Electoral Systems

Helpful cards to remember key terms and electoral systems with examples.

Electoral Systems - An Overview

Electoral systems are methods of translating votes into seats in an assembly or political office.

All systems fall into four categories:

  • Majoritarian
  • Plurality
  • Proportional
  • Mixed/Hybrid
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Majoritarian Systems

  • These systems require the winning candidate to aquire a majority vote to win the seat


  • Used in single member constituencies


  • The Alternative Vote is an example of a majoritarian system
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Plurality Systems

  • The winner requires a plurality of votes (one more than their rival)


  • Used in single member constituencies


  • First Past the Post is an example of a plurality system
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Proportional Representation

  • This covers many systems that aim to keep a close fit between number of votes and number of seats


  • Electoral formulas work out the number of seats gained in multi member costituencies


  • The Single Transferable Vote and Regional List system are examples of proportional representation
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  • This combines elements of plurality, majoritarian and proportional representation into one system


  • Some MPs are elected in single member constituencies, others are elected in multi member constituencies


  • The additional member system is an example of a mixed system
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First Past the Post

FPTP is used in the UK for electing members to the House of Commons. It is a plurality system in which the candidate with the most votes gains the seat. 


  • Simple to use, both when voting and when working out the winner
  • Produces strong, stable Governments; 2010 Con-Lib is only post-war coalition
  • Prevents more extreme parties from gaining seats
  • Keeps effective and clear link between voter and their representative


  • Creates a 2 party system, favours Labour and the Conservatives
  • Smaller parties are under represented
  • Votes are wasted, causes lower turnouts
  • Encourages tactical voting
  • Winner may not have support from the majority of voters = less legitimacy
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The Alternative Vote

Used to elect the Australian House of Representatives. Voters number candidates in order of preference. 1st preference votes are counted, if noone gains an overall majority the last place candidate is eliminated and their votes redistributed to the voters 2nd preference. This is repeated until a winner with a majority is produced.


  • The winner has the support of the majority of voters
  • The link between representative and constituency is retained


  • The winner is the least unpopular, not the most popular
  • Potentially less proportional than FPTP - If used in 1997 general election Labour would have a bigger majority and Lib Dems more seats than Cons
  • Potential for more extremist parties to gain seats
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The Supplementary Vote

A variant of AV. Used to elect the mayor of London and other directly elected mayors. Only the voters 1st and 2nd preferences are recorded. If no winner is decided after the first round, all but the top two candidates are eliminated and their votes redistributed. The candidate with the highest total is then elected.


  • Broad support must be gained by the winner
  • Keeps extreme parties out


  • The winning candidate does not need a majority
  • If used for general elections, it would deliever a disproportionate outcome
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The Regional List

Used to elect members of European Parliament from England, Scotland and Wales. Representatives are elected in large multi-member constituencies. Parties draw up a list of candidates in order of who they want elected. Seats are then allocated proportionally according to number of votes gained by each party or independent.


  • A high degree of proportionality, especially in larger regions
  • Parties can increase numbers of women and ethnic minority candidates


  • Parties can use lists to favour candidates that support the leadership
  • Weak link between representative and constituency
  • Voters can't vote for a favoured candidate.
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Single Transferable Vote

This is used in Northern Ireland for elections to the NI Assembly and European Parliament. Representatives are elected from large multi-member constituencies. Voters number candidates in order of preference and can number as many or few as they like. A candidate must achieve the 'Droop quota' to be elected. Any votes over the quota are redistributed. If noone reaches the quota after the first round, the last place is eliminated and votes redistributed.


  • Only parties with 50% of the vote can form a government
  • Delivers proportional outcomes and ensures votes are of very similar value
  • Voters have wide choice of candidates, including ones from the same party


  • Likely to produce coalitions
  • Less accurate in translating votes proportionally than AMS or list systems
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The Additional Member System

AMS is a mixed/hybrid system (part FPTP part PR). Used to elect Welsh Assembly and Scottish Parliament. Electors vote twice; once for a candidate to represent a single member constituency and once for a party in a multi member constituency.


  • Keeps strong link between representative and constituency while retaining a fairer outcome
  • Votes are less likely to be wasted
  • Voters have lots of choice, they can essentially vote for 2 different parties


  • Smaller parties can still be under-represented
  • Assemblies have members with constituency responsibilities and members without them
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Old Sir


A clear, useful set of revision cards for any student looking for a concise overview. These could be used as a starting point for further revision involving the attachment of examples or case studies in order to gain marks at AO2, (analysis and evaluation).

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