[EM] IMHO, IRV superior to approval

[Chris Benham]

Stephane,
I  also rate IRV  above Approval, for many reasons. For a method to be 
acceptable to me, it must meet  Majority for solid coalitions (Woodall 
calls "Majority" and  others call  "Mutual Majority")  and  Clone 
Independence(Woodall's  Clone-winner and Clone-loser
criteria). Common-sense, Mike O. and I  agree that  Approval fails Clone 
Independence.  Some may sneer, but these criteria are
easy to meet; and failing them allows  all sorts of  unfairness and 
absurdity.

I  like methods that have no zero- information strategy, and  doesn't 
reward  indecisive voters by giving them extra clout.  If  voter  A
ranks candidate X last,  and  because of  prejudice, ignorance and 
stupidity has no ranking of the other candidates; and voter B ranks
candidate Y last but also strictly ranks all the other candidates; then 
both candidates X and Y should have the same probabilty of being
elected. (From this point of view, if equal-ranking is allowed, the 
split-votes version is better than the whole-votes version. If  the 
whole-votes version is used, then there should be no majority stopping 
rule.)
"No Zero-Information Strategy"  also implies that Later-no-harm and 
 Later-no-help should be in balance. That is, that the chances of
harming or helping an already ranked candidate by ranking another below, 
should be the same.

This is from my Tues.Mar.2 post:

"To my mind, Approval does NOT satisfy Independence of Irrelevant Alternatives (IIA), or even
the much weaker Independence of Clones.
For my demonstration, I am assuming that the voters know nothing but their own sincere ratings
of all the candidates on the ballot, and that in that situation they all use the best "strategy"
of approving all the candidates they rate above average, and no others.

Initial two candidate election (with ratings out of ten).
01: A(9)>>B(1)
99: B(8)>>A(7)

B wins 99 to 1. Now we add a third candidate X, which all the voters rank adjacently to A, and who
therfore meets the Blake Cretney definition of a clone of A. 

Same voters and initial 2 candidates, but with a third candidate added.
01:A(9)>>X(2)>B(1)
99:B(8)>A(7)>>X(1)

A wins 100 to 99. So adding a clone of A, which ALL the voters ranked last, changed A from a 
1/100 loser to the winner.

One of my fundamental standards is that a method should perform reasonably when all the voters
vote sincerely (taking no account of how any other voters might vote). 
A method should be able to cope with insincerity, but to perform reasonably it definitely shouldn't
DEPEND on insincerity."

Isn't that enough "unfairness and absurdity"?

I agree that "defensive srategy citeria" are valuable, but the starting point should be that the 
method is, and appears to be, fair and sensible if all the voters vote sincerely.
Approval is based on the assumption that all the voters strategise, and in effect invites them to
do so; because it doesn't even give voters who have a strict ranking and who want to vote sincerely
a clear-cut instruction on how to do so. Instead it leaves them wondering why they should "vote for"
more than one candidate, and if they should, then how many more.

Approval would be less unacceptable if the ballot instruction was at least concise and semi-sensible.
Either "Check the candidates you rank in equal-first place. Barring candidtes you rate as unacceptable,
check the other candidates you rate as above-average in this field", or the simpler "Of these 
candidates, check those you rate as above average".
But according to Approval advocates that I've been in contact with, there definitely shouldn't be
"strategy advice" on the ballot paper. Oh no, there should just be the infuriatingly meaningless
"Vote for" whichever candidates you choose.

Another thing I hate about Approval is that elections in the US are apoltical enough as it is.In
election campaigns, voters should be thinking about politics, and the policies and qualities of 
the candidates. Approval would help get rid of that, by turning the election into a kind of sport
between rival factions of strategising voters. Tv debates and newspaper articles could be all about
"what is the best Approval voting strategy?". Also of course, obsessing about polls will be
intensified. Maybe everytime a new poll is published, tv reporters will ask Mike Ossipoff "What does
this new poll mean for voters who want to maximise the effect of their vote?"
And of course voters who succeed in ignoring this circus and instead just concentrate on the 
policies and qualities of the candidates, will potentially be greatly disadvantaged (much more than
a "naive", sincere IRV voter).

Chris Benham




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