[EM] Re: Condorcet's strategy problem

MIKE OSSIPOFF nkklrp at hotmail.com
Thu Sep 15 18:23:33 PDT 2005


Rob--

You wrote:

I'd said:

>Nasty enough to make voters bury their favorite?
>
>Nope. That incentive will never exist withApproval or Range Voting.

You replied:

That wasn't what I was referring to.  Where do I draw the Approval
line?

I reply:

That's what makes Approval more fun.

You continued:

The strategy I've always heard for Approval is "vote for your favorite
frontrunner, and everyone you like better", with the assumption always
being that there's at most a couple frontrunners.  That becomes a
problem with a close three-way race.

I reply:

Sure, the Best-Frontrunner strategy is only for when there are two clear 
expected frontrunners. Then you could vote for your preferred one, and for 
everyone whom you like better. Or you could, vote for everyone better than 
the mean of those two expected frontrunners. The Best Frontrunner strategy 
has a number of versions, but those are probably the main two. I've 
discussed the other Best-Frontrunner versions in earlier postings.

Of those two Best-Frontrunner strategies that I named, it's better to vote 
for everyone who is better than the mean of the two expected fronrunners. 
The other strategy is good because it's simpler to offer to voters.

You continued:

If I like A, I hate B, but I
really hate C, do I risk approving B to make sure C doesn't get elected?
Sounds like I might end up back in the position of approving "the lesser
of two evils".

I reply:

No. Don't vote for an evil, in Approval or Pluarality. But you might well 
vote for a compromise, in addition to your favorite.

So what do you do when there aren't two obvious frontrunners?

First, it's usually obvious how you want to vote, without using any strategy 
method. The strategy methods are for when it isn't obvious.

If there's no obvious frontrunner, there are several other methods. Probably 
the main one is Better-Than-Expectation:

Vote for every candidate who is better than your perceived expectation in 
the election. In other words, vote for each candidate who is so good that 
you'd rather have him/her in office than hold the election.

Or, for each candidate, you could judge whether the threat of someone worse 
winning if you don't vote for him/her feels greater than the promise of 
someone better winning if you don't vote for him.
Which do you feel more like going by?

I call that Threat-Promise.

There are a few other strategy methods, similar to or related to 
Better-Than-Expectation and Threat-Promise.

You continued:

Over the long haul, with feedback from actual elections and learning
from the consequences of their decisions, we can hope that they would do
what is in their best interests.  Voting sincerely is going to be the
right strategy in the vast majority of cases.

I reply:

...unless you perceive an acceptable/unacceptable situation.

You continued:

If we assume that voters
are going to do stupid and counterintuitive things, then we should
probably rethink the whole idea of democracy.  Garbage in, garbage out.

I reply:

But you haven't shown that the way I would vote in a Condorcet election is 
stupid. Saying it isn't enough.

Why is it stupid to do whatever it takes to maximize the probability that an 
acceptable candidate will win, if the merit difference among the 
acceptables, and among the unacceptables, are negligible compared to the 
merit difference between the acceptables and the unacceptables. Under those 
conditions, what matters is that an acceptable wins, not _which_ acceptable 
wins. So you rank them in an order that maximizes the probability that one 
of them will win. That probably won't be sincere order.

Let's not sling namecalling around unless we can show that it's true.


I'd said:

>Please note that I myself like wv Condorcet, and that I advocate 
>BeatpathWinner or CSSD for committees and organizations, where there's no 
>really scary lesser-evil.

You replied:

I'm assuming that year five of the Bush administration has worn down
your resolve to push anything less-than-safe for public elections  ;-)
I can't blame you, but I still think Schulze(wv) is the best way to go.

I reply:

I voted for Nader in 2004. But I've noticed that at least some LO2E 
progressives will vote Kerry, and all the Democrats over Nader, though they 
prefere Nader. _That_ is what convinced me that a public voting system must 
meet FBC. BeatpathWinner is my favorite for committees and organizations, 
but its FBC failure makes it unsuitable for public political elections, at 
least under current conditions. Someday there may come a time when there are 
no winnable greater-evils, and no LO2E problem, and then SSD would become 
the best public political voting system, in my opinion.

SSD is a more naturally motivated and justified relative of BeatpathWinner. 
It gives the same results in public elections, with many voters.

You continued:

Let's take the worst case scenario with Schulze(wv).  You and other
Nader supporters decide to take the "safe" road, and rank lesser-evil
candidates (e.g. Kerry, Gore) above your favorite.

I reply:

Those are fighting words. :-) _No-one_ says that I'd vote for a Democrat. 
You can call my voting stupid, as you did in this posting, but don't ever 
say that I'd vote for Kerry or Dean. My voting isn't that stupid.

Yes, I'd favorite-bury, just as would the LO2E democrats, in order to 
maximize the probability that the winner will be an acceptable candidate. 
But I greatly differ with the LO2E progressives about what is acceptable. 
The Democrats are unacceptables, it seems to me.

But yes, many progressives would insincerely rank Kerry over Nader.

You continued:

That strategy is
every bit as safe, if not safer, than Approval, isn't it?

I reply:

My objection to people needing to do that is not that it isn't safe enough, 
or that it isn't as safe as Approval. My objection to it is that that voter 
is falsely saying that s/he likes Kerrry better than Nader. That voter is 
concealing their liking for Nader. That voter, in Condorcet, but not in 
Approval, is failing to show full support for Nader. That's what I object to 
in methods that fail FBC.

You continue:

If your goal is to avoid favorite betrayal at all costs, you're right,
Approval is best.

I reply:

RV and some rank methods meet FBC too. They'd be ok for public political 
elections too. But the rank methods aren't familiar or simple enough. RV 
wins by simplicity and familiarity.

You continue:

We'll have to agree to disagree, because that's not
my goal.

Ok, but when people are afraid to show full support for their favorite, 
"Democracy" becomes a joke.

You continued:

My main goal is to correctly find the candidate who would beat every
other candidate in a head-to-head election

I reply:

Good luck achieving that when people strategically need to vote someone over 
their favorite.
The first goal must be encouragement of at least relatively sincere voting. 
Electing a CW will often depend on that.

Mike Ossipoff

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