simply ban leaving
> candidates unranked, as the Australians do.
> 
> > > Votes-Against fails this criterion because if your sincere preference
> > > is A > B=C, it is more likely to your advantage to rate A > B > C or 
> > > A > C > B.  It can back-fire, but the insincere vote is more likely
> > > to get you what you want, so unless you have detailed knowledge about
> > > how everyone else is voting, the insincere vote is better.
> > But that isn't really what I'd call a serious strategy
> > dilemma. No one is being strategically forced to do other
> > than vote their favorite alone in 1st place.
> > 
> > I don't like it when people have to rank a less-liked alternative
> > equal to or over a more-liked one. But if I'm indifferent between
> > B & C, and if I estimate that I could benefit by ranking B over
> > C, then that doesn't bother me. If I'm indifferent between them
> > why should I care if I rank one over the other?
> 
> Well, I guess you could complain that you have been forced to waste your
> time unnecessarily filling out a ballot randomly.  However, I am more
> concerned with the people who do not random-fill than those who do. 
> 
> Their votes are not worth as much, for reasons almost everyone would
> call unfair.  In a sense, I am not so much concerned that people will be
> encouraged to random-fill as that many will choose not to.
> 
> > I don't know how meaningful it is to say that Margins
> > meets a Sincere Expression Criterion which Votes-Against
> > doesn't meet, when Margins requires, as defensive strategy,
> > the most extreme forms of insincere expression. And when
> > that isn't the case with Votes-Against.
> 
> Actually, its the Sincere EXPECTATION Criterion.  In short, it
> says that a sincere vote should be justified by its expected result,
> assuming no knowledge of how others are voting.  Of course, we know that
> if a voter knows how others are voting, strategy does play a role. 
> But should there be strategies even if you have no such knowledge?

There shouldn't, but it isn't a serious problem, compared to
the failures & violations permitted by Margins.
But of course what's important to you could easily, & not wrongly,
be different from what's important to me. So, to you, 
Margins' violations might be less serious. The issue of choosing
a rank-balloting count rule can be a hopeless mess when different
people want different things. I suggest that the extremelyk
simple Approval rule is the answer then. Sure, various types
of rank-count theorists will say that according to their
standards Approval isn't good enough. Sure, and neither are the
other rank-methods either. But Approval has something that none
of the rank-methods have: Simplicity, extreme ease of implementation,
and being nothing other than Plurality done right, rather than
a completely new method based on a controversial new theory.

done


> 
> When there are, it should force us to question whether our definition of
> a sincere vote matches our method of vote tabulation.  Why do we define
> voting
> 1. A
> 2. B C
> as a sincere vote for the opinion A > B = C, if either
> 1. A
> 2. B
> 3. C
> or
> 1. A
> 2. C
> 3. B
> will both on average get better results for this opinion?  There have to
> be some limits on our ability to arbitrarily define what constitutes a
> sincere vote.  Votes-Against and Approval are the only methods I know
> of with this problem.
> 
> > > I notice that when you say X has a majority over Y, you mean a majority
> > > of all voters, not just those expressing a preference between X and Y.
> > > So, it is in effect, a three way race between X, Y, and the abstainers.
> > > Some people might want to use the word majority to mean a majority of
> > > eligible voters, or of the population as a whole, etc.  I do not 
> > > consider any of these uses of "majority" necessarily right or wrong, but
> >
> > > I tend to use it to mean a majority of those expressing a preference
> > > between X and Y.
> > 
> 
> > In a multicandidate election, the universally-used meaning for
> > "majority" is more than half of all of the voters who particpated
> > in the election. You can use the word differently, and say
> > that Jones has a majority over Smith anytime Jones beats Smith
> > pairwise. But the word then has less meaning. And we already
> > have terminology for that meaning: pairwise defeat.
> 
> I wonder what you mean by "universally-used".  I suspect that many
> people will actually be confused by this use of "majority".  I know I
> was, when I first started reading this list.  Certainly all those MPV
> advocates who say that the winning candidate gets a majority in the
> final round are implicitly assuming my use of the word majority.  Not
> that MPV advocates are always right, but since there are so many of
> them, I would consider their opinion before considering something as
> universally accepted.  To me, it seems natural to view those people who
> do not express a preference between two candidates as not participating
> in the simulated vote between them.  So, a candidate can have a majority
> in the simulated vote just by beating the other side.
> 
> But of course, this is just a semantic argument.  The real argument is
> whether a pairwise victory where the winning side constitutes a majority
> of all voters should always take precedence over a pairwise victory
> where it does not.  I think it is a big stretch to believe that this is
> a direct result of the principle of Majority Rule, as you imply.
> 
> > A genuine majority has the power to get whatever its members
> > all want. They should be able to do so without insincere
> > voting. When they need insincere voting to get a result that
> > they all want, I call that "defensive strategy". The need for
> > extreme degrees of defensive strategy is very undesirable.
> > When it's necessary to insincerely rank a less-liked alternative
> > equal to or over a more-liked one I call that "drastic defensive
> > strategy". As I said, that's what we don't like about FPTP
> > (1-Vote-Plurality).
> > 
> > Obviously, when the more-liked of those 2 is your favorite,
> > that's even worse. And when it's necessary to rank a less-liked
> > alternative _over_ your favorite--can a method get any
> > worse than that?
> 
> According to Arrow's theorem, every ranked method has that property. 
> Perhaps I have not understood you correctly.  Are you assuming there is
> a Condorcet Winner?  Are you assuming middle voters do not use
> order-reversal?  You will have to state your implicit assumptions before
> I can respond to this.
> 
> > > However, I think we should consider that the same votes could result
> > > 44 A C B
> > > 28 B
> > > 28 C B A
> > > And that they are actually all sincere.  This results in
> > 
> > If they're all sincere, there's no Condorcet winner to protect.
> > And it isn't possible to avoid violating the expressed wishes
> > of a majority. That isn't the kind of situation where there's
> > a LO2E problem, where it's necessary & possible to avoid 
> > serious violations.
> 
> I think this may be our main difference of opinion.  You are only
> interested in situations where there is a Condorcet winner.  I think it
> is important to use a method that is fair and reasonable even when there
> is no Condorcet winner.  A fair method would not punish voters for
> ignorance of the random-filling strategy.  A reasonable method would not
> consider a vote of 
> 	52 to 48
> as more decisive than a vote of
> 	51 to 1
> 
> We should remember why we abandoned GMC in its original form.  To do so
> meant we had to abandon some of the stronger statements about the power
> of a "genuine" majority.  And the difference between original and beat
> path GMC only affected those cases without a Condorcet winner.  But we
> abandoned it anyway because of the strange way it forced a method to
> behave in these cases.  I think the next step is to abandon GMC and the
> genuine majority distinction altogether for the strange results it
> causes.
> 
> I imagine someone could at this point say, "All right, it does not make
> any sense to sincerely leave candidates unranked in Votes-Against, but
> that is a small price to pay for the defensive strategy it creates for a
> Condorcet winner against order reversal.  That is, the purpose of
> leaving candidates unranked should not be because you consider these
> candidates equal, it is because your favorite is a Condorcet winner and
> you want to try to protect against order-reversal."
> 
> Presumably, the introduction of the Votes-Against method would go
> along with a public education campaign.  The campaign would explain how
> leaving candidates unranked is not intended for cases where you think
> they are equal and lower.  It would be explained that this is instead
> intended to be used by voters if they are sure there candidate is a
> Condorcet winner, and want to defend against possible order-reversal.
> 
> > Blake said that in Votes-Against, everyone would start
> > ranking everyone, even if indifferent between them, and then
> > the method would become equivalent to Margins, except for
> > offensive strategies. Big difference.
> > 
> > Say everyone starts ranking everyone, even without having
> > a preference between them, and that, as Blake suggests, that
> > will lead to order-reversal the way marijuana leads to heroin.
> > 
> > But what's the Votes-Against defense against order-reversal?
> > Strategic truncation. Avoid ranking more candidates than you
> > estimate necessary. Oh what a cruel dilemma that puts the
> > strategists in! They can't resist ranking everyone,even though
> > they know that it sets them up for the order-reversal that
> > everyone has been led to because of discovering the benefits
> > of ranking everyone.
> 
> I would like to deal with the contradiction between the statements
> 
> 1.  You should always random-fill instead of truncation
> 2.  Truncation defends against order reversal
> 
> The problem is that although the random-fill strategy is best if what
> you care most about is getting your candidate elected, truncation can be
> used as a way to punish people who insincerely vote against you.  That
> is, given voters who vote X first, and then are evenly split between
> voting Y and Z second, truncation will never help X win.  It will make X
> more likely to lose.  It does not defend in the sense of protecting X,
> and for this reason I am doubtful of whether people could be convinced
> to use it.  However, it does mean that the election will tend to be won
> by whichever of Y and Z, has voters who sincerely or insincerely rate X
> the highest.
> 
> > But wait, it gets better than that: In VA, the defensive strategy
> > punishes, & deters the order-reversal, while, in Margins, the
> > more effective your defensive strategy, as a C voter in my
> > example, the _safer_ you make the order-reversal. You make
> > it safer if you vote B equal to C. You make it completely safe
> > if you vote B over C. When order-reversal is less risky, it
> > will be more tempting.
> 
> I doubt whether order-reversal will really be less risky.
> 
> > In a public election, if you organized the B voters to
> > vote C in 2nd place, whether sincerely or not, do you think
> > that the C voters wouldn't hear about that? You'd be setting
> > B up for offensive strategy by C voters. And with Margins,
> > it wouldn't even take order-reversal. Mere truncation would
> > often do the job.
> 
> I do not think you can criticize a method for both being more safe for
> the initial reversers and more likely to give the election away to the
> other side.
> 
> > Look what you're saying the B voters would have to do to defend
> > against order-reversal. The defense that they have in Margins
> > is just the general pairwise defensive strategy. Whereas in
> > Votes-Against, they can defeat the truncation by merely not
> > voting for A or B, in Margins they have to vote the other
> > extreme over the extreme whose voters they expect to use
> > order-reversal. For 1 thing, maybe they don't know which
> > extreme will try order-reversal. Also, anytime defensive 
> > strategy requires you to insincerely raise someone in your ranking,
> > that can give away the election when you misjudge and do so
> > when you didn't need to. That's the trouble with drastic
> > defensive strategy.
> 
> Remember that the whole purpose of the truncation strategy is to give
> the election away.  It cannot make your candidate win, it can only make
> the order-reversers lose.
> 
> Furthermore, I suggest that the normal pairwise defense strategy is more
> natural than the Votes-Against truncation strategy.
> 
> For example, lets say my preference is 
> B > C > A  with B being the suspected Condorcet winner
> 
> Now, I here that A is mounting an order-reversal or truncation
> campaign.  This probably confirms my worst suspicions about them.  So,
> what does the truncation defense strategy suggest I do about this?  Rank
> B > C = A.  That is, increase A in my ballot.  Is it because this will
> help B win?  Well, not exactly.  On average my change of vote will hurt
> both B and C.  I am doing it so that if C order-reverses too, then A
> might win.  A is my last choice remember.
> 
> This just seems totally unnatural to me.  What seems more natural is
> that people who would have voted B > A > C will now consider B > C = A 
> to punish A voters for their conduct. And that people who would vote B >
> C = A will now consider B> C > A.
> 
> This is a clear punishment and deterrent to A in both methods.  I think
> it is important to remember that the real purpose of order-reversal
> punishment strategies is as a deterrent.  If the deterrent is strong
> enough, no one will attempt to organize order-reversal campaigns.
> 
> You also mention the possibility that you do not know who will be doing
> the order-reversal.  Well, if both sides have order-reversal campaigns,
> both deserve to be punished.  You cannot punish them both under any
> method.
> 
> I am not sure whether I would ever accept a method that violates SEC. 
> Such a method seems somehow fundamentally dishonest, or at least
> confused.  However, I do know its violation would have to be offset by
> tremendous advantages, and I do not see this with Votes-Against.
> 
> 
> 
> -----== Sent via Deja News, The Discussion Network ==-----
> http://www.dejanews.com/  Easy access to 50,000+ discussion forums
> 
>