Various Condorcet Tie Breakers

DEMOREP1 at aol.com DEMOREP1 at aol.com
Fri Jun 14 00:35:57 PDT 1996


The single winner matrix below assumes that all the candidates are majority
acceptable-- that is, a majority zero vote has removed unacceptable
candidates and that any candidate(s) that lose all of their head to head
pairings have also been removed. 

In other words, each candidate has at least one head to head loss (which
produces the tie situation). 

On each ballot, the remaining candidates are in effect moved up on such
ballot to fill in the positions resulting from losing candidates.

Using relative rank order voting (1, 2, 3, etc.) produces an array (or
matrix). In the below the winner in a pairing is at the top and the loser is
at the left. Thus AB means the number of ballots that rank A over B. CT=
Column Totals, RT= Row Totals, GR= Grand Total
(View table in 9 point Monaco)
X  A   B   C   D   E   F   G    RT
A  X   BA  CA  DA  EA  FA  GA   ART
B  AB  X   CB  DB  EB  FB  GB   BRT
C  AC  BC  X   DC  EC  FC  GC   CRT
D  AD  BD  CD  X   ED  FD  GD   DRT
E  AE  BE  CE  DE  X   FE  GE   ERT
F  AF  BF  CF  DF  EF  X   GF   FRT
G  AG  BG  CG  DG  EG  FG  X    GRT

Thus, votes for a candidate are in the (vertical) columns and votes against a
candidate are in the (horizontal) rows.

Note that the simple two candidate case (A versus B) is in the upper left
corner.
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In the following, the potential for truncated voting should be noted. As I
have mentioned, a candidate who is ranked must be deemed to have a one vote
over each unranked candidate (since the matrix must collapse to a simple
plurality result if there is total truncation.) There is the major question
of the values for each candidate in pairs of unranked candidates- zero or
0.5.
------
Also to be noted is the fact that minority candidates may have been defeated
by majority zero votes. That is, the votes from minority voters might
definitely be cast for the lesser of evils (in their view). A majority
coalition might not be able to unite behind a candidate.
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A. Some somewhat obvious possible tie breakers--- 

1. The maximum votes for (the highest column total)
2. The minimum votes against (the lowest row total)
3. The highest net votes for minus votes against (the column total minus row
total that is the highest).
4. The candidate with the lowest zero votes (against the candidate).

B. Some not so obvious possible tie breakers--- 

1. Putting the net values of each XY minus YX pairing above (or below) the
diagonal. The absolute values of such net values (i.e. dropping the minus
signs) would be arranged in order.
High net values (such as 66 - 34 = 32) indicate that the candidate defeated
has some major relative unacceptability (i.e. the minority may unite against
such a candidate). 
Low net values (such as 52 - 48 = 4) indicate that the winner might be a
compromise.

2. Redoing the matrix based on fewer choice levels (such as the first and
second choices only and adding choice levels, if necessary) (or dropping the
lowest choice level on all ballots- and additional choice levels, if
necessary).

3. Changing each choice level to a vote and summing the minimum number of
choice levels to get the highest majority (i.e. limited approval voting).

4. The worst defeats on each row are noted. Among such defeats the one with
the least votes against would determine the winner.

5. Dropping the candidate with the lowest number of wins, one by one. 
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Any more ideas for tie breakers ?




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