[EM] CDTT,IRV

[Chris Benham]

Kevin,
I  had written:

> CDTT,IRV  is less vulnerable to Burial  than Defeat-Dropper(Winning 
> Votes)  or any other plain rankings method that meets
> Mutual Majority, Smith(Gross) and Clone Independence.

You helpfully gave this reply to a reply  from James G-A:

>40 A>B>C (sincere)
>25 B>A>C
>35 C>B>A
>
>IRV/FPP/DSC order is A>C>B; CDTT is {b}.
>
>40 A>C>B (insincere)
>25 B>A>C
>35 C>B>A
>
>IRV/FPP/DSC order is A>C>B; CDTT is {a,b,c}.
>
>Yes, CDTT methods have the same burial problem (and solution) as
>WV methods. That's one reason I suggest CDTT,RandomBallot.
>
Thanks for this clarification, which I'd wrongly hinted wasn't true. But 
take this really outrageous scenario (one of James G-A's):

46: A>B>C
44: B>C>A   (sincere is B>>>>A>C)
05: C>A>B
05: C>B>A

A is the sincere CW, and the (voted) CDTT is {A,B,C}.  Pairwise 
Defeat-Dropper(Winning Votes)  elects the Buriers' candidate B, while 
CDTT,IRV easily elects A.
With your suggestion CDTT,Random Ballot the Buriers increase the chance 
of their favourite winning from zero to 44%. This is a huge bargain for 
them if  their sincere ratings
gap between their second and last preference is much smaller than the 
one between their first and second preference. (In any case, here the 
chance of their sincere last preference
being elected only rises from zero to 10%).
So on balance I don't think CDTT,RB really resists Burying better than 
CDTT,IRV.

Chris Benham