[EM] voting strategy with rank-order-with-equality ballots

[Chris Benham]

Warren,

"How true is it that approval-style voting is "strategic" for Schulze?"

Not very true. It depends on the voter's information and  sincere ratings.
Schulze, being a Condorcet method fails Favourite Betrayal.

"Is Schulze with approval-style ballots a better or worse voting system 
than plain approval?"

If approval-style ballots are compelled than Schulze is the same as plain
Approval.  If they are merely allowed  (as Marcus Schulze and other 
proponents favour) then in my opinion it is better than Approval.

In the zero-information case, the voter with a big enough gap in hir sincere ratings
does best to rank all the candidates above the gap equal top and to strictly
rank all those below it  (random-filling if necessary in the absence of a sincere
full ranking).

I find it preferable that the zero-info. strategy for a ranked-ballot method be either
full sincere ranking regardless of  relative ratings (as in IRV and Margins) or  sincere
ranking above the big ratings gap and truncation below it  (as in Smith//Approval).

By  "Shulze"  I have been meaning  Shulze(Winning Votes), the 'standard version'
favoured by Marcus himself and other proponents. 

In January this year I suggested a different version I prefer:

http://lists.electorama.com/pipermail/election-methods-electorama.com/2009-January/023959.html


Chris Benham


 
 Warren Smith wrote (8 June 2009):

One problem is nobody really has a good understanding of what good strategy is.

If one believes that range voting becomes approval voting in the
presence of strategic voters (often, anyhow)...

One might similarly speculate that
strategic voters in a system such as Schilze beatpaths ALLOWING ballots
with both > and = (e.g. A>B=C=D>E=F is a legal ballot)  usually the
strategic vote
is "approval style" i.e. of form A=B=C>D=E=F, say, with just ONE ">".
One might then speculate that Schulze, just like range, then becomes
equivalent to approval voting for strategic voters.

Well...  how true or false is that?   Is Schulze with approval-style ballots
a better or worse voting system than plain approval?

How true is it that approval-style voting is "strategic" for Schulze?

I'd like to hear people's ideas on this question.  (And not
necessarily just for "Schulze" -- substitute other methods too, if you
prefer.)

The trouble is, range voting is simple. Simple enough that you can
reach a pretty full understanding of what strategic range voting is.
  (Which is not at all trivial,
but it can pretty much be done.) In contrast, a lot of Condorcet
systems including Schulze are complicated. Complicated enough that
making confident statements
about their behavior with strtagic voters (or even undertsnading what
strtagy IS) is
hard.

Frankly, I've heard various vague but confident claims about strategy
for Schulze & the like, and my impression is those making the claims
know very little about what they
are talking about.  I also know very little on this, the difference is
I admit it :)


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