Overview of Electoral Reform

FPTP / SMPS

• Used in Westminster and English and Welsh local elections

• Voter chooses a candidate

• Winning candidate requires plurality to win

Supplementary Vote

• Used in mayoral elections in UK and Police and Crime Commissioners in the UK from 1999-2024

• Voters have two preferences

• If no candidate gets more than 50%, only top two are eligible

• Second preferences are then added to first preferences to see who is elected

• Majoritarian System

• Example: London 2021; Sadiq Khan and Shaun Bassey 

Proportional Representation 

• Type of electoral system

• Attempts to ensure proportion of votes a party receives is roughly equal to percentage of seats. 

Additional Member System

• Used in Scotland, Wales, and in the elections to the Greater London Authority

• Voters have two votes: one for constituency member; one for party list

• Constituency member decided by Plurality System

• Party list votes allocated on proportionality 

For example, in Scottish Parliament Election in 2021 - SNP had 44% of vote, and got 64 seats, one short of a majority.

Single Transferable Vote

• Used in NI Assembly elections

• Used in Israel

• Multi-member constituencies represented by 5-7 MPs 

• Voters rank all candidates in order of preference

• Successful candidates must meet a minimum quota to be elected.

How STV is calculated?

• Number of valid votes cast in the election divided by the total number of seats to be filled plus one, plus one again