Ranked Robin: Difference between revisions

Ranked Robin is a [[Condorcet method|Condorcet voting method]] focused on the presentation of the results such that everyday voters can understand them without extensive education. Ranked Robin uses a [https://electowiki.org/wiki/Ballot#Ranked_ballot ranked ballot]. Voters are free to rank multiple candidates equally on their ballots. The candidate who wins the most head-to-head matchups against other candidates is elected, much like a [[w:round-robin tournament|round-robin tournament]]. AIn strict[[Election-methods seriesmailing oflist#Notation|the tienotation typically used on the EM-breakinglist]], mechanicsRanked areRobin is roughly "[[Copeland]]//[[Borda]]" with the addition of definedtiebreakers.

Ranked Robin was invented by [[User:Sass|Sass]] on 30 September 2021 and named by [[Sara Wolk]] on 7 November 2021. As an enthusiast of [[Cardinal voting systems|cardinal voting methods]] and a strong advocate for voter empowerment, Sass saw a timely need for a sufficiently-accurate [[Ranked voting|ranked voting method]] that was on par with the simplicity of voting methods like [[STAR Voting]] and even [[Approval Voting]], particularly in the [[United States]]. Ranked Robin is nearly identical to the earliest known Condorcet method, invented by [[Ramon Llull]] in his 1299 treatise ''Ars Electionis''<ref name="Hagele">{{cite journal |author1=G. Hägele |author2=F. Pukelsheim |lastauthoramp=yes | title=Llull's writings on electoral systems | journal=Studia Lulliana | year=2001 | volume=41 | pages=3–38 | url=http://www.math.uni-augsburg.de/stochastik/pukelsheim/2001a.html }}</ref>, which was similarly replicated by [[w:Marquis de Condorcet|Marquis de Condorcet]] centuries later, and then again by [[w:Arthur Herbert Copeland|Arthur Herbert Copeland]]. A mathematically identical method to Ranked Robin including the first tie-breaking mechanic was described by Partha Dasgupta and Eric Maskin in 2004<ref>{{Cite journal|last=Maskin|first=Eric|last2=Dasgupta|first2=Partha|date=2004|title=The Fairest Vote of All|url=https://scholar.harvard.edu/maskin/publications/fairest-vote-all|journal=Scientific American|volume=|issue=290|pages=64-69|via=Harvard University}}</ref>. The primary innovation of Ranked Robin is the reduction and formatting of results in such a way that they are palatable to a general audience, as a full [[Pairwise comparison matrix|preference matrix]] can be overwhelming for most voters. This innovation can likely be adapted to simplify the results of other voting methods that use [[pairwise counting]], particularly those that first restrict the set of winners such as [[Smith-efficient|Smith-efficient voting methods]].

{{Definition|Elect the candidate who pairwise beats the greatest number of other candidates.}}

==== Tie-breakingExample methodselection ====

|'''5256'''

|'''188204'''

|'''4751'''

|'''188204'''

|'''38'''

|''3539''

|''35'39'''

|''2832''

|'''138150'''

|''169181''

|''156168''

|''178190''

|''224232''

|'''10251069''' - ''10251069'' = <u>0</u>

'''2^nd Degree:''' Ava and Bianca tie for the greatest total difference in votes for and against all other candidates (both <math>188204-149=3955</math>).

'''3^rd Degree:''' Ava and Bianca tie for the least ''losing'' (and '''winning''') votes between them, ''149'' (and '''188204''').

When legally defined as ''always'' reducing to a finalist set first and then electing the finalist with the greatest total difference (Total Advantage) among finalists (as described in the '''1^st Degree''' tiebreaker), Ranked Robin always elects a majority preferred winner, arguably including in cases of '''2^nd Degree''' ties. This legal definition does not change the outcomes of Ranked Robin. Many municipalities in the [[United States]] are subject to a majority clausesclause in their respective state's election codescode, often requiring those jurisdictions to run two or more elections for a certain races. Ranked Robin can satisfy many of thosethese majority clauses in a single election, allowing municipalities to eliminate an election if so desired, helping to offset the costs of implementing Ranked Robin, typically entirely within one election cycle.

If there are multiple finalists, at least 1 finalist will have a positive difference (Total Advantage) and at least 1 finalist will have a negative differenceTotal Advantage because the sum of differencesadvantages will always equal 0. Because the finalist with the greatest differenceTotal Advantage is elected, that winner is guaranteed to have a positive differenceTotal Advantage, demonstrating that among finalists, they are a majority preferred winner.

If there is a '''2^nd Degree''' tie, all of the finalists could potentially (but rarely) have a negative differenceTotal Advantage when compared to all candidates, but it could be argued that because the ''finalist'' with the greatest differenceTotal Advantage is elected, the winner was voted for by a majority of voters who had a preference ''among finalists''. This argument is further strengthened in the case that exactly 2 finalists experience a '''2^nd Degree''' tie, which covers almost all cases of '''2^nd Degree''' ties. If this argument is found not to satisfy a particular majority clause, it may be desirable to leave the '''2^nd Degree''' tiebreaker out of the legislation and legally declare a tie in the equivalent case of a '''2^nd Degree''' tie, which is about as rare as a tie under [[First Past the Post electoral system|Choose-one Voting]].