Later-no-harm criterion: Difference between revisions
The Condorcet criterion is incompatible with LNH, so it can't be equated 100% with majoritarianism.
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(The Condorcet criterion is incompatible with LNH, so it can't be equated 100% with majoritarianism.) |
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<p>'''Later-no-harm''' (usually LNH, but sometimes LNHa or LNHarm to avoid confusion with [[Later-no-help]]) is satisfied by [[IRV|Instant Runoff Voting]], [[Minmax|Minmax(pairwise opposition)]], and Douglas Woodall's [[Descending Solid Coalitions]] method. It is trivially satisfied by [[Plurality voting|First-Preference Plurality]] and [[Random Ballot]], since those methods do not usually regard lower preferences. Virtually every other method fails this criterion.</p>
<p>'''Later-no-harm''' is incompatible with the [[Condorcet Criterion|Condorcet criterion]].</p>▼
<h4 class=left>Commentary</h4>
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'''Later-no-harm''' guarantees that the method will not use a voter's lower preferences to elect a candidate who that voter likes less than the candidate that would have been elected if this voter had kept his lower preferences a secret.
As a result, voters may feel free to vote their complete ranking of the candidates, which in turn may give the election method more complete information to use to find a winner. There is a tradeoff however, in that this criterion simultaneously minimizes the amount of information that the voting method can use to find a winner.
This criteria is equivalent to the criteria that the system is non-
It is believed that some methods fail LNH at higher rates than others. For example, [[Condorcet methods]] are expected to fail less often than something like [[Score voting]].
▲This criteria is equivalent to the criteria that the system is non-compramizing in that it will never elect a compromise or [[Utilitarian winner]]. This insistence on majoritarianism is not universally desired so it cannot be claimed that this criteria is always one which would be desirable to pass. If one wants a system which can elect a compromise winner then it would be desirable to fail this criteria.
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▲'''Later-no-harm''' is incompatible with the [[Condorcet Criterion|Condorcet criterion]].
[[Category:Voting system criteria]]
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