Range voting
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Range voting (also called ratings summation, or average voting, or cardinal ratings, or 0-99 voting, or the score system or point system) is a theoretical voting system for single-seat elections in which voters score each candidate, the scores are added up, and the candidate with the highest score wins.
Voting System
Range voting uses a ratings ballot; that is, each voter rates each candidate with a number within a specified range, such as 0 to 99 or 1 to 5. Although in cumulative voting voters are not permitted to provide scores for more than some number of candidates, in range voting all candidates can be and should be rated. The scores for each candidate are summed, and the candidate with the highest sum is the winner. If voters are explicitly allowed to abstain from rating certain candidates, as opposed to implicitly giving the lowest number of points to unrated candidates, then a candidate's score would be the average rating from voters who did rate this candidate.Another method of counting ratings ballots is to find the median score of each candidate, and elect the candidate with the highest median score - see Median Ratings. A disadvantage is that with strategic voting, there may often be a multiway exact tie for winner - whereas, in conventional range voting, such ties are extremely rare. Tiebreaking schemes could be added to median-rating to overcome that objection.
Range voting in which only two different votes may be submitted (0 and 1, for example) is equivalent to approval voting.
Alternative Use
Although no significant electoral usage of range voting is known, the concept can be found in other areas. Sports such as gymnastics rate competitors on a numeric scale. On the Web, sites allow users to rate items such as movies (Internet Movie Database), comments (Kuro5hin), recipes, and many other things. Range voting is one of the voting methods endorsed by the Florida affiliate of the American Patriot Party. [link]Example
Imagine that the population of Tennessee, a state in the United States, is voting on the location of its capital. The population of Tennessee is concentrated around its four major cities, which are spread throughout the state. For this example, suppose that the entire electorate live in one of these four cities, and that they would like the capital to be established as close to their city as possible.
The candidates for the capital are:
- Memphis, the state's largest city, with 42% of the voters, but located far from the other cities
- Nashville, with 26% of the voters
- Knoxville, with 17% of the voters
- Chattanooga, with 15% of the voters
| 42% of voters (close to Memphis) | 26% of voters (close to Nashville) | 15% of voters (close to Chattanooga) | 17% of voters (close to Knoxville) |
|---|---|---|---|
|
|
|
|
- Memphis: 826,330
- Nashville: 510,784
- Chattanooga: 285,536
- Knoxville: 335,749
42% of voters (close to Memphis)
|
26% of voters (close to Nashville)
|
15% of voters (close to Chattanooga)
| 17% of voters (close to Knoxville)
|
Suppose that voters each decided to grant from 1 to 10 points to each city such that their most liked choice got 10 points, and least liked choice got 1 point, with the intermediate choices getting 5 points and 2 points.
| Voter from/City Choice | Memphis | Nashville | Chattanooga | Knoxville | Total |
|---|---|---|---|---|---|
| Memphis | 420 (42 * 10) | 26 (26 * 1) | 15 (15 * 1) | 17 (17 * 1) | 478 |
| Nashville | 210 (42 * 5) | 260 (26 * 10) | 30 (15 * 2) | 34 (17 * 2) | 534 |
| Chattanooga | 84 (42 * 2) | 130 (26 * 5) | 150 (15 * 10) | 85 (17 * 5) | 449 |
| Knoxville | 42 (42 * 1) | 52 (26 * 2) | 75 (15 * 5) | 170 (17 * 10) | 339 |
Nashville wins. But Memphis would have won if the voters from Memphis had reduced the points they gave Nashville from 5 down to 1 and all other votes had remained the same; voters from Chattanooga or Knoxville could restore Nashville to first place over Memphis if they raised the points they gave Nashville from 2 up to 10.
Properties
In contrast to rank ballot methods, range voting allows voters to express preferences of varying strengths.Range voting satisfies the monotonicity criterion, i.e. raising your vote's score for a candidate can never hurt his chances of winning, unlike in instant runoff voting (IRV). Also, in range voting, casting a sincere vote can never result in a worse election winner (from your point of view) than if you had simply abstained from voting. This stands in contrast to IRV and Condorcet methods, in which casting a sincere vote can even cause one's first preference to lose, or one's last preference to win. Range voting never gives voters an incentive to rate their favorite candidate lower than a candidate they like less. This is in contrast to IRV, Borda count, and Condorcet.
Range voting is independent of clones in the sense that if there is a set of candidates such that every voter gives the same rating to every candidate in this set, then the probability that the winner is in this set is independent of how many candidates are in the set. The original definition of clone independence only applied to ranked voting methods, however, and some disagree that it can be extended to range voting in this way.
Although range voting is not a Condorcet method according to many people's definition of that term, the [Center for Range Voting] has disputed that. The dispute is based on the fact that the definition of "Condorcet method" found in most political science books had implicitly assumed ranked voting methods. If one tries to extend the definition to allow range voting, then there are several inequivalent ways to do so, and under some of them range voting is, while in others it is not, a Condorcet method. That all is discussed [here].
In summary, range voting satisfies the monotonicity criterion, the participation criterion, the consistency criterion, independence of irrelevant alternatives, reversal symmetry, and the plurality criterion. It is immune to cloning, although that can be disputed. It does not satisfy either the Condorcet criterion (i.e. is not a Condorcet method) or the Condorcet loser criterion, although those non-satisfaction claims also have been disputed for essentially the same reason. It does not satisfy the majority criterion.
Strategy
In most cases (when the population is large or not much is known about how others will vote), the optimal strategy for range voting is to vote as under approval voting, so that all candidates are given (to very good accuracy) either the maximum score or the minimum score. However, it is possible to devise [examples] in which maxxing and minning out all votes is not optimal. Because of the near-equivalence of range and approval voting with 100% strategic voters, range voting can only exhibit substantial advantages over approval voting in situations in which at least some voters are actually expressing their personal feelings rather than doing everything they can to cause their most favored outcomes, i.e. in which there are some amount of nonstrategic "honest" (or at least partially honest) voters. Is that the case in the real world? The answer from many poll studies is "yes": range, approval, and plurality voting often all yield very different vote totals in the real world.Approval voting inventor Guy Ottewell [now endorses] range voting.
See also
- List of democracy and elections-related topics
- Consensus decision-making
- Decision making
- Democracy
- Hot or Not - a real world example
- Majoritarianism (Majority rule)
- Majority Choice Approval
- Minoritarianism
External links
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