[EM] To Bill Lewis Clark, re: Approval, CR, & IRV

[Forest Simmons]

On Sun, 18 Jan 2004, MIKE OSSIPOFF wrote:

> Say we conducted an Approval vote, collected the ballots, and then said "Now
> we'll do another Approval balloting, whose results will be added to those of
> the previous balloting". How do you vote in the 2nd balloting? The same as
> in the 1st balloting.
>
> At electionmethods.org, in Approval Strategy I, I discuss considerations for
> voting in Approval. It has to do with how you rate the candidates, and
> certain probabilities that you estimate. In the 2nd balloting has any of
> that changed? Your ratings of the candidates haven't changed. Have the
> probabilities changed? Not unless your own vote could change the
> probabilties. And in a public election your vote isn't going to
> significantly change the probabilities.
>
> Therefore, in the 2nd balloting you vote exactly as you did in the 1st
> balloting. Likewise if there are additional ballotings.
>
> As I said, the votes in these ballotings are added together. Since you're
> voting for the same candidates each time, some candidates are getting the
> maximum possible number of votes from you and some are getting the minimum
> possible (zero).
>
> The election procedure that I've just described is the same as if CR were
> conducted one point at a time. "To which candiates would you give a point?";
> "To what candidates would you give a point in addition to anythng that you
> might have already given them?"...etc, N times.
>
> That's the same as saying "Give candidates point ratings from 0 to N".
>
> I've told you why it's to your advantage to give maximum points to all the
> candidates for whom you'd vote in Approval, and minimum points to the rest.

This is the best explanation of the strategical equivalence of CR and
Approval that I have ever read.

Forest