[Election-Methods] Challenge

[Forest W Simmons]

Under strategic voting with good information, any decent deterministic 
method (including Approval) would elect the Condorcet Winner A .  
Uncertainty as to the faction sizes could get C elected, but not 
necessarily.

So some randomness is essential for the solution of this problem.   

The indeterminism has to be built into the method in order to make sure 
that it is there in all cases.

Jobst's D2MAC would work here because the compromises' 80 percent 
rating is above the threshold for sure election when the two faction 
sizes differ by ten percent or more, if I remember correctly.

If the compromise had only a 60 percent rating, for example, optimal 
strategy might give A a positive chance of winning.

It is paradoxical that randomness, usually associated with uncertainty, 
is the key to making C the certain winner.

Look up D2MAC in the archives for a more quantitative analysis.

I hope that this doesn't prematurely take the wind out of the challenge.

Forest

>From: Jobst Heitzig <heitzig-j at web.de>
>Subject: [Election-Methods] Challenge: Elect the compromise when
>	there're	only 2 factions
>To: election-methods at lists.electorama.com
>Message-ID: <445065910 at web.de>
>Content-Type: text/plain; charset=iso-8859-15
>
>A common situation: 2 factions & 1 good compromise.
>
>The goal: Make sure the compromise wins.
>
>The problem: One of the 2 factions has a majority.
>
>A concrete example: true ratings are
>   55 voters: A 100, C 80, B 0
>   45 voters: B 100, C 80, A 0
>
>THE CHALLENGE: FIND A METHOD THAT WILL ELECT THE COMPROMISE (C)!
>
>The fine-print: voters are selfish and will vote strategically...
>
>Good luck & have fun :-)
>