NZ Election 2020: How New Zealand's MMP electoral system works

Here's how MMP works in Aotearoa.
Here's how MMP works in Aotearoa. Photo credit: Getty.

From 7pm on Saturday night, the Electoral Commission will begin releasing results for the 2020 general election and we will start to see how our next Parliament may look. 

But how is a Parliament made up in New Zealand, and what decides which MPs get a seat, and who misses out?

Here's a look at our electoral system of Mixed Member Proportional or MMP:

Under MMP, every eligible voter has two votes - one for a candidate in their electorate and one for a party. An electorate is an area of New Zealand the voter is registered in, of which there are 72 in Aotearoa.

The electorate vote is for the candidate the voter wants to represent their area in Parliament. These candidates are typically from parties, but could be independent. The candidate with the most votes becomes its Member of Parliament (MP) and secures a seat. 

The party vote is for the group of politicians the voter supports. The percentage of the vote a party receives largely determines how many seats the party gets in total in our 120-seat Parliament. That means seats are allocated on the share of the vote that counts. 

A party must receive more than 5 percent of the party vote or win an electorate to gain any seats in Parliament. 

For example, a party with 30 percent of the party vote will get roughly 30 percent of the seats - about 36 seats. 

How are the seats allocated?

The seats a party is entitled to from the party vote are firstly filled by its successful electorate candidates

However, if its party vote means it is entitled to more seats than those it wins through electorates, those are filled from the party's list of ranked candidates. 

Let's say a party is entitled to 36 seats through the party vote. If it wins 30 electorates, that means the six remaining seats are filled by people on its list. The person ranked highest on the list who doesn't win an electorate gets the first empty seat and so on until all allocated seats are filled.

If a party wins more electorate seats than the party vote entitles it to, there may be an overhang, which means more than 120 seats in Parliament. This doesn't affect how many seats other parties get.

A candidate who wins an electorate will have a seat in Parliament regardless of whether their party reaches the 5 percent threshold. If the candidate wins an electorate, plus their party secures, say, 3 percent of the vote, the party will still receive roughly 3 percent of the seats in Parliament despite not making it to 5 percent.