MMP – Mixed Member Proportional

This is the system we currently use to elect our Parliament.

There are 120 Members of Parliament (MPs). There are 70 electorates, including the Maori electorates. Each elects one MP, called an Electorate MP. The other 50 MPs are elected from political party lists and are called List MPs.

Each voter gets two votes. The first vote is for the political party the voter chooses. This is called the party vote and largely decides the total number of seats each political party gets in Parliament.

The second vote is to choose the MP the voter wants to represent the electorate they live in. This is called the electorate vote. The candidate who gets the most votes wins. They do not have to get more than half the votes.

Under current MMP rules, a political party that wins at least one electorate seat OR 5% of the party vote gets a share of the seats in Parliament that is about the same as its share of the party vote. For example, if a party gets 30% of the party vote it will get roughly 36 MPs in Parliament (being 30% of 120 seats).  So if that party wins 20 electorate seats it will have 16 List MPs in addition to its 20 Electorate MPs.

Coalitions or agreements between political parties are usually needed before Governments can be formed.

MMP in Detail

This is the system we currently use to elect our Parliament.

Types of MPs?

There are two types of MPs – those elected from electorates and those elected from party lists.

The country is divided into 70 electorates, each electing one MP. They are called Electorate MPs and currently represent

  • 16 South Island general electorates
  • 47 North Island general electorates
  • 7 Maori electorates

The other MPs in Parliament are elected from political party lists and are called List MPs.

How would you vote?

Each voter has two votes.

The first vote is for the political party the voter chooses. This is called the party vote. Voters put a tick next to the name of the party for which they wish to vote.

Each political party’s share of all the seats in Parliament is about the same as its share of the party vote.

The second vote is called the electorate vote and is used to choose the Electorate MP the voter wants to represent the electorate they live in. Voters put a tick next to the name of the candidate for whom they wish to vote. The candidate who gets the most votes wins. They do not have to get more than half the votes.

How are MPs elected?

Under current MMP rules, a political party is entitled to a share of MPs that’s about the same as its share of the party vote if it reaches one of two thresholds (sometimes called clearing one of two "hurdles"). To meet these thresholds or hurdles, a political party must win:

    EITHER at least 5% of the nation-wide party vote;
    OR at least one electorate seat.

A formula – called the Sainte-Laguё formula – is used to determine the total number of seats each party is entitled to in Parliament (more details about how the formula works can be found here.

A political party’s total number of seats in Parliament is filled with a mix of Electorate MPs and List MPs.

The Electorate MPs are elected using the First Past the Post voting system (FPP). The candidate who gets the most votes wins. The winning candidate does not have to get more than half the votes. (For more information about this, see the section on FPP.)

The rest of a party’s MPs are elected from the party’s list. The number of List MPs each party receives is the difference between a party’s total allocation of seats in Parliament and its number of Electorate MPs.

For example, if a party gets 30% of the party vote it will get about 36 MPs in Parliament (being 30% of 120 seats). So if that party wins 20 electorate seats it will have 16 List MPs in addition to its 20 Electorate MPs.

If a party crosses the 5% party vote threshold but, at the same time, wins no electorate seats, it is still entitled to a share of all the seats in Parliament. For example, if a party wins 10% of the party votes and no electorate seats, all its 12 MPs (10% of 120) will be List MPs elected from the party list in the order they are ranked by the party.

Sometimes a party's share of the party vote entitles it to a number of seats in Parliament that is smaller than the number of its Electorate MPs.

When this happens that party will neither have electorate seats taken away from it, nor be allocated any List MPs. Instead, for the life of the Parliament concerned there will be more than 120 MPs in Parliament. This is called an overhang and has happened twice: from 2005-08 there were 121 MPs, and in the 2008-11 Parliament there have been 122 MPs.

What would Parliament look like?

MMP is classified as a proportional representation voting system. This is because the overall result closely mirrors the party vote.

The share of seats a political party wins in Parliament is about the same as its share of the party vote. This applies both to big parties and to small parties if they qualify for a share of the seats in Parliament by achieving one of the two thresholds.

The main features of MMP are illustrated in the results of the last two Parliamentary elections in New Zealand.

mmp1.png

In 2005, all the parties that qualified for seats in Parliament won a share of the seats that was about the same as their share of the party votes. For example, the Labour Party won 41.1% of the party votes and 41.3% of the seats in Parliament. Likewise, the New Zealand First party won 5.7% of the party votes in 2005 and 5.8% of the seats in Parliament.

In 2008, many of the parties represented in Parliament had a slightly higher share of the seats than their share of the nation-wide party votes. This was partly because the party that won the fourth-highest share of the party votes (New Zealand First) failed to reach either the 5% party-vote threshold or the one-seat threshold and thus won no seats in Parliament. In 2008 the Green Party did not win any electorates seats.

However, because the Green Party (with 6.7% of the party votes) had cleared the 5% party-vote threshold, it was entitled to 9 List seats – 7.4% of all the seats in Parliament.

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What type of government is usually formed?

Under MMP, coalitions or agreements between political parties are usually needed before Governments can be formed.

For example, after the 2005 election in New Zealand, the largest party in Parliament – Labour – formed a government after signing a coalition agreement with the Progressive Party and signing "confidence and supply" agreements with the New Zealand First and United Future parties.

Similarly, after the 2008 election the largest party in Parliament – National – formed a government after negotiating "confidence and supply" agreements with the ACT, Maori and United Future parties.

Where is MMP used?

MMP has been used for parliamentary elections in New Zealand since 1996. It has been used for federal parliamentary elections in Germany for more than sixty years. MMP is also used for elections to all the state parliaments in Germany, as well as for elections to the Scottish Parliament and the Welsh Assembly.

What are other names for Mixed Member Proportional (MMP)?

In the United Kingdom, MMP is sometimes known as AMS (which stands for Additional Member System) . Political scientists have classified MMP as an example of a two-tier compensatory proportional representation voting system.

 

Last updated: 20 October 2015