Additional Member System

The Additional Member System (AMS) is a branch of voting systems in which some representatives are elected from geographic constituencies and others are elected under proportional representation from a wider area, usually by party lists. Voters have two votes, one for the party and the second for the candidate in a constituency. The constituency representatives are generally elected under the first-past-the-post voting system. The party representatives are elected by a party vote, where the electors vote for a political party, and usually not directly for an individual. The particular individuals selected come from lists drawn up by the political parties before the election, at a national or regional level.

Variations of the AMS have different ways of determining how many party representatives each party is entitled to. The main difference between systems is whether the constituency representatives are counted when party representatives are allocated.

• Under the Mixed Member Proportional (MMP) or Top-Up (compensatory) system, the aim is either for the party's total number of representatives, including constituency representatives, to be proportional to its percentage of the party vote, or for the allocation of additional party seats to offset some or all of the disproportionate result in the constituencies. The party vote largely determines the number of representatives the party has in the assembly.
• Under the Parallel Voting or Supplementary Member (SUP) system, the party seats are allocated proportionally within themselves, without consideration of the so any constituency seats the party may have won are additional.
• Under the French proportional system designed to produce a strong majority, half the seats are given proportionally between party lists and the other half given to the list with a plurality, thus ensuring that a single list wins well over half the seats.

Parallel Voting is among the most common variation among voting systems of the world. Small parties will generally win more seats under MMP than SUP unless there is a threshold of exclusion, such as the 5% or 3 constituencies threshold in Germany, or the 5% or 1 constituency seat threshold in New Zealand.

[edit] Criticisms

Since the majority party and its coalition partners in an election are likely to win a large number of proportional seats, additional member systems hand additional political power to the leader of government at the expense of regional directly elected representatives. "Party List" candidates may become figureheads for the party leadership. While minority parties gain seats under additional member systems, majority parties may lose diversity, leading to power concentrating in the hands of fewer individuals than under a Plurality voting system.

[edit] See also

• Leveling seat
• List of democracy and elections-related topics
• Voting system

[edit] References

This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed. (December 2006)