Definite Majority Choice: Difference between revisions

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Since the diagonal cells in the Condorcet pairwise matrix are usually left blank, those locations can be used to store each candidate's Approval point score.
Since the diagonal cells in the Condorcet pairwise matrix are usually left blank, those locations can be used to store each candidate's Approval point score.


We call a candidate [[Techniques_of_method_design#Defeats_and_defeat_strength|Definitively defeated]] when that candidate is defeated in a head-to-head contest against any other candidate with higher Approval score. This kind of defeat is also called an ''Approval-consistent defeat''.
We call a candidate [[Techniques_of_method_design#Defeats_and_defeat_strength|definitively defeated]] when that candidate is defeated in a head-to-head contest against any other candidate with higher Approval score. This kind of defeat is also called an ''Approval-consistent defeat''.


To determine the winner:
To determine the winner,
# Eliminate all definitively defeated candidates. Let us call the set of remaining candidates the Definite Majority set.
# Eliminate all definitively defeated candidates. We call the remaining candidates the '''definite majority set'''.
# The winner is the single candidate who pairwise defeats (wins head-to-head contests with) all other candidates in the Definite Majority set.
# The winner is the single candidate who pairwise defeats (wins head-to-head contests with) all other candidates in the definite majority set.


DMC always selects the [[Condorcet Criterion|Condorcet Winner]], if one exists, and otherwise selects a member of the [[Smith set]]. Step 1 has the effect of successively eliminating the least approved candidate in the Smith set and then recalculating the new Smith set, and repeating until a single winner exists. But Step 1 also allows higher-approved candidates outside the Smith set, such as the Approval Winner, to remain in the Definite Majority set.
DMC always selects the [[Condorcet Criterion|Condorcet Winner]], if one exists, and otherwise selects a member of the [[Smith set]]. Step 1 has the effect of successively eliminating the least approved candidate in the Smith set and then recalculating the new Smith set until a single winner exists. But the definite majority set may also contain higher-approved candidates outside the Smith set. For example, the Approval Winner will always be a member of the definite majority set.


DMC has some interesting properties:
DMC has some interesting properties:

* The DMC winner has the lowest total approval score of any candidate in the Definite Majority set.
* The DMC winner has the lowest total approval score of any candidate in the Definite Majority set.
* When defeat strength is measured by the approval of the defeating candidate, there is only one possible immune method, namely DMC.
* When defeat strength is measured by the approval of the defeating candidate, there is only one possible immune method, namely DMC.