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This page is a translated version of the page Wikimedia Foundation elections/Single Transferable Vote and the translation is 77% complete.
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A comparison of single-transferable vote (STV) and Meek STV voting methods with examples.

SecurePollでは、単記移譲式投票(Single Transferable Vote、STV)という選挙方式に対応しています。STVでは、有権者は当選してほしい候補者に対して優先順位をつけて投票します。SecurePollでは、Meek(ミーク)が実装した、ドループ式と呼ばれる計算方法を用います。


Wikimedia elections using STV


  • 立候補者: ワニ、クマ、ネコ、イヌ
  • 議席数:2名
  • 投票者:7名
投票者 ワニ クマ ネコ イヌ
投票者 1 - 第3選択 第2選択 第1選択
投票者 2 第4選択 第2選択 第3選択 第1選択
投票者 3 第1選択 第3選択 第4選択 第2選択
投票者 4 第1選択 第2選択 第3選択 第4選択
投票者 5 第3希望 第1選択 第4選択 第2選択
投票者 6 第1選択 第2選択 - -
投票者 7 第1選択 第4選択 第2選択 第3選択

ドループ最低得票数 = floor(有効投票総数/(議席数+1)) + 1 = floor(7/(2+1)) + 1 = 3


  • ワニ: 4票 - 当選
  • クマ: 1票
  • ネコ: 0票
  • イヌ: 2票



  • ワニ: 当選
  • クマ: 1 + 0.5 =1.5票
  • ネコ: 0 + 0.25 = 0.25票 - 除外
  • イヌ: 2 + 0.25 = 2.25票

Alligator has 1 surplus vote which will be redistributed according to the voters' second preferences.

Looking at all of Alligator's votes – 2 voters picked Bear second, 1 voter picked Cat second and 1 voter picked Dog second.

Alligator's surplus vote is split proportionately. Bear gets 0.5, Cat gets 0.25 and Dog also gets 0.25 additional vote.



  • ワニ: 当選
  • クマ: 1 + 0.5 + 0 =1.5票 - 除外
  • ネコ: 除外
  • イヌ: 2 + 0.25 + 0.25 = 2.5票

Cat got the lowest votes and was thus eliminated. Since Voter 7 has Dog as their 3rd choice after Alligator (already elected) and Cat (already eliminated), all of Cat's vote transfers to Dog.



  • ワニ: 当選
  • クマ: 除外
  • ネコ: 除外
  • イヌ: 2 + 0.25 + 0.25 +1.5 = 3.75票 - 当選

Bear received the lowest votes and was thus eliminated. Since voters 4 and 5 have Dog after Bear in their vote profile, a fraction of their votes get transferred to Dog, but since Voter 6 has not specified any candidates other than Alligator and Bear (already elected or eliminated), a quarter of their vote gets exhausted.

Dog reaches 3.75 votes which is above the threshold, thus declared elected.


  • 当選した候補者: ワニとイヌ
  • 除外: クマとネコ


  • いずれかの集計回で誰もドループ最低得票数を満たさなかった場合、最低得票数の候補を落選とし、その得票は投票者の選択順の順位にしたがって、他の候補者比例配分します。
  • もし残りの議席が1席となり、2名以上の候補者の得票数が同数であった場合は、システムは介入を認め、選挙管理者もしくは選挙管理員会に当落を決めます。
  • ご留意いただく点として、上記の例は簡略してあります。実際の算出では、ドループ最低得票数は集計回ごとに再計算され、こちらに示した規約に従います。
  • If two or more candidates tie for elimination in one of the intermediate rounds, we follow the "Short-cut exclusion rule" as outlined in this paper. This rule allows us to eliminate candidates when it is mathematically guaranteed that they can never win. This will happen when the candidate's votes don't exceed the votes by the next-best candidate even when they are assigned all the outstanding surplus votes. This seems a fairer method to decide eliminations as compared to randomly eliminating a candidate in the event of a tie. An example with a bigger election. Note that OpaVote/OpenSTV uses pseudo-random eliminations when it comes to ties. Hence their results may differ from ours in the event of a tie.
  • If a voter is already logged in to votewiki, they might see an error when they attempt to vote by going to the voting server from their home wiki. This can be fixed by going back to the home wiki and trying again. This is a known bug we are working on fixing.
  • Note: During the tally process numbers with high precision may not be accurately presented on the tally page. We are using PHP in the backend which supports extremely high precision. This is not easy to represent in the interface. However, this may impact eliminations/elections without the process being obvious to the end user. For example, if Candidate A has 86.00000000003 votes in a round and Candidate B has 86.0000000004 in a round, they both may be presented as having "86" votes but Candidate A will be eliminated as they have lesser votes than candidate B when the complete number is compared.