[EM] 2-step CR: A proposal

[Richard Moore]

Alex Small wrote:
> Suppose that in a CR election with 3 candidates the voters are trying to
> decide their strategies.  Suppose that polling data makes it quite clear
> that most people have already made up their minds about my least favorite
> and compromise candidates, but it's impossible to tell right now how my
> favorite will fare.  Suppose also that my least favorite is slightly ahead
> of my compromise.
> 
> People who share my set of relative preferences have a strong incentive to
> give our compromise candidate just enough votes so that he barely finishes
> ahead of our least favorite.  So, on a scale of 0 to 10 we might all rate
> our compromise as a 3.  We rate our favorite a 10, of course.  If enough
> people from other camps rate our favorite highly then he'll win.
> Otherwise, we'll at least block the election of our least favorite.
> 
> All of this assumes that we can coordinate, of course.
> 
> One other note:  Demorep once asked what scenario would generate
> probabilistic strategies.  Suppose that the above election had been held
> with Approval rather than CR.  In that case everybody who shares my
> preference order would give a vote to our favorite, and 30% of us would
> also give a vote to our compromise so he finishes just ahead of our least
> favorite.

So what you are saying is that the execution of the strategy would be
different between approval and CR, but the results would be the same.
Isn't this the same as saying that the two are equivalent when optimum
strategies are applied? ("Strategically equivalent" seems like slightly
sloppy terminology, that's why I reworded it to "equivalent when optimum
strategies are applied" -- does anyone have a better suggestion on the
wording?)

  -- Richard

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