http://wiki.electorama.com/wiki/Majority_Choice_Approval#Criteria_compliance
The Later-no-help criterion </wiki/Later-no-help_criterion> and the
Favorite Betrayal criterion </wiki/Favorite_Betrayal_criterion> are
satisfied by MCA-P
They are also met by "MCA-A", "MCA-M" and "MCA-S".
I consider it desirable that methods should have Later-no-Harm and
Later-no-Help in at
least approximate probabilistic balance. These methods all (badly) fail
Later-no-Harm, so meeting
LNHelp contributes to the strong truncation incentive.
They're also satisfied by MCA-AR if MCA-P is used to pick the two
finalists
That method does not meet the Favourite Betrayal criterion.
25: A
24: A>C
02: B>A
22: B
25: C>B
02: C=B (sincere is C>B)
No candidates' TR (or "P") score reaches the majority threshold of 51
and all their Approval
scores exceed it, so a resolution method is needed.
Of the candidates that reached a majority score, I gather the method
selects the two with the
highest TR scores for a runoff.
TR scores: A49, B26, C27.
The method selects A and C for the runoff, which A wins 51-27.
If the 2 C=B voters vote sincerely C>B the result is the same.
But if they change to B>C the TR scores change to A49, B26, C25 and
the method
then selects A and B for the runoff which B wins 51-49, a result those
two voters prefer.
25: A
24: A>C
02: B>A
22: B
25: C>B
02: B>C (was C=B, sincere is C>B)
Chris Benham
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