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

[Jobst Heitzig]

Dear Kristofer,

both Approval Voting and Range Voting *are* majoritarian: A majority can always get their will and suppress the minority by simply bullet-voting.

So, a more interesting version of your question could be: Which *democratic* method (that does not allow any sub-group to suppress the rest) has (usually or on average or in the worst case) the least Bayesian Regret. 

I conjecture that at least when the nomination of additional options is allowed, the method SEC described recently is a hot candidate for this award, since it seems that SEC will lead to the election of the option at the *mean* (instead of the median) voter position, and I guess that in most spacial utility models the mean position is in many senses "better" and will in particular have less Bayesian Regret than the median position. (Recall that in a one-dimensional spacial model where additional options can be nominated, all majoritarian methods likely lead to median positions being realized and are thus basically all equivalent.)

Yours, Jobst

 
> -----Ursprüngliche Nachricht-----
> Von: "Kristofer Munsterhjelm" <km-elmet at broadpark.no>
> Gesendet: 08.11.09 10:23:11
> An: Warren Smith <warren.wds at gmail.com>
> CC: election-methods <election-methods at electorama.com>
> Betreff: Re: [EM] Anyone got a good analysis on limitations of approval and range voting?


> Warren Smith 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?
> >> Thanks, Matthew Welland
> > 
> > --well... there is the whole rangevoting.org website...
> > my more-recent papers at
> > math.temple.edu/~wds/homepage/works.html
> > discuss range voting including some ways it is provably better than every
> > rank-order voting system for either honest or strategic voters...
> > 
> > --but those are not exactly "succinct"...
> > 
> > OK Let me try:
> > 1. Range for 100% honest voters behaves better than IRV, Borda,
> > Condorcet and it is pretty intuitively clear why -- strength of
> > preference info used, not discarded.
> 
> There is, of course, the flipside of that property. If one wants a 
> voting method where the majority wins, then Range won't work, simply 
> because a minority of strong opinions can outweigh a majority of weak 
> ones. You might argue that that is no bug at all (strong opinions 
> *should* outweigh weak ones), but for those for which Majority 
> compliance is a must-have, it should be mentioned - particularly since 
> that is supposed to be one aspect of the fairness of traditional democracy.
> 
> In that sense, moving to Range (and perhaps Approval - depends on how 
> you interpret it) is a more radical proposal than, for instance, moving 
> to Condorcet (which passes Majority).
> 
> (And now I wonder which election method that passes Majority has the 
> least Bayesian regret.)
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