[EM] Re: Efforts to improve on CR's strategy

Chris Benham chrisbenham at bigpond.com
Fri May 21 08:13:02 PDT 2004


>One way to look at this is that with one issue, you basically have two 
>types of candidates: liberal (positive CP) and conservative (negative 
>CP). Candidates can be "strong" or "weak" liberals (or conservatives) 
>based on the magnitude of their CP's. Similarly, voters are either 
>liberal (normalized W equal to +1) or conservative (normalized W equal 
>to -1). In the simplest no-strategy case, all liberal voters vote for 
>liberal canditates and conservative voters vote for conservative 
>candidates. If there are 5 liberal candidates, 5 conservative 
>candidates, 51 liberal voters, and 49 conservative voters, then under 
>Approval all 5 liberal candidates will get 51 votes and all 5 
>conservative voters will get 49 votes. Thus the majority candidates will 
>all be tied, and whatever method is used to break the tie will not 
>likely result in the most liberal candidate (the CR winner) being selected.
>
>Ken Johnson 
>
In this scenario, if  the  "Candidate Positions" are evenly spaced,  the 
sincere CR winner would be the LEAST  liberal
candidate. If  this candidate has any first-preference supporters, then 
this candidate will also be the sincere Condorcet
winner (because this candidate's supporters can combine with all the 
conservative voters to pairwise beat all the more
liberal candidates  and with all the other liberal voters to pairwise 
beat all the conservative candidates.)

If this candidate has no first-prefernce supporters (so, unlike the 
candidates, the voters are not evenly-spaced) then of
course it is possible that any of  the liberal candidates could be the 
the CW (and maybe also the outright majority favourite)
but given the presence of a bare minority of  conservative voters, it 
isn't possible that the MOST liberal candidate could be
the sincere CR winner (which I take to mean the candidate with the 
highest "Social Utility").

Chris Benham





More information about the Election-Methods mailing list