Difference between revisions of "Later-no-harm criterion"

From Electowiki
Jump to: navigation, search
 
Line 2: Line 2:
  
 
<p><em>Adding a preference to a ballot must not decrease the probability of election of any candidate ranked above the new preference.</em></p>
 
<p><em>Adding a preference to a ballot must not decrease the probability of election of any candidate ranked above the new preference.</em></p>
 +
 +
The reasoning behind this criterion is that the voter should feel free to vote his complete ranking of the candidates, without fear that he is "giving away" information about his lower choices that the method may use against him.
  
 
<h4 class=left>Complying Methods</h4>
 
<h4 class=left>Complying Methods</h4>
  
 
<p>Later-no-harm is satisfied by [[Plurality voting|First-Preference Plurality]], [[IRV|Instant Runoff Voting]], [[Minmax|Minmax(pairwise opposition)]], Douglas Woodall's [[Descending Solid Coalitions]] method, and [[Random Ballot]]. It is failed by virtually everything else.</p>
 
<p>Later-no-harm is satisfied by [[Plurality voting|First-Preference Plurality]], [[IRV|Instant Runoff Voting]], [[Minmax|Minmax(pairwise opposition)]], Douglas Woodall's [[Descending Solid Coalitions]] method, and [[Random Ballot]]. It is failed by virtually everything else.</p>

Revision as of 21:18, 22 March 2005

Statement of Criterion

Adding a preference to a ballot must not decrease the probability of election of any candidate ranked above the new preference.

The reasoning behind this criterion is that the voter should feel free to vote his complete ranking of the candidates, without fear that he is "giving away" information about his lower choices that the method may use against him.

Complying Methods

Later-no-harm is satisfied by First-Preference Plurality, Instant Runoff Voting, Minmax(pairwise opposition), Douglas Woodall's Descending Solid Coalitions method, and Random Ballot. It is failed by virtually everything else.