[EM] Anyone got a good analysis on limitations of approval andrange voting?

[Michael Allan]

Terry and Matthew,

Terry Bouricius wrote:
> I'm not sure if it is quite at the layman level, but Prof. Nicloaus 
> Tideman's recent book "Collective Decisions and Voting" has an analysis of 
> vulnerability to strategic manipulation of virtually every single-winner 
> voting method that has ever been proposed...

He leaves out the methods that facilitate communication among the
voters, namely liquid democracy, delegable proxy or delegate cascade.
These are all forms of continuous, peer-to-peer voting.  Their overall
are difficult to manipulate, except by force of reason.  (This assumes
that all votes/voters are public.)

These methods are not proof against micro-strategy by individual
voters, but their combined effects cannot significantly sway the
overall results (not in theory, anyway).

> A somewhat more accessible (and available online for free) analysis of 
> strategic vulnerability of various methods is in this doctoral paper by 
> James Green-Armytage ("Strategic voting and Strategic Nomination: 
> Comparing seven election methods"). He found that Range and Approval were 
> just about the worst in terms of manipulability.
> http://econ.ucsb.edu/graduate/PhDResearch/electionstrategy10b.pdf

He makes the same omission, at least in that paper.  Please, does
anyone know where Green-Armytage analyzes his "liquid democracy" from
the angle of strategic voting?

Matthew Welland wrote:
> It seems to me that approval and range voting eliminate most of the
> strategic opportunity in single winner elections and the marginal
> improvement of other methods is fairly small. Can anyone point me to
> analysis, preferably at a layman level, that contradicts or supports this
> assertion?
> 
> Or, in succinct terms, what are the strategic flaws in approval or range
> voting?

In that they encourage voters to be manipulative.  In terms of action
theory, these voting methods (and almost all others) are tools of
strategic action.  The voter uses them in an attempt to attain a
preconceived end.  So they are tools of *teleological* action.

But to attain the preconceived end, the voter must calculate on the
behaviour of other voters.  This introduces a social aspect to the
action, which is therefore subclassed as *strategic* action.

The only alternative in this context is *communicative* action.  In
communicative action, the voters coordinate their voting behaviour by
discussion that is aimed at mutual understanding and consensus.
Ordinary voting methods do not support this.^[2]  For this you need a
communicative method, such as continuous, peer-to-peer voting (top).

[1] I'm not sure that the terminology aligns perfectly with voting
    theory.  Action theory is from sociology:

    Jürgen Habermas.  1981.  The Theory of Communicative Action.
    Volume 1.  Reason and Rationalization of Society.  Translated by
    Thomas McCarthy, 1984.  Beacon Hill, Boston.  pp. 75-101.

[2] Not only do these voting methods not support communicative action,
    but they serve as substitutes for it.  They are therefore defined
    as "steering media".  The archetypal steering medium is money,
    which serves as a substitute for inter-communicative bartering.
    [ref. Vol. 2 of above]

-- 
Michael Allan

Toronto, 647-436-4521
Skype michael_c_allan
http://zelea.com/