Margins truncation example

David Marsay djmarsay at
Wed Nov 11 05:44:43 PST 1998

Mike Osipoff  wrote:

> Here's an example where Margins fails the strong 1st Choice
> Criterion due to truncation. Numbers of voters don't add to 100.
>  101  50  75
>    A   B   C
>            B

A thought:

Mike supposes that A and C's real second choice is B, and B 'should' 
win. If A truncates, C can only win if B does not truncate, or if C 
has more support than A. If I were a C supporter, I'd seriously 
consider truncating too. Then we have FPP.

It seems to me that it is the moderate party's supporters who have no 
incentive to truncate. In MIke's example, if C is the real moderate 
then it 'should' win, not B. So it margins so bad?

Under AV / IRO B's supporters have every incentive not to truncate 
IN THIS CASE, else their vote may be wasted.


Sorry, but apparently I have to do this. :-(
The views expressed above are entirely those of the writer
and do not represent the views, policy or understanding of
any other person or official body.

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