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The Borda count is a single-winner election method in which voters rank options or candidates in order of preference. The Borda count determines the outcome of a debate or the winner of an election by giving each candidate, for each ballot, a number of points corresponding to the number of candidates ranked lower. Once all votes have been counted the option or candidate with the most points is the winner. Because it sometimes elects broadly acceptable options or candidates, rather than those preferred by a majority, the Borda count is often described as a consensus-based voting system rather than a majoritarian one. The Modified Borda Count is used for decision-making. For elections, especially when proportional representation is important, the Quota Borda System is used. The Borda count was developed independently several times, but is named for the 18th-century French mathematician and political scientist Jean-Charles de Borda, who devised the system in 1770. It is currently used to elect members of the Parliament of Nauru and two ethnic minority members of the National Assembly of Slovenia,〔("Slovenia's electoral law" )〕 in modified forms for apportionment of all seats in the Icelandic parliamentary elections, and for selecting presidential election candidates in Kiribati. It is also used throughout the world by various private organizations and competitions. ==Voting and counting== Under the Borda count the voter ranks the list of candidates in order of preference. So, for example, the voter gives a '1' to their first preference, a '2' to their second preference, and so on. In this respect, a Borda count election is the same as elections under other ranked voting systems, such as instant-runoff voting, the single transferable vote or Condorcet methods. The number of points given to candidates for each ranking is determined by the number of candidates standing in the election. Thus, under the simplest form of the Borda count, if there are five candidates in an election then a candidate will receive five points each time they are ranked first, four for being ranked second, and so on, with a candidate receiving 1 point for being ranked last (or left unranked). In other words, where there are ''n'' candidates a candidate will receive ''n'' points for a first preference, ''n'' − 1 points for a second preference, ''n'' − 2 for a third, and so on, as shown in the following example: Alternatively, votes can be counted by giving each candidate a number of points equal to the number of candidates ranked lower than them, so that a candidate receives ''n'' − 1 points for a first preference, ''n'' − 2 for a second, and so on, with zero points for being ranked last (or left unranked). In other words, a candidate ranked in ''i''th place receives ''n''−''i'' points. For example, in a five-candidate election, the number of points assigned for the preferences expressed by a voter on a single ballot paper might be: While the first of the above two formulae is used in the Slovenian parliamentary elections (as mentioned, for two out of 90 seats only), Nauru uses a sort of modified Borda count: the voter awards the first-ranked candidate with one point, while the second-ranked candidate receives half of a point, the third-ranked candidate receives one-third of a point, etc. (A similar system of weighting lower-preference votes was used in the 1925 Oklahoma primary electoral system.) Using the above example, in Nauru the point distribution among the five candidates would be this: When all votes have been counted, and the points added up, the candidate with most points wins. The Borda count is a preferential voting system; because, from each voter, candidates receive a certain number of points, the Borda count is also classified as a positional voting system. Other positional methods include First-past-the-post voting, bloc voting, approval voting and limited voting. 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「borda count」の詳細全文を読む スポンサード リンク
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