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The Wright system is a refinement of rules associated with proportional representation by means of the single transferable vote (PR-STV) electoral system. It is named after Jack Wright, former President of the Proportional Representation Society of Australia) The aim of the system is to provide an alternative to various methods of segmentation and distribution of preferences associated with the exclusion of a candidate from the count. The Wright System fulfills the two principles identified by Brian Meek: * ''Principle 1''. If a candidate is excluded from the count, all ballots are treated as if that candidate had never stood. * ''Principle 2''. If a candidate has achieved the quota, they retain a fixed proportion of the value of every vote received, and transfers the remainder to the next non-excluded continuing candidate, the value of the retained total equalling the quota. The system uses the optional Droop Quota (the integer value of the total number of votes divided by one more than the number of vacant positions plus one) and the Gregory method of weighted surplus transfer value of the vote in calculating a candidate's surplus transfer value which is then multiplied by the value of each vote received by the candidates whose votes are to be redistributed, as is the case in the Western Australian upper-house elections. Unlike the Western Australian upper-house electoral system, the Wright System uses a reiterative counting process that differs from the Meek's method as an alternative to the method of segmentation and distribution of excluded candidates' votes. On every exclusion of a candidate from the count the counting of the ballot is reset and all valid votes are redistributed to candidates remaining in the count initially at full value. In each iteration of the count, votes are first distributed according to the voter's first available preference, with each vote assigned a value of one and the total number of votes tabulated for each candidate and the quota calculated on the value of the total number of valid votes using the Droop quota method. Any candidate that has a total value equal or greater than the quota is provisionally declared elected and their surplus value distributed according to the voter's nominated subsequent preference. If the number of vacancies are filled on the first distribution the results of the election are declared with all provisionally declared candidates being declared the winner of the election. If the number of candidates provisionally declared elected is less than the number of vacancies and all candidates' surplus votes have been distributed then the candidate with the lowest value of votes is excluded from the count. The ballot is reset and the process of redistribution restarted with ballot papers being redistributed again according to the voters next available preference allocated to any continuing candidate. This process repeats itself until all vacancies are filled in a single count without the need for any further exclusions. The Wright System takes into account optional preferential voting in that any votes that do not express a valid preference for a continuing candidate are set aside without-value and the quota is recalculated on each iteration of the count following the distribution of the first available preference. Votes that exhaust as a result of a candidate's surplus transfer are set aside with the value associated with the transfer in which they exhausted. The main advantage of the Wright System is that it limits the distortion and bias in the vote that arises from the adopted methods of segmentation and distribution of preferences of excluded candidates. Each vote has proportionally equal weight and is treated in the same manner as every other vote. Under the current system used in the Australian Senate a voter whose first preference is for a minor candidate and their subsequent second preference for a major candidate that has been declared elected earlier in the count is denied the opportunity to have their second preference vote allocated to the candidate of their choice. With the reiterative counting system the voter's second preference forms part of the voter's alternative chosen candidate's surplus and is redistributed according to the voters nominated preference allocation. ==Definitions== Candidate means the name of a person or persons seeking election and listed on the ballot paper(s) to be counted Continuing Candidate means a candidate that has not been excluded from or declared not-elected in the process of the count Total Vote (Tv) is the total number of ballot papers that express a valid preference allocated to candidates remaining in the count Quota )Droop Quota(Q) means the number determined by dividing the Total Vote (Tv) by 1 more than the number of candidates required to be elected and by increasing the quotient (disregarding any remainder) (Q = integer(Tv/(1+No of Vacancies))+1) or Alternatively a Full Proportional Quota (Q) means the number determined by dividing the Total Vote (Tv) by the number of candidates required to be elected (disregarding any remainder) Value of the Vote (Vv) means the value allocated to each ballot paper as it progresses though the count. Candidate’s Total Value of votes (Ctvv) means the aggregated sum of the value of each ballot paper allocated to the candidate. Surplus Value (Sv) means the value calculated by subtracting the Quota (Q) from the Candidates Total Value’ of votes (Sv = Ctvv-Q) Surplus Transfer Value (Stv) means the value calculated by the Surplus value (Sv) divided by the Candidate’s Total Value of votes (Ctvv) and then multiplied by the Value of vote (Vv) allocated to each ballot paper ((Stv = Sv/Ctvv) *Vv) Ballot Paper means a record of a voter’s intention and allocation, in ascending order of preference, of support for a nominated candidate for election. It also refers to a vote which is a record in electronic format representing information and preference allocations of a ballot paper. Vote means a mathematical representation and record of a ballot paper Preference means the number in ascending order that represents the order of voter’s preference attributed to a candidate for election as recorded on a ballot paper or data file. Electronic preference data file means an electronic data file representing the allocation and record of preferences and all votes/ballot papers used in the calculation, distribution and determination of the results of the election. Remainders represent the fractional part arising from a mathematical division recorded in double precision and are to be retained with and form part of the value of the vote and/or the total value attributed to a candidate Exhausted Votes means the aggregated value attributed to any votes that do not express a valid preference for a candidate remaining within the count. The ballot paper and it’s attributed value are declared exhausted and a tally of all exhausted votes recorded. Bulk exclusion means the method of determining the number of candidates which can be simultaneously excluded from the count Running Sum means the progressive calculation the sum of all candidates total votes from lowest to highest in descending order Quota Breakpoint means highest running sum value that is less than half of the ''Quota'' Running Breakpoint means the candidate with a total vote value that is greater than the associated running sum of all candidates with a lower total vote. Applied Breakpoint means the candidate with a highest total vote that is less than the associated running sum of all candidates with a lower total vote and less than the difference between the ''Quota' and the value of the highest scoring candidate that is below ''Quota''. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Wright system」の詳細全文を読む スポンサード リンク
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