Independence of the least/most preferred: Difference between revisions

From electowiki
Content added Content deleted
VisualWikitext
No edit summary
m (Linked mono-add-top to its own article.)
 
(2 intermediate revisions by 2 users not shown)
Line 1: Line 1:
Independence of the least/most preferred (ILMP) is satisfied when:
Independence of the least/most preferred (ILMP) is satisfied when:


ILP: By adding a vote where candidate X has the '''worst''' possible rating (or rank), then that vote doesn't '''increase''' the winning chance of X.
ILP: by adding a vote where candidate X has the '''worst''' possible rating (or rank), then that vote doesn't '''increase''' the winning chance of X.


and
and


IMP: By adding a vote where candidate X has the '''best''' possible rating (or rank), then that vote doesn't '''decrease''' the winning chance of X.
IMP: by adding a vote where candidate X has the '''best''' possible rating (or rank), then that vote doesn't '''decrease''' the winning chance of X.


This criterion must apply regardless of how the other candidates are rated.
This criterion must apply regardless of how the other candidates are rated.


Meeting these criterion favors the use of intermediate ratings (if present in the voting system), reducing tactics such as [[Tactical_voting#Definitions|min-maxing]].
Meeting these criterion favors the use of intermediate ratings (if present in the voting system), reducing strategies such as [[Tactical_voting#Definitions|min-maxing]]. Specifically, IMP avoids rating minimization, while ILP avoids rating maximization, and it's better.

Douglas Woodall's terms for these criteria are [[Mono-add-top|mono-add-top]] for IMP and [[Monotonicity#Woodall's_monotonicity_criteria|mono-remove-bottom]] for ILP.

[[Category:Voting system criteria]]

Latest revision as of 15:03, 22 June 2022

Independence of the least/most preferred (ILMP) is satisfied when: 

ILP: by adding a vote where candidate X has the worst possible rating (or rank), then that vote doesn't increase the winning chance of X.

and 

IMP: by adding a vote where candidate X has the best possible rating (or rank), then that vote doesn't decrease the winning chance of X.

This criterion must apply regardless of how the other candidates are rated.

Meeting these criterion favors the use of intermediate ratings (if present in the voting system), reducing strategies such as min-maxing. Specifically, IMP avoids rating minimization, while ILP avoids rating maximization, and it's better.

Douglas Woodall's terms for these criteria are mono-add-top for IMP and mono-remove-bottom for ILP.

Retrieved from "https://electowiki.org/wiki/Independence_of_the_least/most_preferred?oldid=16044"