Range voting

The evaluation choice (English Range voting ) is a voting system to be evaluated at the individual alternatives ( candidates) with points from a predetermined interval, for example, 0 to 99, 1 to 10, -5 to 5, or school grades. The points awarded (notes) are then averaged. The alternative with the best average score wins.

A vote choice is a very general and expressive voting procedures, as a voter each candidate assessed independently from the other applicants. At the same time, the rating option is a very easy to understand, intuitive and paradox -free system. In particular, the assessment of a candidate can not affect the relative placement of the other.

The reviews by a jury in many sporting disciplines by means of an assessment choice.

Description of the selection method

The determination of the election winner by vote choice is done in three steps: First, the evaluation of the candidates is conducted by the voters; it is followed for each candidate to determine the social evaluation, that is, the ratings of all voters are combined into one rating. Finally, the candidates will be placed in an order according to their ratings.

Voting

Each voter evaluates all candidates independently and selects for the evaluation of a scale of possible values ​​, such as the natural numbers from 0 to 9 This numbers can be assigned more than once, and of course does not have to use every number. It is also possible to give each candidate no note.

Candidate results

There are several variants of the valuation options to determine the outcome for each candidate:

• Average: Each candidate is assigned the average of the votes cast at him reviews.
• Total: Each candidate is assigned the sum of the votes cast at him reviews.

Note: Do all voters evaluate all candidates, both variants give the same result. The two versions differ only then, if not every voter has rated each candidate:

• In the mean variant undecided voters are ignored, that is, is not to assess a candidate, how to give him the average value.
• In the sum variant not present reviews are not added, that is, is not to assess a candidate, how to give it a 0.

Combinations are also possible: So beats about the U.S. " Center for Range Voting " the average variant before, but with all the candidates whose sum is less than half the highest achieved by a candidate sum excluded. This will prevent that little-known but fanatically supported by their own followers, thus presumably extremist candidate can win the election. This is when using the average variation in particular an absolute necessity if voters, as with many American elections prescribed by law, have the opportunity to enter a handwritten not appearing on the ballot candidates. Without such (or similar) usually someone could just enter it yourself and give yourself the highest score - probably because no one else has this person on the ballot, he would also get the highest possible average and thus win the election.

Winner

The candidate with the highest score is the winner.

Looking at the votes for a candidate ratings as a measure of satisfaction, has a voter with a candidate, the valuation option selects that candidate as the winner, which represents the highest social satisfaction.

Example

Consider an election with four candidates R, C, P and I and the following assessments by the 10 voters:

The evaluation choice candidate so R would win, because he achieved the best average of 7.6.

Remarks:

• Under instant runoff voting of the most unpopular in the average candidate I would win, since the deletion of the rear preferences are ignored ( Later - no-harm criterion ), whereby only the most popular in the average candidate R and then the second - most popular candidate C be deleted and the votes each migrate to I.
• If one uses the relative majority vote, so would P gain, since he would be the Erstpräferenz of 4 voters, while none of the other candidates by more than 3 candidates is the Erstpräferenz candidate. For the other 6 voters candidate P enjoys but very low esteem and would both Condorcet methods and the valuation option therefore lose.
• With a Condorcet method, candidate C would win because it is preferred to each other candidate by 6 voters. However, since the four voters who prefer R over C, R over C clearly prefer while preferring 6, C versus R, evaluate both candidates almost identical wins in the rating choice candidate R.

Properties

This selection process meets the most well-known voting system criteria, in particular dictatorship, completeness, independence of irrelevant alternatives and the weak Pareto principle.

The valuation option therefore seemingly violate the Arrow 's theorem, which excludes the existence of a rank -forming election procedure which meets these criteria. This effect arises from the fact that the Arrow 's theorem applies only to rank -forming electoral procedures (ie procedures in which candidates are placed by voters in an order), but not for absolute ratings (ie, processes in which voters score each candidate independently of the other ).

Furthermore, the valuation option fulfills the independence of clone alternatives, the consistency criterion, the participation criterion Transitivitätskriterium, the Favorite Betrayal criterion, the resolvability criterion and the reversal symmetry criterion.

The Condorcet criterion, the Condorcet loser criterion and the majority criterion is not met. Since the valuation option, however, allows to weight majorities and express how much more you an option of another preferred over during these criteria - as well as the rank -forming process, for which they were designed - not take into account this information, the validity of these criteria controversial for assessing choice.

The later- no-harm criterion is not satisfied: The output of a (lower) rating for a non- favored candidates can cause this candidate is chosen instead of the favored candidates. Suppose the voters for candidate B give tactical reasons the candidate A 0 points, while the voters also give the candidate B for candidate A points because B still considered the better option compared to C appears. Then it may be that B wins, although the A- voters had they voted exclusively for A, its candidate A could get through.

Alternatives

The biggest weakness of the valuation option with average is that few outsiders can influence the result greatly by assigning extreme values. The larger the scale, the stronger the effect. A possible consequence of this is a rating system with the smallest scale: Election by consent ( approval voting ). Only the points values ​​0 and 1 are possible. Critics argue, however, that by the advantage of the valuation option, namely the possibility of individuals to express their preferences differentiated, is lost.

In the case of a differentiated scale of influence of a small group of strategic voters can be captured by introducing a quorum. One possible form of such a quorum is a restrictive clause in analogy to parliamentary elections by proportional representation. Here, only those candidates would be considered, which have been assessed by a specified minimum number of voters or the electorate, for example 10 %. Another possibility is, each candidate an equal, fixed number of bad reviews as a " handicap " to be added to and form of the overall result ( Ratings 'handicap' ) the average.

Other ways to mitigate the influence of extreme evaluations are, instead of the average to use the median or to work with string results.