[EM] TTPD,TR (an FBC complying ABE solution?)

[Chris Benham]

Jameson,

49: C     (sincere)
27: A>B (sincere)
24: B     (sincere is B>A, but are trying to steal election from A).

 


________________________________




2011/11/20 C.Benham <cbenhamau at yahoo.com.au>


>Mike Ossipoff has been understandably concerned about what he calls the "Approval
>Bad Example" (ABE), as exemplified by
>
>49: C     (sincere)
>27: A>B (sincere)
>24: B     (sincere is B>A, but are trying to steal election from A).
> 

>He considers that a voting method must meet the Favorite Betrayal Criterion (FBC) and
>also he objects to the B voters in the above scenario being rewarded for their "defection"
>from the sincere {A,B} coalition (as they are with any method that meets both the Plurality
>and Minimal Defense criteria).
>
>I suggest this method to fill the bill. It uses Kevin Venzke's special "Tied-at-the-Top"
>pairwise rule.
>
>http://wiki.electorama.com/wiki/index.php?title=Tied_at_the_top
>
>*Voters submit 3-slot ratings ballots, default rating is Bottom signifying least preferred,
>Top rating signifies most preferred, the other ratings slot is Middle.
>
>According to the "Tied-at-the-Top" pairwise rule (TTP), candidate X beats candidate Y
>if the number of ballots on which X is given a higher rating than Y  *plus the number of
>ballots on which X and Y are both rated Top* is greater than the number of ballots on
>which Y is given a higher rating than X.
>
>(And of course vice versa, so it is possible for any pair of candidates X and Y that some
>ballots show Top rating for both to TTP beat each other).
>
>If any candidate X  TTP beats any candidate Y, is not in turn TTP beaten by Y and is
>not TTP beaten by any candidate Z that doesn't also TTP beat Y, then Y is disqualified.
>
>Elect the undisqualified candidate  that is rated Top on the highest number of ballots.*
>
>I think and hope this meets the FBC. If  it can be shown not to then I will withdraw my
>support for it.  It meets the Mono-add-Plump and the Plurality criteria.
>
>In the above example election no candidate is disqualified and C wins. If the B supporters
>vote sincerely then C will be disqualified and A will win.
>
>My suggested name for this method  "Tied at Top Pairwise Disqualification, Top Ratings"
>(TTPD,TR) is currently tentative and unenthusiastic, so if  it is agreed that it meets the FBC
>then I'm open to other suggestions.
>
>Chris Benham
>
>
>
>
>
>----
>Election-Methods mailing list - see http://electorama.com/em for list info
>




"You mean that sincere is B>A."

Yes, sorry for that blunder  (which I've fixed everywhere in this message). Thanks for pointing
it out.

"Also, it's not really important, but I've repeatedly pointed out that the term "chicken dilemma" 
is a more descriptive name for this situation, and also (as far as I know) one which has precedence."

I think the term "chicken dilemma" has quite a different connotation. Maybe I would just talk about
"defection incentive", but since Mike seems to be the one who is most concerned about it I'm happy 
for him to call it what he likes.

Chris Benham
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