[EM] strategy and method complexity and the advantage of minmax methods

[Anthony Duff]

I do not suggest that anyone has lied, but I do wonder whether these
people who have told Mike that they frequently have an incentive to
betray their favourite under IRV really understand what they said, or
if they even understood the tally method of IRV.  I have queried a
lot of Australians on how they understand IRV and found that about
half do not.  Many understand only that they use a rank ballot and
that the winners are known about two hours after the close of polls. 
A surprisingly large minority believe that the winners are determined
by a plurality count based on their first preference, and they don't
see the purpose of later preferences.  This would account for some of
the information given to Mike - they were acting as if the method was
plurality.  (Aside: I am yet to meet another Australia face to face,
other than an electoral worker, who can explain the principles of STV
tallying.)

So, I am voicing my opinion that claims of widespread strategic
voting in Australia should be subjected to some doubt.

The pertinent question is whether people here have wildly exaggerated
the importance of strategic voting, and whether simple minmax
methods, such as PC or MMPO are good enough.  

My impression is that the rampant strategic voting that occurs in the
US is caused by the use of plurality.  I have lived in America, and
discussed politics and voting with Americans, and it was obvious that
the need to betray a favourite to vote for the lesser of two evils is
apparent to most Americans.  I suspect that if Americans were given
any rank ballot to vote on, then the practice of strategic voting
would decline significantly, over time.  

I believe that the difficulty in organising the public at large into
voting insincere preferences so as to generate an insincere cycle is
too great to be realistic.  One problem is that the presumption is
that they themselves do not represent majority and that a majority
prefers another candidate to their candidate. 

To justify more sophisticated methods, you then have to consider the
improbability of organised strategic voting in a case where there are
more than three contenders.  [with PC giving the same results as
Ranked Pairs, beatpath, etc when there are less than four contenders]
 How many public elections do you think there will be where there are
four or more serious contenders.  In Australia, under IRV, where
there is no penalty in the tally method against running multiple
similar candidates, three serious-contender-elections are rare and I
have never heard of anything beyond that.  So, even if you think
strategic voting is a real danger, I still say that PC is good enough
because having four or more serious contenders in a public election
is unrealistic. 

The real advantage of PC is not that its better than another method,
but that it has a realistic chance of being sold and properly
adopted.  It needs to be sold to the public, but more than that, it
needs to be understood by the politicians.  How many politicians have
been made to appreciate the subtle advantages of any of the more
sophisticated methods?  I suspect none, and a real danger here lies
in the fact that whatever the electoral method, it is going written
up and legislated by politicians.  It is not in the nature of
legislators to refer to external definitions, such as your own.  They
are going to reword your definitions, as they understand them.  They
might also stick a preamble on the bill that contradicts the details
of the bill.  Then, the first time there is an interesting election,
the whole thing then goes to the courts who make their decision based
upon the intention of the legislature that didn't even understand the
method.

At least with a minmax method such as PC the rule is simple.  The
winner is the candidate who suffers the weakest defeat.  This would
even be straightforward to defend in court:

Suppose candidate A won but suffered a defeat by candidate B.
Candidate B goes to the courts to argue that as B beat A, a win by A
contravenes the intention of the bill, and is contrary to the meaning
of democracy itself....
If the method was minmax, candidate A can argue that the argument
made by B against A is weaker than the identical argument that would
be made by some other candidate C against B, that if a win by A is an
injustice, then a win by B is a worse injustice.  I think this is a
simple and coherent enough argument to be understood by a politician
(for the law to be written) or judge (for the law to be interpreted).


If the method were any condorcet method other than minmax, then the
arguments would be more complex, and I would predict that the
arguments would become convoluted and that the judges would be unable
to reconcile reality with whatever the legislators wrote.    


I think that the principle of condorcet, of a full pairwise analysis,
is simple enough for most people to appreciate, and that abandoning
the pairwise principle of analysis in order to perform the rare
completion is not simple enough for most people.  I don't think that
complicated strategising in extremely rare
more-than-three-contender-elections is enough of a concern to warrant
introducing a method that most people won't understand.

Anthony

ps.

What are the differences in strategic implications between PC and
MMPO?  I recall that in going from PC to MMPO you loose several
things to gain later-no-harm.  I think later-no-harm is very
desirable because it means that the voters can be truthfully
encouraged to rank as many candidates as they like.  Without
later-no-harm, I think bullet voting would be a problem.  So, what
are the PC benefits that are lost, and how desirable are they? 




--- MIKE OSSIPOFF <nkklrp at hotmail.com> wrote:

> 
> Anthony--
> 
> I'm glad to get the opinions of people in Australia, about IRV
> strategy in 
> Australia.
> 
> I've heard from about 5 Australians about that. Three told me that 
> favorite-burial is common in Australian IRV elections. Two
> (including you) 
> told me that they haven't heard of it.
> 
> One could argue that the three who told me it's common were lying.
> But why 
> would they lie?
> 
> Isn't it more plausible that the two who haven't heard of it just
> happen to 
> have not talked to the people who vote that way (and admit it)?
> 
> One of them even told me that she herself had voted a lesser-evil
> compromise 
> in 1st place, over her favorite, in the most recent election. Was
> she lying? 
> Why would she lie about that?
> 
> One of them told me that it's difficult for the smaller parties to
> get their 
> members to rank them in 1st place, because they all want to rank a
> big-2 
> lesser-evil in 1st place instead.  He said that voters say that
> they're 
> doing that to avoid wasting their vote.
> 
> One Australian told me that they don't vote that way because they
> know about 
> IRV's specific  faults. They do it because they assume that the
> situation is 
> as it is in Plurality (First Past The Post). And of course, to a
> significant 
> extent they're right, with IRV. He didn't say they don't vote that
> way. He 
> said they do it because they assume the situation is as sit is in
> Plurality.
> 
> People have complained that the 5 Australians I've talked to don't 
> constitute a scientific statistical study. I have nothing against a
> 
> scientific statistical study. But, in the meantime, I merely tell
> the 
> information that's available so far.
> 
> Mike Ossipoff
> 
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