CR == Approval? Re: [EM] Re: Election-methods digest, Vol 1 #517 - 3 msgs

[Ernest Prabhakar]

Hi all,

On Feb 25, 2004, at 9:36 PM, Ken Johnson wrote:
>> CR is strategically equiovalent to Approval: In CR, you maximize your 
>> expectation by giving maximum points to those candidates for whom 
>> you'd vote in Approval, and giving minimum points to the rest.

This statement has always puzzled me.   I think the more precise 
statement is that the *optimal* strategy in CR is equivalent to the 
optimal strategy in Approval.  Technically, I believe an optimal 
strategy is one where there is no better defense than the same 
strategy.  Put another way, the most robust strategy for maximizing 
utility of outcomes is equivalent between CR and Approval.

However, it seems like there can well be extreme cases, due to either 
detailed information or sub-optimal strategic behavior by opponents, 
where a different strategy would actually be more -effective- (optimal 
doesn't mean perfect).   Thus, in those cases, the most effective 
strategy for CR would not be precisely identical to Approval, simply 
because the scenarios are slightly different.

Anyway, I think the statement "the optimal strategy for CR is the same 
as that for Approval" is both more technically precise, and less 
confusing, than the oft-repeated "CR is strategically equivalent to 
Approval" meme that gets kicked around here periodically, so I would 
like to recommend its adoption.

-- Ernie P.

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