STLR voting: Difference between revisions
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'''STLR voting''' (pronounced 'Stellar Voting') is an [[Voting method|electoral system]] [[:Category:Single-winner voting methods|for single-seat elections]], though it can be extended to a [[Multi-member system]] with a sequential elimination method. The name stands for "score then levelled runoff", and can be thought of as a [[Utilitarianism | utilitarian]] version of [[STAR voting]]. It is a type of [[cardinal voting]] electoral system and while the name is a clear reference to [[STAR voting]] it is actually a
Voters cast ballots as in [[Score voting]], rating each candidate from 0
==Method==
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# The scores for each candidate are then summed
# The two candidates with the highest sums go to the runoff.
# On each ballot, the scores of these two are levelled by multiplying by the number such that the higher scored
#:* Explicitly, if the
# The levelled scores for each candidate are then summed and the winner is the one with the higher sum
==
The concept was invented by [[Equal Vote Coalition]] Director [[Keith Edmonds]] and was first proposed publicly in July 2020<ref>{{Cite web|url=https://forum.electionscience.org/t/a-new-star-variant/708/28|title=CES Forum Post|last=|first=|date=|website=|url-status=live|archive-url=|archive-date=|access-date=}}</ref>.
The originally proposed runoff normalization was that of [[Instant Runoff Normalized Ratings]] (IRNR) but was later modified to its current form. The version with IRNR normalization was previously and independantly invented by user lucasvb on Reddit<ref>{{Cite web|url=https://www.reddit.com/r/EndFPTP/comments/bl6zrq/score_then_automatic_cumulative_runoff/|title=score_then_automatic_cumulative_runoff|last=|first=|date=|website=|url-status=live|archive-url=|archive-date=|access-date=}}</ref>. The idea came from an attempt to solve the issue of arbitrary scale in [[Score voting]]. [[STAR voting]] solves this with the majoritarian runoff but as a result makes the system a majoritarian system.
=== Scale in Score Voting ===
When analyzing the ballots from the French studies<ref>“How voters use grade scales in evaluative voting” European Journal of Political Economy 55 (2018) 14–28, doi: 10.1016/j.ejpoleco.2017.09.006, Baujard, Gavrel, Igersheim, Laslier, and Lebon.</ref> <ref>Baujard, Antoinette & Igersheim, Herrade & Lebon, Isabelle & Gavrel, Frederic & Laslier, Jean-Francois. (2013). Who's Favored by Evaluative Voting? An Experiment Conducted During the 2012 French Presidential Election. Electoral Studies. 34. 10.1016/j.electstud.2013.11.003. </ref> and primary election for the Independent Party of Oregon <ref>{{Cite web|url=https://www.kdrv.com/content/news/Oregon-Independent-voters-favor-Biden-over-Trump-but-other-Republicans-over-Democrats-570644271.html|title=Oregon Independent voters favour Biden over Trump|last=|first=|date=|website=|url-status=live|archive-url=|archive-date=|access-date=}}</ref> a well known criticism of score voting arose. This is that some voters tend to be too honest and to not score any candidate at the <math>MAX</math> and <math>MIN</math> values. In a score election the amount of influence a voter has is the difference between the maximum and minimum score they give a candidate. The standard response is that voters are told how the system works and it is up to them to decide how to use the scores.
A related issue is that of deciding who gets a score of 0. Only the worst or just those unfavoured? What is typically advised is for voters to give their the maximum value to their favourite and zero to any candidate they do not support.
The final issue is then to decide how to scale the scores of semi-supported candidates. Should a candidate who is half as supported as the favourite get half the score? Is this linear scaling what all voters do or do some use a different way?
=== Problem of being Majoritarian ===
STAR is intended to be a compromise between [[score voting]] and [[instant runoff voting]].<ref>{{Cite news |url = http://equal.vote |title = Equal Vote Coalition |work = Equal Vote Coalition |access-date = 2017-04-05 }}</ref>. It solves the above issue of scale because as long as a preference is shown between the two candidates in the runoff then their influence is maximized. It is a majoritarian system as shown in the example
<poem>Red 51%: A[5] B[4] C[0] D[0]▼
Blue 49%: A[0] B[4] C[0] D[5]</poem>▼
It elects A when both Score and Approval voting elect B. B is a compromise and the [[Utilitarian winner]]. STAR argues that it is better because it recovers the way that people would have voted given the top two utilitarian winners. This solves the scale issue in score.
One can still solve the scale problem in score voting without resorting to majoritarianism with a different normalization. STAR
▲Red 51%: A[5] B[4] C[0] D[0]
▲Blue 49%: A[0] B[4] C[0] D[5]
In summary, the favoured candidate is levelled up to <math>MAX</math> so that all voters have the same maximum endorsement of the preferred candidate in the runoff. The less preferred candidate is given the same scaling so that the relative utility on the ballot is preserved. This means that the [[Utilitarian winner]] will be chosen in a runoff where each voter has equal influence.
It elects A when both Score and Approval voting elect B. STAR argues that it is better because it recovers the way that people would have voted given the top two utilitarian winners. STAR is basically [[https://electowiki.org/wiki/Baldwin%27s_method#Cardianal_Variant | Cardinal Baldwin]], but only doing the last round instead of all rounds. It is ONLY applying Baldwins method in the last step to normalize without losing monotonicity. Maybe the Baldwin normalization is not the best form of normalization since it reintroduces polarization and majoritarianism.▼
==Sequential elimination System==
▲One can still solve the scale problem in score voting without resorting to majoritarianism with a different normalization. STAR put the favoured candidate to the <math>MAX</math> but also puts the other candidate in the runnoff to 0. In orger to preserve utility the amount of utility that this candidate is worth to the voter needs to be preserved. Some assumption needs to be made and the assumption for STLR voting is that that relative utility should be constant.
▲
A similar sequential elimination method can be made by eliminating the worst candidate then applying the levelling to all remaining candidates. A [[Multi-member system]] can be made from this by stopping while there are still multiple candidates remaining.
This puts this new system in a class of systems with [[https://electowiki.org/wiki/Baldwin%27s_method#Cardianal_Variant | Cardinal Baldwin]] and [[IRNR]] distinguished by their normalization mechanisms.
==References==
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