[EM] Re: Chris: Approval vs IRV

[Chris Benham]

Kevin,
I  had written (Th. June 10):

This from a post dated  Fri.Dec.4, 1998  ("IRO" means IRV, and  "VA" 
stands for "Votes Against" and refers to Condorcet,Winning Votes.
"PR" means Proportional Representation. AL is the Australian Albert Langer.)

> [AL]
> In Australia IRO makes the support for third parties highly visible.
> NOBODY who would vote for them under Approval or VA fails to vote for
> them as a result of strategic considerations concerning IRO.
> Nevertheless, since they never win any seats they don't get to build
> their support in the way that they would if they were represented.
>
> Of course they wouldn't dominate a PR Parliament either. They would
> simply be represented, which is all that PR supporters have ever claimed
> for PR. As a result of being represented they might build their support,
> so the two party monopoly makes damn sure they aren't.
>
> <snip>
>
> [MO]
> With IRO something _does_ prevent people from registering their support
> for a less winnable alternative: The fact that while their vote is
> on their favorite, a needed compromise might get eliminated, resulting
> in the victory of one's most despised last choice.
>
> [AL]
> Nope. That is just your speculation. Ask any Australian of any political
> persuasion and you'll find that this just isn't a factor in the way
> people actually vote here (as opposed to the way parties plan their
> campaigns). <snip>

To which you replied:

>I think that parenthetical bit is important, since I claim nomination disincentive
>is IRV's biggest problem (and also that of FPP, cumulative voting, DAC/DSC...).


CB:I can't say that there is any significant evidence of that in Australia.
In Australia, most voters don't know or care who the individual candidate is. They usually just decide 
which party they're going to support, and then fill out their ballots as that party reccomends. In some 
seats a major party will have a big majority, and so the election itself seems like a formality. The 
major parties are not run particularly democratically, so the decision of who gets endorsed for a given 
"safe seat" is sometimes made by party bureacrats on criteria other than merit or local popularity. 
Sometimes they go too far, and try to impose a candidate that the local branch and/or the local electors 
don't like. In that case, an independent who identifies as a supporter of the major party (whose "safe" 
seat it is) will sometimes run ("directing preferences" to that party), and win the seat (sometimes with
the help of the preferences of the other major party). The threat of this happening puts some limit on 
the power of major party machines to just give out these seats to whoever they like. Under Approval, I 
don't think that this would work as well.

In an earlier post (Sun.Jun.6) you wrote:


>This is a tired scenario, but consider this while thinking of "half-clones":
>40 A
>35 C>B
>25 B
>
>I call {BC} a half-clone set.  In Approval the C>B voters can vote CB and still get
>B to win, and this doesn't involve any insincerity.  In IRV those voters should put
>C below B in order to avoid electing A.  Not only does IRV encourage insincere
>voting here, but the fact that it does so will be a strong incentive for C not to
>enter the race at all.

CB: In some states in Australia, truncation is allowed; but not in national ("Federal")elections.
So until some years ago, C would win in your scenario because all the votes for A and B would be
binned as "invalid". Now where truncation is not allowed the (absurd) law is as follows.
Voters are obliged to number every candidate, and it is illegal to advise anyone to do otherwise.
Each candidate registers a "ticket" with the electoral commission before the election, giving a
full ranking, but this ticket can be "split" (with some equal ranking). I'm pretty sure that if the
voter numbers all but one, that is fine. If the voter numbers more than one, but leaves hir full
ranking ambiguous, then that is an invalid vote. But if the voter numbers one candidate only (with
a [1]), then that is interpreted as a vote for that candidate's ticket! (which the voter probably
knows nothing about).
So something like your scenario would only be possible if A and B both submitted "split tickets",
in which case C and A would each get half B's second preferences, and A would win.

But all that aside,I think that any "disincentive to run" with IRV is absolutely negligible compared
to Plurality, and on balance probably less than with Approval. With Approval, a new candidate/party
running for the first time has to either say to the voters "I'm a sure loser, so vote for me and one
of the the candidates who isn't" or "Vote for me alone in first place and split the (anti-X)vote".

You wrote (beginning with quoting me):

>>  From the point-of-view of voters that aren't interested in 
>> strategising, Approval doesn't "guarantee" anything.
>
>I don't follow here.  Order-reversal never helps in Approval.  That isn't a 
>valuable guarantee to a sincere voter?


CB:I had in mind the "one big guarantee" that voters are "never strategically forced" to downrank
their favourite (use the Compromise strategy) that Mike O. trumpets. 
Ok, in theory a sincere voter could be disadvantaged, but in practice, voters who are not interested
in strategising are usually not interested in strategy. If after an IRV election in which some voters
successfully Compromised, you wanted to demonstrate to some sincere voters that they had been
disadvantaged, you would show them the ballots and say....what??

You wrote:

>I can't picture these voters, who just want to vote sincerely, and think IRV
>has better guarantees than Approval.  I would think that valuable guarantees
>would have to be something about the way a sincere vote will be counted.  If
>you're just voting sincerely in IRV, without any direction from a party, you 
>couldn't expect that you would be able to take advantage of Majority, for
>instance.

CB:I would think that voters who just want to vote sincerely, wouldn't even understand Approval's
"guarantees", let alone appreciate them. I can't see any sense in your last sentence. Usually it is 
easily predictable which two candidates will make the final runoff, so if you have a preference between 
them, you rank the preferred one over the other.
Also Majority (for solid coalitions, aka Mutual Majority) is not really something that is there for
individual voters "to take advantage of". It is a criterion that is about the fairness of the result.


Chris Benham
















 

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