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In elections that use the single transferable vote (STV) method, ''quotas'' are used (a) for the determination of candidates considered elected; and (b) for the calculation of surplus votes to be redistributed.〔Hill, I.D. (1987). "(Algorithm 123 — Single Transferable Vote by Meek’s method )".〕 Two quotas in common use are the Hare quota and the Droop quota. ==General comparison== The earliest versions of STV used the Hare quota. The Hare quota is equal to the total valid poll (V) divided by the total number of seats (n), or V / n. The Droop quota is smaller than the Hare quota, and was first suggested 〔Henry Richmond Droop, ("On methods of electing representatives" ) in the ''Journal of the Statistical Society of London Vol. 44 No. 2'' (June 1881) pp.141-196 (197-202 ), reprinted in ''Voting matters Issue 24'' (October 2007) pp.7–46.〕 because it is the smallest quota that, like the Hare quota, ensures that the number of candidates who reach the quota will not be greater than the number of seats to be filled. Any quota smaller than the Droop quota carries a real, or at least theoretical, risk of more candidates being elected than there are seats to be filled. The Droop quota is the next integer larger than V / (n+1). The difference between the two quotas comes down to what the quota implies. Winners elected under a Hare system represent that proportion of the electorate; winners under a Droop system were elected by that proportion of the electorate. In an STV election in which there is only one seat to be filled (in other words an Instant Run-off Voting election) it is possible to use the Hare quota, which will simply be equal to 100% of votes cast. However, it is more efficient to use the Droop quota, which will be equal to an absolute majority of votes cast, meaning 50% plus one, and both quotas will achieve the same result. When voters have only one vote—the single non-transferable vote system—a candidate is sure to win if reaching the Droop quota. In an STV election in which there are multiple winners the situation is slightly different, particularly with respect to the final seat. *The Hare quota is generally kinder to small parties than the Droop quota because they have a better chance to win the final seat. Elected winners with the Hare quota more closely represent the proportionality of the electorate, and this can mean more proportional results for small parties. But this comes at the expense of emphasising the principle of majority rule. In an open list election held under the Hare quota it is possible for a group of candidates supported by a majority of voters to receive only a minority of seats if those voters do not disperse their vote relatively evenly across all their supported candidates, see Scenario 1 below. In contrast, such an outcome will not happen in an election held under the Droop quota unless voters in the majority do not rank all their preferred candidates or not enough preferred candidates seek office. *The Droop quota is generally kinder to large parties because ''they'' have a better chance to win the final seat. This comes at the expense of emphasising the principle of proportional representation. In an election held under the Droop quota it is possible for a group of candidates to over-represent a proportion of voters even though a majority of the remaining voters support a minor party, see Scenario 2 below. The Droop quota is today the most popular quota for STV elections - and almost universal for government STV elections - for two reasons . First, because it can more efficiently elect candidates in the each round of distribution of seats (whether STV or list PR) than is the case with the Hare quota. Second, because the possibility under the Hare quota that a group of candidates supported by a majority of voters to receive only a minority of seats is considered undemocratic . Examples of the different outcomes between the Hare and the Droop quotas follow: 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「Comparison of the Hare and Droop quotas」の詳細全文を読む スポンサード リンク
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