range voting

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Range voting uses a ratings ballot; that is, each voter rates each candidate with a number within a specified range, such as 0 to 9[9] or 1 to 5. In the simplest system, all candidates must be rated. The scores for each candidate are then summed, and the candidate with the highest sum is the winner. (This is simpler for voters than cumulative voting, where they are not permitted to provide scores for more than some number of candidates.)

Some systems allow voters to explicitly abstain from rating certain candidates, as opposed to implicitly giving the lowest number of points to unrated candidates. In this case, a candidate’s score would be the average rating from voters who did rate this candidate. However, some method must then be used to exclude candidates who received too few votes, to provide a meaningful average.[10][11]

In some competitions subject to judges’ scores, a truncated mean is used to remove extreme scores. For example, range voting with truncated means is used in figure skating competitions to avoid the results of the third skater affecting the relative positions of two skaters who have already finished their performances (the independence of irrelevant alternatives), using truncation to mitigate biases of some judges who have ulterior motives to score some competitors too high or low.

Another method of counting ratings ballots is to find the median score of each candidate, and elect the candidate with the highest median score. This method is also referred to as Majority Judgment.[12][13] It could have the effect of reducing the incentive to exaggerate. A potential disadvantage is that multiway exact ties for winner may become common, although a method exists in Majority Judgment to break such ties.[12] In conventional range voting, these ties would be extremely rare. Another consequence of using medians is that adding an “all-zero ballot” can alter the election winner, which is arguably a disadvantage.

Another proposed variant, score runoff voting, uses score voting to choose the top two candidates, who are then pit against each other in an instant runoff based on the relative scores they received from each voter. The claimed advantages are a disincentive against strategic exaggeration, and a “majority winner” between the top two.[14]

Range voting in which only two different votes may be submitted (0 and 1, for example) is equivalent to approval voting. As with approval voting, range voters must weigh the adverse impact on their favorite candidate of ranking other candidates highly.

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