Fixing IRV
DEMOREP1 at aol.com
DEMOREP1 at aol.com
Mon Aug 13 16:17:03 PDT 2001
Forest wrote
The following example has dampened my enthusiasm for Roy's IRV fix based
on eliminating the candidate with the lowest median rank:
13 ABCXD
13 BCDXA
13 CDAXB
13 DABXC
16 XABCD
16 XBCDA
16 XCDAB
100
Note that X is both the Condorcet Winner and the candidate with the lowest
median rank

D Doing some place votes math
  1 2 3 4 5
1 13 A B C X D
2 13 B C D X A
3 13 C D A X B
4 13 D A B X C
5 16 X A B C D
6 16 X B C D A
7 16 X C D A B
Grouping the votes
 1 2 3 4 5 TOT
A 13 29 13 16 29 100
B 13 29 29 0 29 100
C 13 29 29 16 13 100
D 13 13 29 16 29 100
X 48 0 0 52 0 100
Combining 1+2 and 4+5 

1+2 3 4+5 TOT
A 42 13 45 100
B 42 29 29 100
C 42 29 29 100
D 26 29 45 100
X 48 0 52 100
(1+2)(4+5)
A 3
B 13
C 13
D 19
X 4
0
I have mentioned many times that a YES/NO vote should be done.
The above Forest example is an excellent reason to do so.
IF (repeat, IF) a 4th or 5th place vote was a NO vote, then X would lose
(even though X is a Condorcet Winner).
How many *near* clones are in the example  especially A>B, B>C, C>D, D>A
???
I note again that it may be difficult to tell where *near* clones come from.
N1 X > Y
N2 Y > X
Z comes along
Possible 
NIA Z > X > Y
N1B X > Z > Y
N1C X > Y > Z
N1
N2A Z > Y > X
N2B Y > Z > X
N2C Y > X > Z
N2
Whether Z is an opposite or a clone *leader* may be difficult to detect
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