[EM] MCA in use

Adam Tarr atarr at purdue.edu
Sun Aug 11 11:00:04 PDT 2002

Joe Weinstein wrote:

>Our process could readily have been formalized as an MCA election among 
>candidates A-E.  Under usual Approval, B would have won; but in effect we 
>followed MCA, making A the clear winner.

I wouldn't be so sure that B would win in approval.  If everyone took the 
name "Approval Voting" at face value, and voted for all the candidates they 
considered acceptable, then yes, B would win.  But that's usually a poor 
strategy in Approval.  I've never seen anyone on this list seriously 
advocate it, although I have seen it used in letters to the editor and the 
like, where space considerations force things to be simplified.

The most popular strategy given out around here is "vote for the candidate 
you would vote for in a lone mark plurality election, and also vote for any 
candidates you like more."  A slightly better strategy is, "vote for all 
the candidates you like more than the front-runner, and vote for the front 
runner if you like him/her more than the second most popular 
candidate."  Most of the time these two are the same; they only differ when 
there are candidates you like more than the front-runner but less than the 
second place candidate.  Since from the sound of it, almost everyone liked 
A and B the best, this was not the case here.

So if the A supporters are even mildly strategic, they will vote for only A 
in an approval election, and A will win.  This assumes that people are 
aware that A and B are the front-runners, but for the sound of it this was 
the case here as well.


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