Methods of elimination in quota preferential STV

[LAYTON Craig]

Yes, you're all right.  People simply wouldn't go for it in the short term
(in the US, that is. As we already use a type of PR for some elections here,
the chances seem better).  The controversy isn't as significant as you might
think, though.  There is some consensus on the basics; 1) list systems are
bad.

This basically answers all the other problems, because multi winner systems
require districts to keep the number of candidates down.  You don't need
small party cutoffs 'cause districts with less than 10 seats/district will
make it difficult enough for them to win.  To ensure proportionality you
need at least 5 seats/district.

-----Original Message-----
From: Bart Ingles 

I don't know that anyone is advocating single-winner systems for
legislatures.  Speaking for myself, I am mainly interested in using
better single-winner systems wherever single-winner elections are held,
but I don't advocate them specifically for legislatures.  

I do give single-winner reform higher priority than multi-winner, for
several reasons:

1)  A single-winner system would still be needed for executive offices.

2)  If PR were adopted first, and gave rise to a true multi-party
system, then elections for executive office might be screwed up by the
spoiler effect even more than they are now.

3)  PR is a much more controversial concept than single-winner reform,
with more variables to be decided (e.g. what level of proportionality is
optimal?  Should there be a small party cutoff?  Districtless, or small
multi-seat districts?  List, or a multi-winner method such as STV?  And
so on...)  Single winner should be more 'doable', whereas focusing
primarily on PR might stall any reform indefinitely.

4)  If single-winner reform makes it possible for a true multi-party
system to begin to thrive and attract votes, money, and high-caliber
candidates, then there will naturally be support for more
proportionality in legislatures.

Bart




LAYTON Craig wrote:
> 
> While it is unarguably crucial to discuss the ideal single winner method
> (both simply in terms of the logic of majoritarian decision making on
> specific issues and in cases eg presidential elections, where only one
> winner is possible), are you all sure that you should be advocating any of
> these systems for the election of a legislature?
> 
> Perhaps in terms of political expediency, yes (but some aren't so
concerned
> with political expediency).
> 
> It doesn't seem that the accuracy of single winner systems have any
> relevance at all in a multi-member decision making body.  The overall
result
> is always fairly random, and depends more on electoral boundaries than
> anything else.  All reasonably good multi member systems (like Bart's
below,
> or David's, or Demorep's variable voting power, or standard quota
> preferential STV) will always produce a more accurate result than single
> winner, no matter how carefully derived the single winner system.
> 
> CVD gets alot of flack, but they do advocate PR wherever possible (and
only
> IRV where it seems that PR is too much of an uphill battle).
> 
> There is, I know, long standing prejudice against multi winner systems,
and
> there's always Federalism to contend with.  But, even in relation to the
> latter, it's important to note that even wildly differing electorate sizes
> will still produce better results than single winner systems (ie, make
each
> state an electorate with either 5, 7 or 9 members, depending on the
state's
> size.  The fact that some states are ten times larger than others won't
> affect the result as much as single winner electorates, and will keep the
> smaller states happy).  Of course, it has to be unicameral, which is
another
> change that is perhaps too radical to suggest.  Nevertheless, if you're
> after the best system.....
> 
> -----Original Message-----
> From: Bart Ingles [mailto:bartman at netgate.net]
> Sent: Thursday, 5 October 2000 15:20
> To: election-methods-list at eskimo.com
> Subject: Re: Methods of elimination in quota preferential STV
> 
> I haven't had time to think about multi-winner methods much, but I have
> been leaning toward a modified cumulative voting method with
> elimination.  I'm pretty sure the following method has been shown to
> violate monotonicity & participation (see below), but I suspect the
> violations may be less severe than STV's.
> 
> Voters simply vote for multiple candidates, as they would with approval
> voting, except that each choice gets an equal fraction of the vote (e.g.
> if you vote for five candidates, each gets 1/5 of your vote).  You then
> eliminate the weakest candidate and recount, so that the remaining
> candidates get a larger share (if one candidate was eliminated from your
> ballot, the remaining candidates now each get 1/4 of a vote).  Continue
> eliminating candidates in the same fashion until the required number
> remain.
> 
> No quotas are necessary since each voter always has the same cumulative
> vote.  The fact that voters must weigh compromise choices rather than
> simply rank them should yield higher overall utilities, and the method
> is certainly simpler than STV.
> 
> I have the following references regarding the method (I haven't seen
> them):
> 
> Bolger, E. M. (1983), "Proportional representation" in: S. J. Brams, W.
> F. Lucas and P. D. Straffin, Jr., eds., Modules in Applied Mathematics,
> Vol. 2 (Springer-Verlag, New York) 19-31.
> 
> Bolger, E. M. (1985), "Monotonicity and other paradoxes in some
> proportional representation schemes," SIAM Journal on Algebraic and
> Discrete Methods 6: 283-291.
> 
> -Bart