Electoral systems (in brief)

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Majoritarian, Plurality and Proportional

  • Majoritarian

The winning candidate must secure an absolute majority of the vote (eg. 50%). Majoritarian systems usually require single-member constituencies. FPTP is sometimes described as majoritarian (although this is not strictly accurate). Other examples are SV and AV

  • Plurality

Plurality systems are similar to majoritarian systems, in that they need single-member constituencies and are non-proportional. Plurality systems, however, do not require candidates to get a majority- they just need to get more votes than other candidates. FPTP is an example of this- candidates do not need to get an outright majority and can win on as little as 20% of the vote.

  • Proportional

Proportional representation (PR) covers many systems such as regional list, STV and AMS. They traditionally use multi-member contituencies and political formulas (such as the D'Hondt formula- a simulation of which is shown here http://icon.cat/util/elections).

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  • The electoral system used in the UK
  • A simple plurality system
  • In simple terms, the person who gets the most votes wins. The electorate place a cross ('X') in the candidate they want to vote for. The system relies on constituencies which all have separate representatives.
  • In the UK, there are 650 constituencies, all containing around 70,000 electors


  • usually provides a clear winner
  • simple to understand and operate, 
  • usually produce strong government, 
  • provide a strong link between parliament and constituencies 


  • disproportional outcomes (for example a party winning by 1 vote)
  • limited choice
  • lots of wasted votes
  • Discriminatory to smaller and third parties
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Alternative Vote (AV)

  • Representatives elected in single-member constituencies
  • voters number their choices, with '1' being most preferred. If no candidate gets a majority first time, the lowest-placed candidate is eliminated and second choices are used.
  • the process continues until one candidate reaches 50% of the vote.
  • a referendum over the use of AV in the UK was taken in 2011. Voters rejected its use.


  • representatives are elected by the majority
  • the winning candidate must achieve broad support
  • there is a strong link between representatives and their constituents 
  • no wasted votes so often higher turnout


  • It is still not a proportional system, as candidates rarely get a majority in the first round.
  • the candidate who wins is often people's second choice, meaning that Liberal Democrats and other smaller parties would get an unproportional amount of seats.
  • This also means it is easier for small extremist parties to get into power. 
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Supplementary Vote (SV)

  • A variant of AV, used to elect the mayor of London
  • The elector has one vote and records only their first and second choices on paper. If no candidate wins with a majority in the first round, all but the top two candidates are eliminated and second preference votes are used to decide the winner. 


  • The winner must have broad support from the electorate
  • It is more proportional than First-past-the-post
  • It ensures that small extremist parties do not get through


  • The winning candidate does not have to have an overall majority- he can win by second preference votes. 
  • It is still not very proportional, especially on large scale general elections
  • It is geared towards the top two parties- smaller and third parties rarely get enough votes not to be eliminated in the first round. 
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Regional List

  • Fully proportional representation (it is also known as PR, proportional representation), used in MEP elections since 1999
  • representatives elected in large multi-member constituencies (in the MEP elections this means 11 regions with between 3 and 10 MEP's in each). 
  • Political parties draw up the lists of candidates
  • In closed list PR, electors can only vote for the party and the one candidate they put forward. In open list, the electorate can also pick which candidate they want from the party.
  • seats are allocated proportionally using the D'Hondt formula.


  • high degree of proportionality, and open list gives very good voter choice
  • Political parties can use closed list PR to increase the number of minorities being elected


  • Closed list PR limits voter choice and puts too much power with the political party
  • the MP-constituent link is weakened by large multi-member constituencies 
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Single Transferable Vote (STV)

  • used in northern Ireland, where proportionality has reached a record high of 8%. Australia has also experimented with STV, but decided on using a hybrid system
  • representatives are elected in large multi-member constituencies.
  • Voters number the candidates they want elected, e.g 1.  2. 3. etc.
  • a candidate must achieve the droop quota (total of votes/ seats available +1)  if no candidate achieves this the bottom candidate is eliminated and the votes redistributed, until one candidate fulfils the quota.


  • It ensures a very proportional result
  • candidates must have a majority to win.
  • there is a large amount of voter choice.


  • the system is less proportional than PR and AMS
  • large multi-member constituencies weaken the link between MP and constituents
  • Donkey votes become increasingly common- 5% of the votes in Australia in 2007 were donkey votes (numbering the candidates in the order they appeared)
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Additional Member System

  • A hybrid electoral system used to elect the Scottish Parliament and Welsh Assembly since 1999.
  • It is also used for general elections in Germany.
  • the system is a mixture of FPTP and PR. In Scotland, 57% of MSP's are elected using FPTP in single member constituencies, and the additional 43% are elected using party list and the D'hondt formula in larger, multi-member constituencies. Voters have two votes- one for their favourite candidate locally, and one for their favourite party regionally.


  • It combines the MP constituency link of FPTP and proportionality of PR
  • less wasted votes and a more proportional outcome.
  • Voters have a much larger choice and can split-ticket vote- 1/5 scots spit-ticket in elections


  • Conflict between local and regional MPs
  • Can be very confusing- in the 2007 Scottish Parliament election 146000 votes had to be discarded due to spoilt ballot papers.
  • There are still the disadvantages of PR and FPTP such as significant party control. 
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