Rated pairwise preference ballot: Difference between revisions
→Preference threshold
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== Implementations ==
These are mostly listed in order of simplicity for vote-counting.
=== Rated or ranked preference ===
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=== Preference threshold ===
<blockquote>It's possible to modify Score to be more like a traditional Condorcet method by allowing voters to write the scores they would give to every possible pair of candidates in a Score runoff, and then using a Condorcet method to process this, treating a score of, say, A5 B3 (where the max score is 5) as 0.4 votes for A>B. As this would be utterly infeasible with just a few candidates running however, one way to accomplish most of the same objective is to allow voters to mark on their ballots that they want their vote strategically optimized, meaning that if their cardinally expressed preferences are A5 B3 Z2, instead of having their vote considered as B3 Z2 in an B vs. Z runoff, it would be considered as B5 Z0 (if the max score is 5), which is functionally equivalent to the Plurality voting runoffs that are used for the traditional Condorcet winner definition
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The matchup between A and B is treated as weak because both candidates come before the threshold (i.e. the voter only gives 0.2 more votes to A than B, which is their scored preference of (5-4)/5=1/5th or 0.2 votes; keep in mind that when changing the scale from 0 to 5 to 0 to 1, the scores of 5 and 4 become 1 and 0.8 respectively, which is what you see in the pairwise table. It is also possible to put 0.2 and 0 instead, which captures only the margin and not the winning votes for the matchup), while all other matchups are treated as maximal (despite, for example, A>C only having a scored preference of (5-2)/5=3/5th or 0.6 votes, it is instead treated as a maximal preference of 1 vote).
=== Fractional optimization ===
<blockquote>
This strategic optimization can be done fractionally to allow a voter to customize how much optimization they want to be done with their scores in each runoff.</blockquote>
An example of fractional optimization on a scale of 0 to 5:
A:5 B:3 C:2 at 60% optimization
This would become an optimized preference of 76% or 0.76 votes for A>B, 68% for B>C, and 84% for A>C. This is derived by looking at how far apart the rated preference and maximal preference values are, applying the % of optimization to this difference, and adding the resulting value to the rated value. So for example, A>B is a rated preference of (5-3)/5=2/5ths or 40% strength. That is 60% shy of 100%, and 60% optimization multiplied by this 60% difference is 36%, which added back to the rated preference of 40% yields 76%.<blockquote>Note that when designing a ballot to allow voters to indicate strength of preference in pairwise matchups, it could be done by allowing the voters to rank or score the candidates themselves, and then indicate "between your 1st choice(s) and 2nd choice(s), what scores would you give to each in a pairwise matchup?" or "between the candidates you scored (max score) and the candidates you scored (max score - 1), what scores would you give in their pairwise matchups?", etc. Here is an example of one such setup: <ref>{{Cite web|url=https://www.reddit.com/r/EndFPTP/comments/fcz3xd/poll_for_2020_dem_primary_using_scored_pairwise/|title=r/EndFPTP - Poll for 2020 Dem primary using Scored Pairwise Matchups|website=reddit|language=en-US|access-date=2020-04-28}}</ref> and some discussion: <ref>{{Cite web|url=https://www.reddit.com/r/EndFPTP/comments/fimqpv/adjusting_pairwise_matchup_margins_to_favor/fkkldcl|title=r/EndFPTP - Comment by u/Chackoony on ”Adjusting pairwise matchup margins to favor higher-utility candidates”|website=reddit|language=en-US|access-date=2020-04-28}}</ref></blockquote>
== Notes ==
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