[EM] CRCLE Response to Donald

[Dgamble997 at aol.com]

Donald wrote in response to the example:

> 49 A>B
> 3B
> 48 C>B

>For B to win in this situation she/he must have a minimum utility of 0.92 to 
A>B >voters and a minimum utility of 0.96 to C>B voters. To win B has to be 
highly liked >(approved?) by everybody.

>  49 A1.00 > B0.92
>  3 B1.00
>  48 C1.00 > B0.96

>A versus B     49 v 49.08  B wins
>A versus C     49 v 48      A wins
>B versus C     48.08 v 48  B wins

>C is the Condorcet loser and is eliminated

>C's votes transfer to B at a value of 1.00.

>B (51) wins against A (49).

>If debate where allowed between the ESBS voting rounds the voters/ 
candidates >may well realise that everybody rates B highly and elect him/her.

>Donald: No No David! Debate or no debate, the voters of A and C are going
>to stone wall and hold their position and why not, their most preferred
>candidae is close to victory, all he needs is two or three points. No,
>instead of electing B, the A and C voters will expect B to withdraw. They
>will wait for that to happen and/or for the B voters to change their votes
>(regardless if B withdraws).   

As the original example shows for a candidate with such a low first 
preference to win he/she needs to be very highly rated by virtually the entire 
electorate. This may be an unrealistic situation and it may be that if B were that 
popular he/she would obtain more first preference support.

The only way to answer the question as to whether in the situation:

40 A>B
11 B>A
10 B>C
39 C>A

B is a high utility genuine compromise ( deserving of victory) or a low 
utility turkey is to use a ballot on which voters can express their utilities and 
an election method that takes the utilities into consideration in deciding the 
winner. In the example given above Condorcet in all elections for all sets of 
candidates treats B as a high utility compromise ( who should win ). IRV, by 
contrast, for all elections and all sets of candidates treats B as a low 
utility candidate who should not be elected.

Neither assumption is true in all circumstances.

David Gamble


    

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