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: Totalvalidvotes/(Numberofseats+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.
