The Additional Member System (AMS) is a mixed electoral system used in various elections in the United Kingdom, including those for the Scottish Parliament, the Welsh Senedd, and the London Assembly. AMS combines two voting methods: the first-past-the-post (FPTP) system and the proportional representation (PR) system, specifically the regional list method. This hybrid approach aims to balance the direct accountability of individual representatives with the proportionality of party representation.
How the Additional Member System works
Under AMS, voters are given two votes:
Constituency vote: The first vote is for a candidate to represent the voter’s local constituency. This part of the system uses the FPTP method, where the candidate with the most votes in the constituency wins the seat.
Regional vote: The second vote is for a political party or an independent candidate in a larger regional area. Seats are then allocated to parties based on the proportion of votes they receive, using the d’Hondt method to ensure a more proportional representation.
Seat allocation
Constituency seats: These are won by individual candidates in the traditional FPTP manner.
Regional seats: After the constituency seats are filled, the regional votes are used to allocate additional seats to parties that have been underrepresented by the FPTP results. This helps to correct any disproportionality created by the FPTP system.
For example, if a party wins many constituency seats but receives a lower percentage of the overall regional vote, they might not receive additional regional seats. Conversely, a party with fewer constituency seats but a higher percentage of the regional vote may receive additional regional seats to balance representation.
More Like This: First Past The Post voting system
Advantages of Additional Member System
Proportional representation: AMS addresses one of the main criticisms of the FPTP system—its tendency to produce disproportional results where the number of seats won by a party does not accurately reflect the percentage of the vote they received. By incorporating proportional representation through the regional list, AMS ensures that smaller parties have a better chance of being represented.
Local representation: Despite its proportionality, AMS retains a strong element of local representation through the FPTP element. Voters still have a direct link to a local constituency representative who is accountable to their specific area.
Reduces “wasted” votes: In purely FPTP systems, votes for losing candidates often feel “wasted.” In AMS, even if a voter’s preferred candidate doesn’t win in their constituency, their party vote still contributes to the overall proportionality in the regional seats.
Encourages political diversity: Smaller parties that might struggle to win individual constituencies can still gain seats through the regional vote, encouraging a more diverse political landscape and ensuring a wider range of voices in the legislative process.
Disadvantages of Additional Member System
Complexity: One of the main criticisms of AMS is that it can be confusing for voters. With two votes and a mix of electoral methods, it can be challenging for voters to understand how their votes translate into seats, potentially leading to voter disengagement.
Potential for overhang seats: In some cases, a party may win more constituency seats than it would be entitled to under a purely proportional system. This can lead to an “overhang,” where the overall seat distribution still skews towards larger parties, albeit less than in FPTP alone.
Tactical voting: AMS can still encourage tactical voting, particularly in the constituency vote. Voters might vote strategically for a candidate they believe has the best chance of winning rather than their preferred candidate, especially in closely contested constituencies.
Two types of representatives: AMS creates two classes of representatives—constituency representatives and regional list members. This can lead to confusion about the roles and accountability of each type, and may result in tensions between them.
Regional list selection: The selection of candidates for the regional list can be criticized for being less transparent and more controlled by party leadership, potentially reducing the overall accountability of regional representatives to the electorate.
Follow us on Twitter @BeInTheKnow_UK
