[EM] Re: Testing 1 2 3

Dgamble997 at aol.com Dgamble997 at aol.com
Mon Jan 12 14:09:02 PST 2004

Forrest Simmons wrote in part:

>More to the point of this thread (Testing 1,2,3) if we are going to
>compare various methods, some of which are based on CR ballots and some of
>which are based on ranked preference ballots, the simulations need some
>common denominator.  Since it is easy to convert CR ballots to ranked
>ballots, and problematic to go from ranked to CR, it would seem more
>natural to use CR ballots as the common denominator.

This sounds like quite a good idea. I do see one or two potential problems 
with it though:

1/ How from a CR ballot do you determine the ranked ballot truncation point ( 
the level of utility at which voters cease ranking candidates).

2/ Lack of real world comparison data. I adjusted the votegenerator part of 
the spreadsheet as a result of looking at the data sets it was producing and 
comparing them with the South Australia state election of 1997 ( 3 parties- 
Liberal/National, Labor and Australian Democrat made a reasonable showing ) and 
the Queensland state election of 1998 ( Liberal/National, Labor and One Nation). 
The distribution of second preferences in the votegenerator data sets was 
much more variable than those in real elections and votegenerator was adjusted as 
a result of this.

I know that you've made several posts on the subject of converting CR ballots 
into Approval ballots could you tell me where they are?

>If the ballots were used for MAM, RP, SSD, IRV, etc. it wouldn't make any
>instrumental difference if you used the evenly spaced ratings or the
>adjusted ratings, but the satisfaction of increased expressivity is not to
>be sneezed at.

Just a quick point, comparing different 'flavours' of Condorcet is actually 
very boring as Condorcet cycles are fairly rare unless you produce data sets 
based on unrealistic preferences within the electorate for example:

A =35  B =35  C =30

A = 5  A>B=90  A>C= 5   B =5   B>A = 5  B>C = 90  C = 5 C>A = 90  C>B = 5

This would generate a data set based on party A  supporters preferring party 
B to party C, party B supporters preferring party C to party A and party C 
supporters preferring party A to party B. Circular preferences within the 

David Gamble

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