Why the unrealistic example is unrealistic:
40A
35C>B
30B
This example is not realistic because it is extremely unlikely that all the supporters of one party would express a second preference whilst none of the supporters of the two other parties would.
Why this example is not that unrealistic:
49 A>B>C
3 B>A>C
48 C>B>A
Bedfordshire South-West
British General Election 2001
Conservative 42.1%
Liberal Democrat 14.8%
Labour 40.4%
Other 2.7%
In every British general election since Feb 1974 you could probably find approximately 100 similar results ( out of 635- 659 constituencies).
Adam Tarr quoted me as stating in response to:
40A
35C>B
30B
"IRV succeeds, I believe, in striking a balance between the two somewhat conflicting aims of ensuring that a candidate has majority support ( a candidate does not win with a minority of the vote because the opposition is split) "
You appear to have quoted only part of the sentence and in doing so have altered its meaning
IRV succeeds, I believe, in striking a balance between the two somewhat conflicting aims of ensuring that a candidate has majority support ( a candidate does not win with a minority of the vote because the opposition is split) and preventing dominance by candidates/parties who position themselves in the centre.
If you consider the example
10% FarRight>Right>Centrist>Left>FarLeft
10% Right>FarRight>Centrist>Left>FarLeft
15% Right>Centrist>FarRight>Left>FarLeft
16% Centrist>Right>Left>FarRight>FarLeft
15% Centrist>Left>Right>FarLeft>FarRight
13% Left>Centrist>FarLeft>Right>FarRight
11% Left>FarLeft>Centrist>Right>FarRight
10% FarLeft>Left>Centrist>Right>FarRight
Considering the electorate as 3 factions- Right 35%, Centre 31%, Left 34% IRV is doing exactly what I want it to do - preventing Centrist dominance.
Under Condorcet the only way the Right or Left factions could win is if they obtained 50%+ of the first preference vote. I am prepared to live with the possibility of your example if it prevents Right 42%, Centre 17%, Left 41% with the Centre winning.
David Gamble
