[EM] Contd., Miscellaneous comments on MMPO & MDDA

MIKE OSSIPOFF nkklrp at hotmail.com
Mon Jun 27 19:48:26 PDT 2005


At first I thought that you meant that, by electing the candidate whose 
least votes-for is the greatest, that would guarantee that how you order A & 
B would have no effect on whether the winner comes from {A,B}.

Right after posting my first-glance reply, I noticed that voting A over B 
increases one of A's votes-for, and that could be A's least votes-for. So 
you didn't mean that that method ensures that how you order A & B can't 
affect whether the winner comes from {A,B}. Too bad, because it would be 
nice if that could be guaranteed.

It would be a little like having Strong FBC.

If that were attainable, that would be worth giving any other criterion 
compliances for.

I'd  said:

In MDDA, the voter should sometimes do that, but sometimes should
>       the unacceptables. For instance, if it's certain that the 
>acceptables can't beat the
>       unacceptables at Approval, then the only hope is to disqualify the 
>       and that goal is best helped by ranking them, in reverse order of 

However, in MDDA, this could have the effect of causing a "least winnable"
unacceptable candidate to win instead of an acceptable candidate. In MMPO,
that couldn't happen.

I reply:

Why not? Say Howard Dean is the most winnable unacceptable, with Jeb Bush as 
the other unacceptable. Say the method is MMPO. I move Howard Dean down to 
the bottom of my ranking (Power truncation isn't available). Now I'm no 
longer giving Bush a votes-against from Dean. Say one other person does the 
same thing. Maybe Dean is Bush's worst votes-against. Maybe Bush was only 
one vote-against worse than Nader. So, by upranking Bush, I've changed the 
winner from Nader to Bush.

But it's still good strategy to rank the unacceptables in reverse order of 
winnability, because, judging by our best information, that minimizes the 
chance that one of them will win.

You continue:

It seems to me that MDDA is less friendly to order-reversal strategies than
MMPO is. That seems like an advantage to me.

I reply:

Yes on both statements. With MDDA, it's often or usually better to not rank 
any unacceptables, instead of ranking them in reverse order of winnability. 
But the fact that sometimes truncation is better and sometimes strategic 
ranking is better could create a dilemma for the person who wants to know 
whether to truncate or strategically rank.

You said:

I wonder if you saw this scenario, under MMPO:

n A
1 A=C
1 B=C
n B

When n>2 then C wins decisively, no matter how large n gets.

I reply:

What an embarrassment. Yes, that's a ridiculous result, when increasing the 
A & B voters without bound makes them both lose.  Does that clinch it for 
MDDA over MMPO? Too bad, because there were things I liked about MMPO. But 
if someone showed that example during the enactment campaign, we might as 
well forget about MMPO being enacted.

Mike Ossipoff

Express yourself instantly with MSN Messenger! Download today - it's FREE! 

More information about the Election-Methods mailing list