FAIR-V: Difference between revisions
FAIR-Max diagram added
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[[File:FAIR-V Procedure.svg|
[[File:FAIR-Max Procedure.svg|350px|thumb|right]]
First-Approval Instant-Runoff
The objectives of this voting system is the balance between simplicity, resistance to strategies, and elect the utilitarian winner.
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The above elimination is repeated until only one candidate is left, who is the winner.
''Note: worst candidates for a voter are those (among the remaining) with the lowest rating in his ballot.''
''The original idea was [[FAIR-V#FAIR-Max|FAIR-Max]], which was then simplified to FAIR-V.''
===Normalization===
The actual FAIR-V algorithm uses
===Name derivation===
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First-Approval Instant-Runoff Voting:
* "First-Approval": the vote is initially treated as a multiple-choice. However, if all the worst candidates are eliminated in a vote, then the initial multiple-choice is reduced and can become a single-choice, during the count. It's like a single-choice (refer to [[FPTP|'''F'''PTP]]) masked at the beginning by multiple-choice (refer to [[Approval AV|'''A'''pproval voting]]).
* "
FAIR-
*FAIR-1V: it's equivalent to [[Approval AV|AV]], with ratings in [0,1].
*FAIR-V: is the default definition, with ratings in [0,3].
*FAIR-5V: uses ratings in [0,5].
*FAIR-9V: uses ratings in [0,9].
==FAIR-Max==
It's FAIR-V, with range [0,3], in which:
* the elimination ends when 2 candidates remain (finalists).
* in each vote, if 1 of the 2 finalists has obtained rating 0, then his opponent receives rating 3.
* the finalist with the highest sum of ratings is the winner.
''FAIR-Max resists maximization strategies (like FAIR-V), elect the utilitarian winner (much more than FAIR-V), but it's more complicated to explain (than FAIR-V).''
''FAIR-S: by removing step 2 from the list, the method resists a little less to maximization strategy, but becomes simpler and remains utilitarian.''
===mdM norm (min-do-Max norm)===
Given a range vote, with 2 candidates:
* if one of the two candidates has the minimum rating of the range, then his opponent receives the maximum rating of the range ''(no changes are made if both or none have a minimum rating)''.
===Mdm norm (Max-do-min norm)===
Given a range vote, with 2 candidates:
* if one of the two candidates has the maximum rating of the range, then his opponent receives the minimum rating of the range ''(no changes are made if both or none have a maximum rating)''.
===mM-do-Mm norm===
Apply both mdM and Mdm norms.
==Strategies resistance==
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* decreasing rating of the candidate X in one vote doesn't change the chance of victory for candidates rated below the new rating of X.
These properties mean that in FAIR-V a voter cannot favor a candidate more than the worst ones, by increasing his rating (avoid the strategy of maximization but not the one of minimization).
Example, given this honest vote:
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