Electoral systems

Electoral systems. First past the post: The country is divided into constituencies (which each have one representative). Each voter is given a list of candidates standing in their constituency and they vote for one. The candidate who gets the most votes wins the constituency. Supplementary vote: The country is divided into constituencies (which each have one representative). Each voter is given a list of candidates standing in their constituency and they designate a first and second preference. If any candidate wins over half of first preference votes, then they win the constituency. If not, then every candidate but the two with the most first preference votes is eliminated and their voters’ second preference votes are redistributed: whoever then has the most votes wins the constituency. Additional member system: The country is divided into both constituencies (which each have one representative) and regions (which each have multiple representatives). Each voter is given a list of candidates standing in their constituency and a list of (mostly) parties standing in their region, from which they can vote for one on each list. The candidate who gets the most votes in each constituency wins that constituency. For the regions, candidates are allocated seats in proportion to the regional vote, while also taking into account the constituency representatives already elected. Single transferable vote: The country is divided into regions (which each have multiple representatives). Each voter is given a list of candidates standing in their region and they can rank as many as they want in order of preference. The candidate who gets the most votes in each constituency wins that constituency. Any candidate who reaches the vote quota is elected and if there are no empty seats left, the process ends. An elected candidate’s excess votes (the votes that they got on top of the vote quota) are proportionally allocated to the remaining candidates in accordance with the vote. Then, if no other candidate has reached the vote quota, the candidate with the fewest votes left is eliminated and their votes are proportionally allocated to the remaining candidates in accordance with the vote. Then, if no candidate has reached the vote quota or if the number of candidates and empty seats left are not equal (if they are, all remaining candidates are elected), the candidate with the next fewest votes left is eliminated and so forth.
Evaluating electoral systems. There are a lot of electoral systems out there and even more measures to evaluate them against — here are seven: Accessibility: An electoral system should be easy to understand and, therefore, use; Effective government: Each election should produce a clear winner (probably a majority government), which can ‘get stuff done’; Help on hand: Constituents should have an obvious representative to turn to for assistance once the election is over; Every vote counts: Every vote should stretch as far as it can and a representative should not be able to win with just a plurality of votes; Individual accountability: Individual representatives should have a clear mandate and be easily rejected when the next election comes around. Proportionality: A political party’s overall number of votes should match their overall number of seats. Rejecting the fringe: An electoral system should make it harder for extremist candidates to win.
Electoral systems and effective government. Elections usually result in one of four types of government: majority, minority, coalition or confidence and supply and the following charts set out the results that general elections and devolved elections which use electoral systems have produced since 1997. United Kingdom: 2019 (FPTP): Conservative majority; 2017 (FPTP): Conservative-DUP confidence and supply; 2015 (FPTP): Conservative majority; 2010 (FPTP): Conservative-Liberal Democrat coalition; 2005 (FPTP): Labour majority; 2001 (FPTP): Labour majority; 1997 (FPTP): Labour majority. Scotland: 2021 (AMS): SNP-Green coalition; 2016 (AMS): SNP minority; 2011 (AMS): SNP minority; 2007 (AMS): SNP minority (with Green support over ministerial appointments, but not confidence and supply); 2003 (AMS): Labour-Liberal Democrat coalition; 1999 (AMS): Labour-Liberal Democrat coalition. Wales: 2021 (AMS): Labour minority; 2016 (AMS): Labour-Liberal Democrat-Independent coalition; 2011 (AMS): Labour minority; 2007 (AMS): Labour-Plaid Cymru coalition; 2003 (AMS): Labour minority; 1999 (AMS): Labour-Liberal Democrat coalition. Northern Ireland: 2022 (STV): No executive formed (yet); 2017 (STV): DUP-Sinn Féin led coalition; 2016 (STV): DUP-Sinn Féin led coalition; 2011 (STV): DUP-Sinn Féin led coalition; 2007 (STV): DUP-Sinn Féin led coalition; 2003 (AMS): No Executive formed; 1998 (AMS): UUP-SDLP led coalition.
Electoral systems and proportionality. First past the post is used as the electoral system in UK general elections, but the Electoral Reform Society has modelled how the result of the 2019 general election in Great Britain might have looked if additional member system or single transferable vote were used; this resource also sets out which electoral systems are used in the UK. 2019 GB general election: The Conservative Party won 44.7% of votes, 57.8% of seats under first past the post and is projected to have won 44.9% and 49.4% of seats under alternative membership system and single transferable vote, respectively. The Labour Party won 33.0% of votes, 32.1% of seats under first past the post and is projected to have won 29.7% and 35.0% of seats under alternative membership system and single transferable vote, respectively. The Liberal Democrats won 11.8% of votes, 1.7% of seats under first past the post and is projected to have won 12.5% and 9.3% of seats under alternative membership system and single transferable vote, respectively. The Scottish National Party won 4.0% of votes, 7.6% of seats under first past the post and is projected to have won 4.1% and 4.7% of seats under alternative membership system and single transferable vote, respectively. Plaid Cymru won 0.5% of votes, 0.6% of seats under first past the post and is projected to have won 0.8% and 0.8% of seats under alternative membership system and single transferable vote, respectively. The Green parties won 2.8% of votes, 0.2% of seats under first past the post and are projected to have won 6.0% and 0.3% of seats under alternative membership system and single transferable vote, respectively. The Brexit Party won 2.1% of votes, 0% of seats under first past the post and is projected to have won 1.9% and 0.5% of seats under alternative membership system and single transferable vote, respectively. Other parties (excluding the Speaker of the House of Commons) won 1.1% of votes, 0.0% of seats under first past the post and are projected to have won 0.0% and 0.0% of seats under alternative membership system and single transferable vote, respectively. Electoral systems used in the UK: General elections: first past the post; Devolved elections in Scotland and Wales: additional member system; Devolved elections in Northern Ireland: single transferable vote; local elections in England: first past the post (except AM elections, where additional member system is used); Local elections in Scotland, Wales and Northern Ireland: single transferable vote (except PCC elections in Wales, where first past the post is used). Supplementary vote was used in mayoral and PCC elections until the Elections Act 2022.