[Election-Methods] Improved Approval Runoff

[Diego Renato]

2007/8/16, Abd ul-Rahman Lomax:

> At 04:00 PM 8/15/2007, Diego Renato wrote:
> >All one-round voting systems that allows ballot truncation are
> >vulnerable to bullet voting, resulting the same results of plurality
> voting.
>
> "Vulnerable" implies that there is something wrong with this. It is
> not correct to claim that this gives "the same results" as plurality
> voting. That's only true if *all* voters bullet vote. And if that is
> what they want to do, who are we to say that they should not?
>

Read my previous message. If the majority of voters really intend to vote
for one candidate, they still are able to do it under IAR.

>  For instance, suppose that some voter has A as his/her first
> > preference. S/he can vote like this:
> >
> >Approval: A: approved; B: rejected; C: rejected; D: rejected ...
> >Range (0 - 100 scale): A: 100; B: 0; C: 0; D: 0 ...
> >Preferential (IRV, Condorcet, etc): A>B=C=D=...
>
> Yes. What's the problem? In a good method, if truncation results in
> no majority winner, that is, majority consent to the win is not
> apparent from the ballots, there should be a runoff.
>
> >Additionally, there are several instances which only binary input
> >voting systems are reasonable. Complex systems are hard to adopt in
> >low-educated underdeveloped countries.
> >
> >This system, called Improved Approval Runoff (IAR), has the goal to
> >resist bullet voting through simple ballots.
>
> I'm mystified as to why we should "resist" bullet-voting.


We should resist TACTICAL bullet voting for the same reason that many other
methods than plurality. Increase the overall satisfaction of the voters.

>Description:
> >
> >1) On the first round, the voter can vote for as many or as few
> >candidates as desired.
> >2) If some candidate has more than 50% of approvals, the most
> >approved is elected.
> >3) If not, that candidate runs a second round against other
> >candidate - the most approved after a new count which the votes for
> >the first one are reweighted to 1/2.
> >4) The winner is the candidate who receives a majority of votes on
> >the second round.
>
> It seems with the reweighting that it is assumed that the voter only
> votes for two, otherwise why that particular reweighting?
>
> I'm not sure I understand the "second round." The expression was a
> bit garbled, I suspect. I assume that the "second round" is not an
> actual runoff, but a recounting. As written, it would seem manifestly
> unfair to the first candidate, the plurality winner of the approval
> election.


It is a runoff. The weight of 1/2 fo the second round of count after first
election is based on Sequential Proportional Approval Voting. The contenders
of second runoff are the same winners of an hypotetical two-winner election
under SPAV. This approach increases chances of a consensus candidate be
selected to compete in runoff.

An example with four candidates: Bush, Bush clone, Gore and Nader. Bush
clone is a candidate strategically nominated:

2: Bush >> Bush clone > Gore > Nader
45: Bush = Bush clone >> Gore > Nader
27: Gore > Nader >> Bush = Bush clone (honest); Gore >> Nader > Bush = Bush
clone (strategic)
26: Nader > Gore >> Bush = Bush clone (honest);  Nader >> Gore > Bush = Bush
clone (strategic)

If under top-two approval, Bush and Bush clone will run the runoff election.
Under IAR, Bush and Gore will run.

1st count (1st round):
47 Bush <- selected for runoff
45 Bush clone
27 Gore
26 Nader

2nd count (1st round):
22,5 Bush clone
27 Gore
26 Nader<- selected for runoff.

Final result (runoff)
47 Bush
53 Gore (winner)

There is no way to guarantee that a candidate gets "the majority of
> votes" except by redefining votes to mean something other than "the
> majority of voters approve this outcome of the election." (Top two
> runoff does it by a trick: the voters only have two choices, and any
> ballot which does not select one of them is discarded. This is
> actually a failure of democracy, election results, when possible,
> should always be ratified by a majority. That's what happens in small
> societies using full democratic process, this step is only skipped in
> large elections, supposedly for efficiency.
>
> However, Asset Voting methods could make real runoffs and
> ratifications quite efficient.
>
> >On computer simulations, the top-two approval runoff method selected
> >more times the Condorcet winner than any Condorcet method. I think
> >that IAR is slightly fairer than top-two approval runoff under real
> voters.
>
> Again, I don't think that's true. Approval is *not* guaranteed to
> pick the Condorcet winner, no matter how you slice it, and any
> Condorcet method, by definition, will. That is, a Condorcet method
> *always* finds the Condorcet winner if voters vote sincerely, and
> there are few reasons to treat the matter as if they will not.
>
> however, the Condorcet winner is not necessarily the best winner;
> Approval may, indeed, select a better winner, as shown by social
> utility simulations. Approval begins the progression of Range
> methods, which match the very method of measuring what it means to
> have a good result. ("Condorcet Criterion" can be shown to manifestly
> make a poor choice under certain conditions, it really is not
> controversial. That is, a small society would *never* choose what the
> Condorcet Criterion would indicate should win, given sufficient
> knowledge, under certain conditions, basically those of a majority
> with a sufficiently weak preference and a minority with a
> sufficiently strong one. Who decides, properly, when such a condition
> should result in the violation fo the Majority Criterion?
>
> The majority, but it is crucial that the decision be explicit.
>
> What I have suggested is that Approval have a preference marker
> added. I called this A+; that is, Approval with a "Plus" indicator
> that shows preference. This marker could be used for more than one,
> but the general intention is that it would be used to show the
> Favorite. The ballot then indicates the set of approved candidates --
> these are considered acceptable under the present conditions by the
> voter -- and the favorite -- or favorites -- as well.
>
> However, initially the ballots are counted without regard to the Plus
> marker. It's an Approval election, initially. Now, with basic A+,
> that's it. The Plus marker is used for analysis of election results,
> allocation of campaign funding, and other informational purposes.
>
> But having this preference information allows a new possibility, I
> called it A+/PW, for Approval Plus, Pairwise. If the ballots show
> that there is a *different* winner through pairwise analysis, using
> the Plus markers as well as the other Approval Votes, then there
> would be a runoff election between the Approval winner and the
> most-approved candidate who beats the Approval winner.
>
> This version of Approval is Majority Criterion compliant, but through
> a trick: it's the majority in the runoff that counts. Nevertheless,
> this is far more democratic. It is much closer to an explicit
> ratification of the election.
>
> I would also trigger a runoff if there were no candidate with
> majority Approval. If there was no candidate who beat the Approval
> winner pairwise, the runoff could be between the top two Approval
> candidates.
>
> But Asset Voting is better.... And the Asset Ballot is extremely
> simple; it is a basic Approval ballot.


I'm not well informed about Asset Voting, but in Brazil, where two-round
elections are performed for single-winner elections, there are negotiations
among candidates for influence the support of the voters during the second
round. Frequently voters do not vote for the supported candidate of their
first round favorite.

________________________________
Diego Santos
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