Proportional Systems and Electoral Reform Debates in the UK
Proportional and mixed electoral systems aim to make a party's share of seats reflect its share of votes more closely than First Past the Post does.
Before you start
Make sure you're comfortable with these topics first:
Method
- Learn how the Additional Member System (AMS) combines FPTP constituency seats with regional list seats allocated to correct disproportionality, and where it is used, the Scottish Parliament and the Senedd.
- Learn how the Single Transferable Vote (STV) works in multi-member constituencies, with voters ranking candidates and surplus/eliminated votes transferred, and where it is used, the Northern Ireland Assembly and Scottish local elections.
- Learn how the Supplementary Vote (SV) worked where it was used, with voters marking a first and second choice, and how it differed from AMS and STV in still using single-member contests.
- Learn about the 2011 UK referendum on the Alternative Vote, a different, non-proportional system proposed to replace FPTP for the Commons, including that voters rejected the proposed change.
- Learn the trade-offs each proportional or semi-proportional system involves, such as AMS creating 'two classes' of representative (constituency and list), or STV producing very large, multi-member constituencies.
- Learn the main arguments for and against introducing a more proportional system for UK general elections, covering proportionality, government stability, and the constituency link.
- For 'assess'/'evaluate' questions comparing systems, weigh a genuine strength against a genuine weakness of the system in each paragraph, and reach a distinct judgement in each, rather than only listing systems' features.
Worked example
In a Scottish Parliament region, the regional list seats are allocated using the additional member system's correction method after constituency results. Party X has already won 6 of the region's 9 constituency seats despite securing only 30% of the regional list vote. Explain, in general terms, how the additional member system's list seats respond to this kind of mismatch.
- Note the mismatch: Party X has won a large share of constituency seats, 6 of 9, from a much smaller share of the regional vote, 30%.
- Recall that AMS allocates regional list seats using a formula that takes each party's constituency seats already won into account, not just its list vote share on its own.
- Apply the principle: because Party X already holds many constituency seats relative to its vote share, the formula makes it comparatively harder for Party X to win further seats from the regional list.
- Apply the principle to other parties: parties that won few or no constituency seats relative to their regional vote share are comparatively more likely to be allocated list seats.
- State the overall effect: the list seats are designed to move the region's overall result closer to proportionality, correcting for the disproportionality the constituency (FPTP) element alone would produce.
Practice questions
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Q1Which electoral system combines FPTP constituency seats with regional list seats, and where in the UK is it used?Show answer
Answer: The Additional Member System (AMS), used for the Scottish Parliament and the Senedd (Welsh Parliament).
Q2What is distinctive about how voters cast their ballot under the Single Transferable Vote (STV)?Show answer
Answer: Voters rank candidates in order of preference in multi-member constituencies, rather than marking a single choice.
Q3Where in the UK is STV used?Show answer
Answer: The Northern Ireland Assembly and Scottish local council elections.
Q4What did voters decide in the 2011 UK referendum on the Alternative Vote?Show answer
Answer: They voted to reject the Alternative Vote and keep First Past the Post for UK general elections.
Q5Give one criticism of the Additional Member System.Show answer
Answer: It can create two classes of representative, constituency members and regional list members, who may be seen as having different levels of legitimacy or accountability.
Q6Give one advantage proportional systems generally have over First Past the Post.Show answer
Answer: Seat shares tend to more closely reflect vote shares, so smaller parties with evenly spread support are more fairly represented.
Q7Give one disadvantage proportional systems can have compared with First Past the Post.Show answer
Answer: They are more likely to produce a coalition or minority government, which can mean less stable government and post-election deals that voters did not directly vote for.
Q8Name the electoral system used to elect the London Mayor and police and crime commissioners in England and Wales before both switched to First Past the Post.Show answer
Answer: The Supplementary Vote (SV).
Exam-style questions
Written in the style of a A Level Politics exam paper, with a full mark scheme.
Using an example, explain one advantage of a proportional or semi-proportional electoral system over First Past the Post.
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'The UK's experience of proportional and semi-proportional systems shows they should replace First Past the Post for general elections.' Analyse and evaluate this statement.
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