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The Single Transferable Vote: Workings and Implications.

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Presentation on theme: "The Single Transferable Vote: Workings and Implications."— Presentation transcript:

1 The Single Transferable Vote: Workings and Implications

2 Election Services Group2 Today we will learn about how the STV system works. You will be successful if you can: Describe how voters make their choice Give 2 reasons why people think STV is a fair system.

3 Election Services Group3 STV in practice ©: Used in Northern Ireland for election to the NI Assembly and European Parliamentary elections. Used in Scottish local government elections for the first time in 2007.

4 Election Services Group4 Overview: Single Transferable Vote Proportionality What STV does How STV works A narrated example Summary of points about STV

5 Election Services Group5 Introduction: The principle of proportionality © A majority of voters deserves a majority of representation. Seats should fairly reflect votes cast. As many people as possible should have their one vote count towards representation.

6 Election Services Group6 What STV does © Allows voters to express a full and sincere ordering of choices by ranking candidates. Helps ensure fairer representation. Encourages a wider range of candidates to run Achieves proportional representation. Big groupings of voters win more seats, small groupings win fewer seats – everyone gets a fair share.

7 Election Services Group7 How STV works: The basics © A candidate wins a seat by receiving a share of the vote roughly equal to the number of votes divided by the number of seats. Voters rank candidates in order of preference (first, second, third and so on) for as many candidates as they wish. Ranking additional candidates will not affect the chances of a higher-ranked candidate.

8 Election Services Group8 AMS Ballot PaperSTV Ballot Paper

9 Election Services Group9 How STV works: Victory threshold To allow as many voters as possible to elect a candidate, the victory threshold is set as the lowest share of the vote that only the winning number of candidates can receive. The victory threshold equals: [Total votes cast / (Seats + 1)] + 1 vote* *disregarding fractions For example, when voters with 2,000 votes elect one seat, winning requires (2,000/2) + 1: 1,001 votes, 50.1% Likewise, when voters with 2,000 votes elect 18 seats, winning a seat requires (2,000/19) + 1: 106 votes, or 5.3%

10 Election Services Group10

11 Election Services Group11 How STV works: © Candidates win by receiving a number of votes equal to or greater than the victory threshold. In the first round of counting your ballot counts as one vote for your 1 st choice. If your 1 st choice wins with more votes than the winning threshold, then the “surplus” value of your ballot counts for your 2 nd choice candidate. * Surplus value is “transferred” to avoid votes being “wasted”

12 Election Services Group12 How STV works: Completing the ballot-count If all seats are not filled after transferring surplus ballot values, the last-place candidate is eliminated. Ballots cast for that eliminated candidate are then counted at full value for the next choice candidate listed on each ballot. If the next-choice candidate has won or been eliminated, your ballot will count for the next continuing candidate listed on your ballot. Last-place candidates are eliminated until all seats have been filled.

13 Election Services Group13 How it works: An STV example Suppose there are 99 voters for 9 seats, with 15 candidates running Victory threshold= 10 votes 9 10 votes = 90 voters represented (over 90% success)

14 Election Services Group14 STV tabulation example Each candidate is represented by a bin that can only hold 10 ballots. An STV tabulation starts with ballot- counters placing the voters’ ballots into the bins of the 1 st choice candidate listed on each ballot.

15 Election Services Group15 STV tabulation example Once a bin is full (containing 10 ballots), that candidate is elected. Any additional ballots would then TRANSFER to their next choice.

16 Election Services Group16 STV tabulation example Imagine 4 bins are full (and therefore 4 people elected) leaving 11 bins empty and needing to be filled.

17 Election Services Group17 STV tabulation example: After counting first choices Elected! 9 votes 4 votes 8 votes Elected! 2 votes 9 votes 1 vote 7 votes6 votes5 votes 4 votes Candidate 1Candidate 2Candidate 3 Candidate 4 Candidate 5 Candidate 6 Candidate 7 Candidate 8 Candidate 9 Candidate 10 Candidate 11 Candidate 12 Candidate 13 Candidate 14 Candidate 15 We’ve dealt all 99 ballots, and 4 bins are full. So 4 candidates have been elected and don’t need anymore votes. 11 candidates have partially filled ballots.

18 Election Services Group18 STV tabulation example We then take the ballots from the bin with the fewest votes, and redistribute those ballot to each voter’s next choice candidate. We continue eliminating the candidate with the fewest votes until we have 9 bins each filled with 10 votes.

19 Election Services Group19 STV tabulation example: Eliminate weakest candidate Elected! 9 votes 4 votes 8 votes Elected! 2 votes 9 votes 1 vote 7 votes6 votes5 votes 4 votes Candidate 1Candidate 2Candidate 3 Candidate 4 Candidate 5 Candidate 6 Candidate 7 Candidate 8 Candidate 9 Candidate 10 Candidate 11 Candidate 12 Candidate 13 Candidate 14 Candidate 15 First, we take the bin with only 1 vote and transfer it to the voter’s next choice. Then we take the candidate with the next fewest votes and transfer each ballot to the voter’s next unelected choice. Once a candidate hits 10 votes, they are elected and do not receive any more votes. We continue this process until we are left with 9 candidates elected with 10 votes each.

20 Election Services Group20 Elected! STV tabulation example: Eliminating other candidates Elected! 9 votes 4 votes 8 votes Elected! 2 votesDefeated! 7 votes6 votes5 votes 4 votes Candidate 1Candidate 2Candidate 3 Candidate 4 Candidate 5 Candidate 6 Candidate 7 Candidate 8 Candidate 9 Candidate 10 Candidate 11 Candidate 12 Candidate 13 Candidate 14 Candidate 15 First, we take the bin with only 1 vote and transfer it to the voter’s next choice. Then we take the candidate with the next fewest votes and transfer each ballot to the voter’s next unelected choice. Once a candidate hits 10 votes, they are elected and do not receive any more votes. We continue this process until we are left with 9 candidates elected with 10 votes each.

21 Election Services Group21 STV tabulation example: Final results Elected! Defeated!Elected! Defeated! Candidate 11 Candidate 12 Candidate 13 Candidate 14 Candidate 15 Candidate 6 Candidate 7 Candidate 8 Candidate 9 Candidate 10 Candidate 1 Candidate 2 Candidate 3 Candidate 4 Candidate 5

22 Election Services Group22 STV example: Summary There are 9 candidates elected with 10 votes each, representing at least 90 of the 99 voters. A bigger percentage than is ever likely to be represented than under FPTP.

23 Election Services Group23 Conclusions © STV is an efficient voting system which is very fair. The majority of voters will help to rank their #1 candidate. Voters can rank ALL candidates and their vote WILL count in getting at least one of their preferences elected, probably more.

24 Election Services Group24 In pairs or small groups, discuss the following questions and all take note of what you discuss: Use page of the sheets to help you.  Why do you think many people argue that STV is the fairest electoral system?  What arguments do you think could be used against STV?  What has the impact of STV been for Scotland?


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