[Election-Methods] Two replies
Abd ul-Rahman Lomax
abd at lomaxdesign.com
Sat Aug 11 20:40:07 PDT 2007
At 12:58 AM 8/11/2007, Juho wrote:
>I don't want to define/redefine "strategic". The technical properties
>of the votes are enough.
Two opposite statements made in the same two-sentence paragraph. Juho
has redefined "strategic." Strategic votes have never been defined
from the vote alone. Rather, a "strategic vote" has referred, in
ranked methods, to a vote where the voter reverses a preference in
order to gain some advantage. Another term used is "forced
strategic," where the voter, again, reverses a preference because to
express the true preference would cause a poor outcome, sometimes
even worse than not voting at all.
The extension of "strategic" to include votes which involve
expressing an equal rating for candidates when the voter actually has
a preference is, in my view, properly controversial. Few have called
equal voting in Approval "strategic," nor does anyone call the
bottom-equal voting for all candidates but one in Plurality
"strategic." (But top rating other than the favorite in Plurality is
a preference reversal, and certainly is strategic.)
However, until now, *nobody* has claimed that a vote is "strategic"
because of its form, regardless of intention or the true preferences
of the voter. Juho is claiming that voting max and min in Range is,
ipso facto, "strategic." He has not even qualified the statement to
make it clear if this covers *any* use of min and max, though I think
he did say that a strategic vote was one which did not use
intermediate ratings.
So, suppose a voter, in a three candidate election, votes A max, B
min, and leaves C blank. Is this "strategic?" What if the election is
default zero (i.e., it is sum of votes Range) and the voter only
marks A max? Is this "strategic."
Note that if a voter does not vote min and max for at least one
candidate each, in Range, the voter is weakening the vote. Juho's
arguments about the alleged harm of "strategic voting" all included a
so-called "sincere" voter who did not vote the extremes, and then,
because the outcome went as voted by those who *did* use the extremes
-- something we expect to be the norm, particularly for frontrunners
in a 2-party system, allegedly there was a "bad" outcome.
>I wrote:
> >> Range could ignore also a clear majority
> >> opinion.
>
>I should have written "a clear majority and utility opinion as a
>result of strategic voting".
There is no meaning to "a clear utility opinion," that I know of. We
only know opinions two ways: expressed and simulated. Expressed
opinions are how people actually vote. In simulations, we assume some
internal preference rating scale, but this has never been called a
"utility opinion."
No election method can use data which is not expressed on the
ballots. Range *allows* voters to express finer gradations of
preference. If voters don't use them, the method cannot satisfy the
voters as efficiently. Further, if voters translate their preferences
to Range votes in a totally silly way, which is what Juho proposes
some will do, a way that conceals the true strength of their
preferences in context, the method likewise cannot fully take them
into account.
Juho proposes one set of voters who, quite intelligently, translate
their internal preferences to Range Votes that include the endpoints;
another translates them in a way that doesn't use the full Range.
Range, of course, gives more weight to those who express the full range.
Range N is quite like having N votes to cast, in an Approval
election. If you don't cast N votes, but, say, N/2 votes, it is quite
like a half-abstention. And if you and those like you abstain, how
can we call a result which does not fully consider your defectively
expressed opinion "bad."
When I first started working with Range, I suggested that votes might
be normalized. That is, one would take the range of values used by
the voter and expand them, if necessary, so that the voter was
casting one vote.
However, deeper reflection led me to the conclusion that this was a
complication of counting that was unnecessary. It's highly unlikely
that significant numbers of voters would fail to use the full range,
except as a protest. And if voters want to protest, why not let them!
Why modify their votes to what *we* think they should be!
Juho *could* have focused on the use of intermediate votes *in
addition* to the use of extreme votes. But he did not. His examples
of "bad" outcomes involved an election, for example, where the Dems
voted 100 for the D, 80 for R1, and 70 for R2. What we have is all
the Ds casting 0.3 vote each! Then come the Republicans supporting
R1, and 30% of them also vote in this crazy way, 100 for R1, 90 for
R2, and 70 for D.
Finally, the supporters of R2 vote Approval style, 100 for R2 and 0
for R1 and D.
Now, in a real election, this voting pattern is extremely unlikely.
Because 50% of the electorate, it was proposed, is D, the Republicans
would know that if they split their vote, the D is likely to win.
Only the utter insanity of the way in which all the Ds are supposed
to have voted is what makes a Republican win.
We have noted that if all voters vote sincere absolute utilities,
Range maximizes social utility. *However*, it is rare that voters
would even know what their "sincere absolute utilities" were.
*Nobody* is recommending that voters vote other than the full Range.
And what we expect to see, in the implementation of Range, is quite
possibly gradual. That is, we start with Approval.
Now, if Approval voters voted the crazy way that Juho is proposing
Range voters may vote, The Ds might approve all candidates. Thus
totally abstaining from the election....
No, one might say, they would set an approval cutoff above R2, at
least, maybe above R1. Mean-based approval would suggest that they
Approve only D. (And, by the way, that the Rs vote to approve both
Rs, and in this context, the danger to the R2 supporters of voting
the strategy they voted, if it was a strategy and not sincere, would
be apparent. They would throw the election to the Ds by refusing to
also approve the other Republican. The same thing would happen in
Range, quite likely.
> > > One could e.g. translate utility values 1
> > >A=90, B=80 and 1 B=90, A=70 to actual votes 1 A=100, B=0 and 1 B=90,
> > >A=70.
> >
> > So this is two voters. Thus it is 50-50 as far as first preference
> > is concerned. (And we can imagine that this is two whole sets of
> > voters voting identically.) Fine. If I'm correct, Juho is asserting
> > that, if the votes are translated as stated, the outcome is "bad."
> >
> > Yet what method is going to do better than Range in this example?
>
>Range changes the winner depending on the level of strategic voting.
>Most other methods would give a tie.
Juho is inventing new language, and quite misleading language. The
true statement is that Range can change the winner according to the
expression of preference strength. Juho calls the expression of
strong preference "strategic," though this is totally outside normal
usage of the term.
If we are talking about what to do, and you say that you *strongly*
prefer A over B, and I say that I have only a small preference for B
over A, what is our likely conclusion, assuming that there is no
third choice C?
Most people would have no trouble with considering A the better
choice. Only if time after time, a person expressed strong
preference, and the other began to suspect that it was exaggerated,
or simply got tired of never getting his or her first preference ...
what would happen?
Naturally, the preference of the second person would increase. This
is not "strategic voting" in response, it is a natural reaction to
balance out a series of small losses. (or, more accurately, smaller
gains than preferred).
But if I knew that the strong preference of a person was soundly
based, I would not start to discount it simply because I was
continually not getting my first choice. However, I'd presumably be
careful to fully and accurately express my own preferences in such a
way that the comparison of mine with the other person was fair.
We expect most people to start out voting Range quite as if it were
Approval. It's what they are accustomed to. But there are two very
important exceptions, and Juho seems strangely uninterested in them.
Supporters of third parties would have a choice. Let's assume that
it's Range 2, the lowest resolution Range that isn't Approval. They
could equal-rate their favorite and the preferred frontrunner, quite
as they would probably do in Approval, or they could give the
frontrunner a half-vote. If they do the latter, they are possibly
wasting a half-vote. However, there could be reasons they would want
to do this. Perhaps the frontrunner they prefer snubbed them, so this
is a protest, but not as drastic as not voting for this person at all.
On the other hand, suppose that the preferred frontrunner is truly,
to them, almost as bad as the other one. The half-vote is actually
quite a good vote, in some ways better than the Approval style vote
of 110. If there is *any* chance that the third party candidate might win.
>-------------------------
>
>On Aug 11, 2007, at 5:50 , Abd ul-Rahman Lomax wrote:
>
> >> > D R1 R2
> >> > 50: 100 80 70
> >> > 30: 70 100 90
> >> > 20: 0 0 100
> >> > ---------------------
> >> > 7100 7000 8200
>
> > In any case, what is "bad" about this scenario?
>
>The success of the strategic voters.
Why is it bad for someone to be successful?
These voters are voting as they are allowed, and to some degree
encouraged, by the system. If the other voters had voted in a sane
way, the R2 vote actually would have been a serious loss for them;
but they lucked out.
The D and R1 voters indicated strong support for R2! So why should
the method not choose R2?
Now, the way the R2 voters voted was not merely "Approval style."
Approval style voting would have had them vote D:0, R1:100, R2:100.
That's mean-based approval. Now, suppose that this is an Approval
election. If the Ds and the R1 supporters vote mean-based Approval,
and we assume that the D and R1 votes above were "sincere, but not
fully normalized, utilities," we get 50 votes for D, and then, if the
R2s vote "sincere, mean-based Approval, 30 + 20 votes for R1 and R2.
A three-way tie.
However, we have postulated that the R2s are betraying their second
favorite. So they vote as described before, and it is a two-way tie
between D and R2. And the R1 supporters are quite upset with them....
As they would be in the Range election described.
This has little to do with election method. In Approval, the R2
strategy defeats R1 without defeating the D. In Range, the Ds voting
sensibly -- even a relative few of them, which I mentioned and Juho
dismissed -- would have cause the D to win, and the betrayal vote of
the R2 supporters would have been the cause.
This scenario does not show bad behavior of Range.
> >> They were intended to be strategic/exaggerating republicans whose
> >> sincere opinion could have been e.g. R2=100, R1=90, D=70.
> > These are not normalized utilities, on what basis are they made
> > commensurable?
>
>The problems rose from some voters normalizing or exaggerating and
>some not.
Of course. What would you think if voters voted A=2, B=1, C=0. In Range 100?
Range allows you to vote fractional votes. If you decide to only cast
a fractional vote, can you blame the system for only giving you
fractional power?
Different issues get mixed. It is conceivable that some voter could
be confused by the system, especially if high resulution Range were
implemented and poorly explained. As I've noted, if the ballot asks
you to "rate" candidates, it might encourage a misunderstanding,
unless it is made clear that if one does not use the full range in
the election, at least one candidate max and one min, the vote is
weakened. And that is probably a more complicated explanation than
should be on the ballot, so I would simply describe Range N as
casting 0-N votes for each candidate, with the election going to the
candidate with the most votes.
Practically speaking, we should see Approval first, so voters would
be accustomed to the idea that you can vote full strength for more
than one candidate.... And intermediate votes would probably be
introduced gradually, perhaps starting with Range 2 or 3.
> > So on what basis does Juho assume utilities as he did. Why is the
> > worst candidate in the set a "70"?
> >
> > He is postulating circumstances that are unreal.
>
>Any reasons and votes that give other than min and max values will do.
Do for what? What Juho is saying that if voters vote weak votes, they
have a weak effect. Yes, they do. Is this a criticism of Range?
If I vote 70 for a candidate, as these Ds did for the *worst* R, R2,
from their point of view, they are saying that R2 is quite a good
candidate! If they would be upset that R2 is elected -- isn't that
what a "bad outcome" would mean? -- then why did they vote such a high vote?
Juho has asserted that these are sincere utilities, but he has
totally avoided the question of what they mean. What *kind* of
sincere utilities? How was the scale set? Does 70% mean "acceptably
good," as I would normally assume in 0-100 Range -- it's been
proposed, sometimes, that 50% be made explicit as an Approval cutoff,
and that is what is done in mean-based Approval, essentially. (The
ratings are normalized to the candidate set, then one approves any
candidate above 50%.)
> > A major contradiction in Juho's argument is that he assumes that
> > voters would vote a weak vote in Range but that they would
> > accurately predict which form of Approval vote would serve them
> > best, and they would not vote a weak vote in Approval.
>
>I don't want to claim anything about Approval or Approval like
>strategies.
He's made a claim about an "Approval-like strategy." That it leads to
a "bad" result. He is not explicit about what he is comparing the
method with. Bad compared to what? Or just *absolutely* bad?
> > If the Ds considered R2 a poor choice, why did they rate him at 70?
> > *That is a high rating.*
>
>They didn't consider R2 to be a poor choice (although R2 was to them
>the worst choice).
That's right. They considered him a good choice, apparently. So, in
the face of that, why shouldn't R2 be elected? The Ds consider him a
good choice, the R1s consider him a better choice, and the R2s
*really* want him.
(That they have "sincere" utilities of 100, 90, 70 is actually
inconsistent with their vote of 100, 0, 0. Now, if the supporters of
R2 are going to show "exaggeration," why don't the supporters of R1
and the Ds? Somehow, this particular kind of "sincerity" -- I'd call
it pure foolishness, *unless* this really is a consensus election,
and the Ds and R1s will really be happy with the outcome -- is
confined to R1 and D supporters.)
> > Who would be a better winner?
>
>R1 and D based on social utilities (and according to the choices of
>many methods).
First of all, election methods don't define what is a good winner.
There really is only one standard that has been proposed that makes
any sense, and that is S.U., or perhaps a little more clearly,
expected voter satisfaction.
Juho did not provide us a basis for concluding that R1 and D are
better winners. To conclude that, we would have to know how to
compare the utilities of the D, R1, and R2 winners. The utilities he
stated are "half-normalized." That's odd. In order to compare and sum
S.U., the ranges of utilities need to be tied to each other in some
way, so that they are commensurable, so that summing them has meaning.
I discussed this at some length, but it seems it sailed past Juho.
Then, we know that Range does not always maximize S.U., there are
better methods than simple Range. For example, Range+2 (Range with
top-two runoff) does a better job. Why does Range not always maximize
SU? There are a number of reasons, and one of them is that voters
won't vote accurate utilities. There are two reasons for this; the
first is normalization to the candidate set, which causes weak
preferences to be equated with strong ones, in some cases, and the
second is inaccurate voting, most particularly, what Juho calls
"exaggerated voting."
So it is utterly unsurprising that you can construct a scenario where
some pattern of voting by voters causes Range to not elect the SU
winner; in this case, the R2 supporters, by understating their "real
feelings" about D and R1, elect R2. However, the way in which they
are shown as having voted would be highly risky in the real world. It
is utterly unsurprising that they would vote 0 for the Democrat. This
is what we would have expected for the R1 supporters, also, and for
the Ds we'd have expected the reverse. What is unusual -- and quite
dangerous for them -- is that they voted, in a tight election, 0 for
R1. They violated standard Approval strategy to do this. There is a
reason for that strategy! Only bizarre behavior on the part of the D
and R1 supporters caused them to prevail.
No method can maximize SU if the voters conceal it! However, the
question is really, "Who is harmed by concealing it?" In this case,
in a normal election, it would have been the R2 voters who would have
been most harmed by concealing their support for R1. And, as it was,
the Ds and R1s -- if we accept Juho's assertion that the outcome was
"bad," *also* concealed their preferences.
No election has had a "bad" outcome if all the voters consider it a
good one! And Juho ackowledged above that the Ds considered R2 "not a
poor choice."
Not a poor choice is, quite simply, not a "bad" choice. Juho has
contradicted himself, in more than one way.
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