# [EM] Chris: Approval

Michael Ossipoff mikeo2106 at msn.com
Mon Mar 19 06:53:30 PDT 2007

```I'd said:

>>Obviously majority rule is violated by an outcome that is contrary to what
>>a majority have voted that they want. For instance, if a majority vote B
>>over A, then we can assume that, if A or B wins, they vote that it be B.

Chris says:

>That is reasonable, and granted for the sake of argument. That implies that
>you agree with Kevin Venzke that Minimal Defense(MD) must be met

It does?? I don't agree with Keviln Venzke that Minimal Defense (MD) must be
met.

We've discussed this before. I have never advocated Minimal Defense.It's
completely different from SDSC, on which it's based.

But I don’t even say that SDSC must be met. Approval doesn’t meet SDSC. I do
say that there’s no point proposing a rank method without SFC and SDSC.

Chris continues:

>no-matter-what, but while I think MD compliance can be a positive for an
>otherwise bad method I think the best methods can do without it.

Maybe, but if you do without SFC & SDSC, you're doing without the strategy
guarantees that justify using rank balloting.

>
>49: A
>24: B
>27: C|B
>
>MD says "not A", but A is the only candidate in the Definite Majority set.
>(C knocks out B, and A knocks out C).

Ah well, that settles it, if the definite majority set says so. :-)

A majority say that, if it's B or A, it should be B. That means don't elect
A. A is the only candidate with a majority against him.

>
[after a discussion of what majority rule means for single-winner outcoms]

>That opens up the question of how best to measure the strength of pairwise
>defeats. Alternative algorithms for DMC are Beatpath(Total Approval),
>River(TA), Ranked Pairs(TA) which all measure the strength of a pairwise
>defeat by the approval score of the pairwise winner.

Fine, measure defeat-strength that way if it results in a guarantee that's
important to you.

DAMC measures strength in that way, but looks only at majority defeats, and
does alright. But TA by itself won't do nearly as well.

>At least in the "three candidates in the top cycle" situation, an
>alternative algorithm for ASM is Approval Margins that uses one of
>River,BP,RP
>and measures pairwise defeat strengths by the difference between the
>approval scores of the two candidates. Both DMC and ASM meet the
>Definite Majority criterion.

No doubt that criterion may be important to you.

[After an example]

>Here {A} is not just the Definite Majority set but also the "Definite
>Absolute Majority" set

No shit! <smiley> Again, defining those sets doesn’t make them official
standard.
If you want to say that they’re important, then you need to tell exactly
why. Just citing them like some kind of authority doesn’t mean anything.

>(which doesn't conflict with MD),
>so I can't see how anyone can credibly claim that electing A here flouts
>"majority rule".

Forgive me for being unfashionable, but a majority have indicated that if
it's B or A, it should be B.
That B>A majority defeat isn't nullified by being in a cycle of defeats at
least equally strong.

Yes, you or someone have made up a "definilte majority set" and a "definite
absolute majority set", but you must understand that that does not mean that
they automatically become the definitive standard.

>>I haven’t given any consideration to what methods pass or fail the
>>Majority Rule Criterion, but:
>>
>>Plurality, Approval, -1,0,1 are among the methods that pass.
>
>
>You are repeating your old trick of claiming that methods like Approval and
>FPP meet criteria just because they use barbarically
>restrictive ballots.

notice that I said that I won't be using the Majority Rule Criterion. I in
no way implied that Pluralty and Approval have merit because of passing
Majority Rule. You proposed it as a criterion (yes, by a different name) and
I merely stated some methods that pass, without saying that it means that
they have merit.

But you're repeating your old trick of being vague. You don't specify any
other instances of my claiming that methods like FPP & Approval meet
criteria because they use barbarically restrictive ballots.

If a method meets a criterion, and it's a desirable criterion, then _why_
the method meets that criterion is irrelevant, with regard to the statement
that the method meets the criterion, and the benefit of meeting that
criterion. The criterion's benefits are available to voters using that
method if it meets the critrerion. Does Approval meet desirable criteria
because of its simplicity? Sure.

"Barbarically restrictive" is a meaningless expression, except as an
expression of strong emotion.
You could complain about Approval "taking away" the expressiveness that
ranking gives, if you could show that ranking is necessary and fundamental.
Fundamental? There isn't even any agreement about how rankings are most
fairly counted. Some fundamental standard for that is.

Rankings can be useful, depending on how they're counted. But it's
ridiculous to say that they're fundamental and necessary, so that it would
be barbaric to take them away.

There _is_ something fundamental about Approval. As I said, it's the minimal
method that allows the voter to say something about each candidate. Most
rank methods' only achievement is losing Approval's advantages. Like a
laborsaving atuomatic machine, a rank method can be helpful, or it can be
worse than no rank method. If you want to improve on Approval, be careful,
or you’ll just make a mess.

I'm not exactly a pioneer in stating that Plurality meets criteria that have
some acceptance here.
Participation, votes-only IIAC, Consistency, etc.  Plurality meets those
criteria too. So what?

>You base your version of the Condorcet Criterion on voters' sincere
>preferences, but for some reason this criterion [Majority Rule Criterion,
>which I didn't state as a criterion]
>has to be purely about cast votes even with a restricted ballot.

For some reason? Majority rule isn't a defensive strategy criterion. It
speaks of the effectiveness of a majority's cast ballots. That should be
obvious, and my definition merely reflects what is obvious.

>I share the Venke (similar to Woodall's) approach that the criteria
>should assume that the voters intend to submit a ranked ballot (maybe
>truncated, maybe with some equal-ranking) and that voters
>fill out their actual (maybe restricted) ballots in a way that is
>consistent with their intended ballots, and when ballot restrictions
>prevent
>voters from fully voting their intended ranked ballots the criteria are
>based on the intended ballots.

What an elaborate counterfactual story. It’s amazing what lengths to which
some people will go,  to make Plurality fail Condorcet’s Criterion without
mentioning preference.

system. My criteria make no mention of any balloting system.

Though you go to great lengths to avoid mentioning preferences, you don't
mind saying that the voter intends to vote a ranking, when s/he votes in
Plurality. I've talked to voters, and many of them are adamantly opposed to
any voting system other than Plurality. They don't intend to vote a ranking
when they vote Plurality. And that's only part of the counterfactual nature
of your fictitious-rankings system of criteria.

Could you demonstrate why Approval and 0-10 CR fail Condorcet’s Criterion,

Aside from that, why is it ok to speak of intent, but not preference?

>
>The suggestion that methods that meet Majority for Solid Coalitions and
>Schwartz and Definite Majority are somehow worse at
>giving effect to "majority rule" than methods that fail Majority Loser is
>ridiculous.

That depends on what you think majority rule means, in the context of
single-winner outcomes.
Also, you’re vaguely spouting out a list of types of methods that I haven’t
evaluated with respect to majority rule violation.

>>You’re referring to the 0-info situation.
>>
>>With zero-info, with voters using the 0-info strategy of voting for the
>>above-mean candidates, Approval will elect the candidate who is above-mean
>>for the most voters. That is much.
>
>Much what?

Much merit. Much fairness. Exactly what do you want “much” of, when we
choose the candidate who is above mean for the most voters? Or, more
generally, the candidate who is acceptable to the most voters?
The desirability of that choice is very “much” obvious.

Chris continues:

[after naming a long list of criteria met by Approval]

>But it fails Majority Favourite and Majority Loser

Do you mean those criteria with your fictitious rankings?

I’ve never denied that rank methods can add advantages not available in
Approval. I’ve even said that I myself would prefer a good rank method for
our public elections, though I myself, as a voter, would be content with
Approval. It would be a nice luxury to rank the best candidates, but I don’t
really care which one of the best candidates wins.

Chris continues:

>and is very vulnerable to disinformation campaigns

That’s a vague statement that could be said of many methods, including some
that Chris likes.

Chris continues:

>and has nasty defection/truncation
>incentives.

I’ve answered that one many times on EM. I should keep a FAQ of answers like
that, and periodically post it. I could search the archives to find one of
those instances where I answered that, and hen copy and paste it here, or
link o it. But maybe I’ll just comment on a few aspects that occur to me
now.

First, as I said, I don’t care which of the best candidates wins. So if
supporters of one of the best candidates want their one favorite to win so
badly that they defect,, so what? If they want it that badly, let them have
it.
Anyway, if the defection were strongly disliked or resented, then the
the voters on the other end of the defection.

The scenario you’re referring to involves (say) two candidates whose
supporters prefer both to some other candidate(s). As I said, if you vote
for both, then they’re both acceptable to you. So how bad can it be if your

If your point is that rank methods can be more deluxe, no one is denying
that. You can’t have everything in one method.

Usually one of those  2 candidates will have more support than the other, or
be better positioned as a compromise. Or have a better moral position. That
candidate’s voters can make it clear that they’re going to bullet vote.

If the 2 candidates are so similar that the above conditions aren’t true,
then, especially, does it really make any difference which one wins?

In summary, the situation is not “nasty”, as you claim it to be. Approval
opponents always exaggerate that problem.

Approval isn’t the only method to have that problem. It’s misleading to
portray it as an Approval problem.
WV Condorcet has it too. No doubt a number of other rank methods have it
too. IRV doesn’t. But you  gain one advantage by giving up another.

Sincere preferences:

40: A
29: BC
31: CB

The C voters vote C & B. The B voters vote only B. B wins by defection.

Chris, can you find a majority who is being robbed of victory here?

A majority-size group is a group to whom various guarantees can be made. A
majority can always get its way, but we’d like to guarantee that they
needn’t do  drastic giveaway to get their way. But the C voters are not a
majority, and it’s more difficult to make guarantees to them.

Yes C is the CW, but no one claims that Approval is a Condorcet method.

Mike Ossipoff

```