Single Transferable Vote (STV) and Supplementary Vote (SV)

Single Transferable Vote (STV)

STV is used in Northern Ireland Assembly elections to facilitate power-sharing.

Definition: STV is a form of proportional representation using ranked voting in multi-member constituencies.

Key features:

• 18 regions with 6 representatives each
• Voters rank candidates in order of preference
• Candidates must reach a 'Droop quota' to be elected

Vocabulary: The Droop quota is calculated as: $Total valid votes / (Number of seats + 1)$ + 1

Effects on UK elections:

• Promotes multi-party systems and coalition governments
• Reduces the number of 'safe seats'
• Produces more proportional results

Advantages:

• Highly proportional results
• Offers greater voter choice
• Improves representation of diverse views

Disadvantages:

• More complex system
• Weakens the constituency link
• Can make single-party governments unlikely

Highlight: STV allows voters to choose between and within parties, offering a high degree of voter choice.

Supplementary Vote (SV)

SV is used to elect the Mayor of London every four years.

Definition: SV is a preferential voting system where voters express a first and second preference.

Key features:

• Two columns for first and second preferences
• If no majority after first preferences, top two candidates remain
• Second preferences are then redistributed

Effects on UK elections:

• Tends to maintain a two-party system
• Usually results in strong, single-party leadership
• Can lead to tactical voting

Advantages:

• Ensures a majority result
• Offers some voter choice
• Relatively simple to understand

Disadvantages:

• Can still lead to two-party dominance
• May produce 'false majorities'
• Many votes can be wasted

Example: In the 2016 London mayoral election, around 400,000 voters did not express a second preference, potentially reducing their influence on the final result.

This comprehensive guide to electoral systems in UK Politics provides essential information for students studying A-level Politics, particularly those following the Edexcel or AQA syllabi. Understanding these systems is crucial for analyzing voting behaviour and the complexities of UK elections.

First Past the Post (FPTP) and Additional Member System (AMS)

First Past the Post (FPTP)

FPTP is the primary electoral system used for UK general elections.

Definition: FPTP is a plurality voting system where the candidate with the most votes in each constituency becomes the MP.

Key features:

• 650 constituencies with approximately 70,000 people each
• Party with the most MPs forms the government
• Typically results in a two-party system

Effects on UK elections:

• Often produces strong, single-party governments
• Creates 'safe' and 'swing' seats
• Can lead to disproportionate results

Example: In 1997, Labour won 43% of the vote but 63% of the seats, demonstrating the 'winner's bonus' effect of FPTP.

Advantages:

• Simple and easy to understand
• Promotes strong governments
• Maintains MP-constituency link

Disadvantages:

• Lack of voter choice
• Unequal vote value
• Disproportionate results

Highlight: FPTP often results in a 'winner-takes-all' scenario, which can lead to underrepresentation of smaller parties.

Additional Member System (AMS)

AMS is used in Scottish Parliament and Welsh Assembly elections.

Definition: AMS combines FPTP with proportional representation, using two separate ballots - one for constituency MPs and one for regional lists.

Key features:

• Voters have two votes: constituency and regional
• Uses d'Hondt formula for allocating regional seats
• Aims to balance local representation with proportionality

Effects on UK elections:

• Tends to produce multi-party systems
• More likely to result in coalition governments
• Maintains some safe seats in constituency votes

Advantages:

• More proportional results
• Allows for split-ticket voting
• Encourages broader representation

Disadvantages:

• More complicated system
• Less likely to produce single-party governments
• Creates two tiers of representatives

Vocabulary: The d'Hondt formula is a mathematical method used to allocate seats in proportional representation systems.