[EM] (no subject)

[Dgamble997 at aol.com]

Bart Ingles wrote:

>I think when mentioning criteria, it's a good idea to also state why
>those criteria might be important. For example, to me criteria such as
>FBC and Participation are important because they relate to a voting
>system's immunity to the Duverger effect.

>Approval meets both of these criteria, while the Condorcet methods
>appear to meet them whenever a CW is present. Borda and IRV fail these
>criteria under a wider variety of conditions, therefore both would tend
>to reinforce the two-party system, and to restrict the number of viable
>choices available to voters in non-partisan elections.

In my opinion the first criterion a single seat method must satisfy in order 
to be acceptable is :

If a candidate is the first choice of a majority of voters (50% +) that 
candidate must win.

IRV, Condorcet, Bucklin and Plurality pass this criterion, Approval and Borda 
fail it.

Take the example:

The voter preferences are:

510 A>B
145 B>A
145 B>C
200 C>B

In the Approval election these voters cast the following votes:

A 387
AB 123
BA 44
B  202
BC 44
CB 150
C 50

A is approved by 554 voters, B is approved by 563 Voters and C is approved by 
244 voters. Even though A is the first choice of a majority B wins.

As regards Duverger he said the following:

> To these socio-economic and historical factors a technical factor must be 
> added: the electoral system. I expressed its effects in 1946 in the 
> formulation of three sociological laws: (1) a majority vote on one ballot is conducive 
> to a two-party system; (2) proportional representation is conducive to a 
> multiparty system; (3) a majority vote on two ballots is conducive to a 
> multiparty system, inclined toward forming coalitions.

http://www.janda.org/c24/Readings/Duverger/Duverger.htm

Majority vote on two ballots (the electoral system of the French Third and 
Fifth Republics) is extremely similar to IRV and top two runoff.

How is participation (surely the winner of the September objective criterion 
of the month prize under any method) relevant to Duverger ?

David Gamble


    




    
    



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