[EM] MMPO vs MDDA, contd.

MIKE OSSIPOFF nkklrp at hotmail.com
Mon Jun 27 20:17:23 PDT 2005

My concern with voting systems is: If someone else who, like me, prefers 
Nader thinks s/he needs to help Dean, I don't want him/her to 1) give the 
election away to Dean; or 2) conceal his/her preference for Nader over Dean; 
or, worst, 3) indicate a false preference for Dean over Nader.

MMPO & MDDA get avoid that 3rd problem with 100% reliability, or course, if 
the voter can be shown that those methods meet FBC.

I'm going to abbreviate "acceptable/unacceptable" as "a/ua".

If it's a/ua for every voter, and if power truncation is available, and 
everyone votes optimally, then MMPO & MDDA are Approval.

I was previously asking about when it's a/ua, and power truncation isn't 
available. In this posting I want to ask what if it isn't a/ua.

Under those conditions, people might rank even their better candidates in 
different rank positions. The lesser-of-2-evils (LO2E) progressives might 
rank Dean in 2nd place. They're the voters that I'm concerned about.

Which method, MMPO or MDDA, makes it less likely that those LO2E 
progressives will regret ranking Dean in 2nd place, instead of in 1st place 
with Nader?

MDDA. In either method, ranking Dean in 2nd place instead of equal ranking 
him in 1st place will give Dean a votes-against from Nader. In MMPO that 
will worsen his score by one vote if Nader is his worst votres-against. In 
MDDA it will do so if Nader is the who can be made to have a majority 
against him with one more vote. But that requires that Nader also be his 
worst votes against. So, with MDDA, Nader must not only be Dean's worst 
votes-against, but must also be only a vote short of a majority 

So MDDA is less likely to make the LO2E progressives regret voting Dean in 
2nd place instead of in 1st place with Nader.

Now, in MMPO's favor, from the point of view of someone who doesn't want the 
LO2E progressives to give away the election, when they vote Dean in 2nd 
place, instead of not voting a 2nd choice, that can't make Dean beat Nader.

There are a lot of issues relating to that advantage.

For one thing, it's only true when comparing voting Dean in 2nd place to not 
voting a 2nd choice. If the LO2E progressives vote Dean in 2nd place instead 
of strategically moving him down to 3rd place, or last place, that could 
allow him to beat Nader, where Nader would have won if they'd strategically 
downranked Dean. So really the LNH guarantee is only about a comparison of a 
limited subset of the ways that a person could vote.

When MDDA reduces the LO2E progressives' need to rank Dean in 1st place, 
that's reducing the likelihood that they'll give away the election and the 
likelihood that they'll conceal their Nader>Dean preference. But, given that 
they rank Dean 2nd, MMPO's guarantee that they won't give away the election 
compared to what would have happened if they'd not voted a 2nd choice--that 
guarantee only is that they won't give away the election when they already 
weren't concealing their Nader>Dean preference. And they're a little less 
likely to be willing to not equal-rank Dean in MMPO.

So we could make them more likely to rank Dean 2nd, when equal ranking him 
1st would conceal the preference and maybe give away the election; or we 
could let it be a little more likely they'd equal rank him, while, if they 
don't, prevent their 2nd ranking of Dean from giving away the election, 
compared to what would have happened if they'd not ranked a 2nd choice.

There's something a little questionable-sounding about the voting that LNH 
is about: Voting Dean in 2nd place instead of not voting a 2nd choice. As if 
not voting a 2nd choice were one of the things that the LO2E progressives 
were considering doing.

For all these reasons MDDA sounds better than MMPO.

I still liked MMPO because, even though it's wordier to define, being a 
MinMax method, it still has a unique kind of simplicity for a rank method. 
But the example that you posted seems to finish MMPO as a public proposal.

Mike Ossipoff

Don’t just search. Find. Check out the new MSN Search! 

More information about the Election-Methods mailing list