Margins -- Blake is right -- slight amplification (fwd)

Markus Schulze schulze at
Thu Oct 1 08:17:19 PDT 1998

Bart Ingles wrote (27 Sep 1998):
> I bet many voters would have a problem with a winner who
> had a very small percentage of the first-choice vote.
> A compromise winner would have a better chance of acceptance
> if he is at least in the ballpark in terms of first-choice
> votes. Maybe non-IRO methods could be improved by reverting
> to IRO to eliminate very weak candidates or in case of a
> circular tie, etc.

At least in Germany, we have nomination by petition.
200 signatures are needed to be allowed to run for
the parliament ("Bundestag"). Every voter is allowed to
sign only one petition; if a voter signs more than one
petition, this voter's signatures becomes invalid on
every petition. Thus, I believe that -at least if every
voter votes for his most favourite candidate- every candidate
will get at least 200 votes. Thus, I believe, that there is
no need for extra rules to get rid of "very weak candidates."

Hugh R. Tobin wrote (22 Sep 1998):
> I use "truncation" to refer to omitting to express
> preferences at the bottom of one's ballot when one actually
> holds such preferences.

I believe, that as soon as the voters understand, how
Condorcet election methods work, the probability, that a
voter will rank two candidates equally, will be identical
for every position. Thus, "truncation" should mean, that
a voter ranks candidates equally although he actually
holds such preferences.

Blake Cretney wrote (29 Sep 1998):
> All voters who know how Votes-Against works will use the
> random-fill strategy instead of sincerely or insincerely
> leaving candidates unranked.

This is not true. Of course, if you use Condorcet[EM] or
Smith//Condorcet[EM], then it will be a usefull strategy
to rank the remaining candidates (sincerely or randomly),
because if Condorcet[EM] or Smith//Condorcet[EM] is used,
then the worst defeats of your less favourite candidates
cannot decrease by ranking these candidates (sincerely or

But if the Schulze method or the Tideman method is used,
then this strategy won't work, because the strength of
a pairwise defeat has only an influence on the question
which beat-path is used or in which order the pairwise
defeats are locked. Thus, the strength of the pairwise
defeat of your less favourite candidates has no immediate
influence on the scores of these candidates.

For the Schulze method, the Tideman method and most other
Condorcet methods, the random-fill strategy doesn't work,
because it is not guaranteed that the scores of the less
favourite candidates get worse by ranking them.

Markus Schulze

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