Additional member System

• Where is AMS used?

  Elections to the Scottish Parliament, Welshy Assembly and Greater London Assembly
• How does AMS work?

  Voters have two votes. One for constituency representatives elected using FPTP. The other is used for a party list which uses multi-member regional constituencies, introducing an element of proportional representation
• What does the party list element do?

  ’Corrects’ the constituency element by using the D’Hondt formula to determine how many members a party should be allocated from the lists
• What does the D’Hondt formula do?

  Gives party who were underrepresented in the constituency element greater representation
• Example of the system being more proportional compared to FPTP

  In 1999 Scottish Parliament election, the Conservative Party won 0 constituency MPs despite getting around 16 % of the vote, but won 18 additional members to correct this, leading them receiving 14 % of seats overall
• What does AMS ensure remains?

  MP - constituency link
• Voters have a wider choice than under FPTP

  They can vote for a ‘split ticket : voting for one party for a representative and another for their top-up vote
• In the 2021 Scottish Parliament election, the Greens won just 1.29 % of the consti votes but 8.12 % of the top-up votes and got 8 seats. The Greens intentionally stands few consistency candidates in order to benefit from the top up element
• Disadvantage 1: creates two different types of members 


  Some MPs have constituency responsibilities and some without. There is little evidence, however, that the second category is seen as having less legitimacy
• A closed list system is used

  Meaning that the party leadership ranks candidates in order on the list. It can use this power to limit chances of dissident members of the party being elected, therefore giving the party a great amount of power and making it harder for parties to be broad churches
• C/A: a closed list is used

  This could be seen as an advantage because parties can ensure good direct representation of disadvantaged groups such as women and ethnic minorities. For example, zipping is often used (lists alternate between male and female)
• AMS is more likely to lead to minority and coalition governments, which can be seen as weak. In the 6 Scottish governments since devolution, 3 have been coalition and 2 have been minority governments
• Why is AMS used in elections to the Scottish Parliament, Welsh Assembly and Greater London Assembly?

  Chosen as a compromise that would result in a. broadly representative parliament but not involve the radical change of STV (which the LibDems advocated for) and maintain local representation
• What did Labour expect AMS to do?

  Enable it to play a part in government in Scotland and this proved correct until 2007