[EM] How much strategy-freeness can be attained?
mikeo2106 at msn.com
Wed Mar 7 02:12:05 PST 2007
SFC describes conditions under which a voter doesnt need any strategy at
all. Are there ways of achieving that under broader conditions?
Yes, thats what ARLO does.
But are there other ways? To get more strategy-freedom under more
Summer 04, I asked if a method could guarantee that if a majority prefer
the CW to Y and rank sincerely, Y wont win. Without stipulating that no one
falsifies. I realized that it can be achieved by disqualifying every
candidate with a majority pair-wise defeat. And not saying (unless that
disqualifies all the candidates).
But then there might be no winner. In public political elections that isnt
acceptable. So hold another election? Maybe the order-reversers would keep
repeating their strategy so that there would never be anyone elected. So the
method would be too indecisive for public political elections.
So that goal is unattainable. That puts a limit on how much
strategy-freeness is attainable. For instance, it tells us in advance that
solutions like the one in the next paragraph cant work:
With some methods, like Condorcet, MDDA & MAMPO, you can make someone worse
win if you increase the pair-wise vote against a somewhat favorited
candidate. So an obvious solution would be an option to just say that if
that happens, you want to not have that pair-wise preference of yours
counted But if other people do that too, the count result might keep
changing cyclically endlessly. If one limits how many times the option is
applied in the count, or doesnt allow a voter to cancel his use of it, then
who knows where the cyclical change will stop. Maybe with the election of
one of your least favored candidates. This option amounts to trying to use
ARLO in a finer way. Attempts like that tend to fail.
So, for an option along those lines, ARLO is probably the best that one can
realistically do. With its protection, for a particular voter, limited to a
particular set of candidates en-bloc, and with only a 1-time application of
However, Id be interested if anyone else can improve on ARLO, or apply it
more finely for better strategy-freeness enhancement.
Some time ago I suggested other, more automatic, options.
One was an option for the voter to ask the count program to look for
certain indications of unanimity of pair-wise votes. That option seemed to
have some promise, but I havent felt that its simple or perfected enough
to propose, so I wont detail it here. But the idea was that a comparison of
the unanimity of the pair-wise votes could give a good indication of who
is order-reversing. The voter could have the option of asking the count
computer to watch for that, and, if detecting it, to automatically apply
counterstrategy on his ballot.
Another more automatic option that Ive suggested was one that lets the
voter specify the political spectrum ordering that he expects. Then
certain kinds of violations of that ordering by some voters could indicate
that someone is offensively order-reversing, and if a voter has chosen this
option, it would trigger automatic counterstrategy on that voters ballot.
The unanimity option is more automatic, because it doesnt require any
information from the voter, other than the fact that s/he wants to use the
Both options seem to have merit, but theyre for a more distant future, when
more complicated enhancements are acceptable, and when/if people feel the
need for more strategy-freeness enhancement.
Id be interested in any other suggestions for increased strategy-freeness
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