ELECTORAL SYSTEMS

• A candidate must secure an absolute majority of the vote to win; in a pluraltiy system, they need to only win more votes than the second-placed candidate. 

• Candidates are elected in single-member constituencies. 

• The outcome is not proportional - large parties take a higher proportion of seats than their share of the vote merits, while smaller parties are often under-represented. 

• The systems tend to produce single-party governemnts with working parliamentary majorites. 

• Candidates are elected in multi-member constituencies.

• Electoral formulas are used to allocate seats in the legislative assembly. 

• The outcome is proportional - there is a close fit between the share of the vote won by a party and the share of the seats it is allocated.

• The systems tend to produce coalition governments as no single party wins a majority of the seats. 

FPTP

• Used in general elections to the House of Commons

Key Features:

• Plurality system

• Single-member constituencies

• Disproportional outcome

SUPPLEMENTARY VOTE

• Used to elect the Mayor of London and Police and Crime Commissioners.

KEY FEATURES:

• Majoritarian system

• Used to elect individuals

• Voters record two preferences

• Winning candidate has a majority

REGIONAL LIST

• Used for European Parliament elections in Great Britain, List seats for the Scottish Parliament, Welsh Assembly and London Assembly. 

KEY FEATURES:

• Proportional representation system

• Electors vote for a party in multi-member regions

• Proportional outcome

SINGLE TRANSFERABLE VOTE

• Used for Assembly, local and European Parliament elections in Northern Ireland, and local elections in Scotland and Northern Ireland.

KEY FEATURES

• Propotional representation system

• Electors rank candidates in mutli-member costituencies

• Proportional outcome 

ADDITIONAL MEMBER SYSTEM

• Used for the Scottish Parliament, Welsh Assembly and London Assembly. 

KEY FEATURES

• Mixed electoral system 

• Electors cast two votes - one for a constituency candidate elected by FPTP and one for a regional list candidate elected by closed list PR

• List candidates are allocated to parties on a corrective ebassi to produce a proportional outcome.