Descending Solid Coalitions: Difference between revisions
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Every possible set of candidates is given a score equal to the number of voters who are ''solidly committed'' to the candidates in that set. A voter is solidly committed to a set of candidates if he ranks every candidate in this set strictly above every candidate not in the set.
When only one candidate is still eligible to win, that candidate is elected.
A variation of this method is [[Descending Acquiescing Coalitions]] (DAC).
== Properties ==
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DSC fails the [[Condorcet criterion]], the [[Smith set|Smith criterion]] and the [[Later-no-help criterion]].
DSC can be considered a [[Plurality voting|First-Preference Plurality]] variant that satisfies Clone Independence. It is (along with [[Descending Acquiescing Coalitions|DAC]])
===Example===
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The sets have the following strengths:
* 100 {M,N,C,K}
* 58 {N,C,K}
* 42 {M,N,C}
* 42 {M,N}
* 42 {M}
* 32 {C,K}
* 26 {N,C}
* 26 {N}
* 17 {K}
* 15 {C}
{N,C,K} is the strongest set that excludes a candidate. Memphis becomes ineligible.
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Notice that more than half of the votes held Memphis to be the worst alternative, yet the Memphis supporters' votes were still useful in securing their second choice, Nashville. If the Memphis voters had not listed any preferences after Memphis, the winner would have been Chattanooga.
Since DSC satisfies [[Later-no-harm criterion|Later-no-harm]], it's not possible for a voter to get a better result by withholding lower preferences, or to hurt the chances of a candidate already ranked by ranking additional candidates below that candidate. Since
[[Category:Single-winner voting
[[Category:Ranked voting methods]]
[[Category:Monotonic electoral systems]]
[[Category:Clone-independent electoral systems]]
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