[EM] Looking for a little voting insight...

[Markus Schulze]

Dear Matthew Welland,

you wrote (30 April 2006):

> Rubyvote has pure condorcet and cloneproof schwartz
> sequential available. 

At Wikipedia, "pure Condorcet" is called "Minimax
Condorcet":

http://en.wikipedia.org/wiki/Minimax_Condorcet

At Wikipedia, "cloneproof Schwartz sequential dropping"
is called "Schulze method":

http://en.wikipedia.org/wiki/Schulze_method

******************************************

You wrote (30 April 2006):

> I want to keep things simple.
> Does it matter which method I choose?

Yes, it does matter. Minimax and Schulze are different
methods.

Example:

   3   A > B > D > C
   5   A > D > B > C
   1   A > D > C > B
   2   B > A > D > C
   2   B > D > C > A
   4   C > A > B > D
   6   C > B > A > D
   2   D > B > C > A
   5   D > C > A > B

   Suppose d[X,Y] is the number of voters who strictly
   prefer candidate X to candidate Y. Then we get:

   d[A,B]=18
   d[A,C]=11
   d[A,D]=21

   d[B,A]=12
   d[B,C]=14
   d[B,D]=17

   d[C,A]=19
   d[C,B]=16
   d[C,D]=10

   d[D,A]=9
   d[D,B]=13
   d[D,C]=20

   Minimax chooses candidate B.

   The strongest paths are:

   A-18-B
   A-21-D-20-C
   A-21-D

   B-17-D-20-C-19-A
   B-17-D-20-C
   B-17-D

   C-19-A
   C-19-A-18-B
   C-19-A-21-D

   D-20-C-19-A
   D-20-C-19-A-18-B
   D-20-C

   Schulze chooses candidate A.

Markus Schulze