Guest Post: Read This One Post To Understand MMP Better Than A Political Science Professor

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Whatever your personal views on , the referendum result in 2011 made it clear that our electoral system is here to stay for the foreseeable future.

MMP is exceedingly complicated.

I spent a large chunk of time during my political science degree at Victoria University learning it intimately, and still have to look things up occasionally to make sure I’ve got them correct.

While many people now understand that the Party Vote is the most important vote in deciding the makeup of the legislature, the intricacies of overhangs, top-up seats and the Saint-Lague formula are lost on most people.

It’s common to see mistaken or just plain wrong comments on news media websites and blogs and that’s fair enough really.

No one actually needs to understand the Saint-Lague formula in their daily lives, and putting in the required effort to properly comprehend it would be a complete waste of your time.

Unless, that is, you want to take on the responsibility of explaining the system to others, whether in day-to-day conversations, as a commentator in the media, or as an academic in the classroom.

Which brings us to Q&A on Sunday, and the comments of one of their guests, which provide an excellent opportunity for a refresher course for anyone interested.

Raymond Miller has a doctorate in political science, has written a book about our political party system, served as the head of the Political Science department at Auckland University, teaches courses on elections and is conducting research in to electoral systems.

And yet, he seems to have absolutely no clue about how MMP works, and why the Epsom electorate is so important in this and previous elections.

On the show, Dr Miller claimed that if David Seymour won Epsom but ACT didn’t win enough party votes to bring in extra MPs, then National would have been just as well off with Paul Goldsmith winning the seat.

But this is just completely, objectively, factually wrong.

I hope with this post, I can clear up some of the confusion.

By now, no-one out there should be in any doubt that if ACT receive enough votes to elect extra MPs with David Seymour, then that is extra MPs for the centre-right, obviously.

But what about the scenario that Raymond Miller suggests of ACT not getting anyone other than David Seymour elected?

There are two possible ways this could happen:

Scenario 1) If David Seymour wins Epsom, but ACT receive between 0.0% and ~0.4% of the vote.

In this situation, David Seymour would be what is referred to as an “overhang” MP.

This means that ACT won more electorates than their party vote entitles them to.

This also happened to the Maori Party in 2011.

The Maori Party won 3 electorates, but only received enough party votes to be eligible for 2 seats in parliament.

In these kinds of situations, rather than saying that someone who won an electorate may not sit in Parliament, sensibly, the overhang MP is still elected to parliament.

The size of parliament is actually temporarily increased to 121 MPs, meaning the Maori Party received their 2 seats according to their party vote, and then one extra seat for their third electorate MP.

So even if ACT receives so few votes that David Seymour is an overhang MP, the centre-right still receive a whole extra 1 seat.

[Note: If there are two overhangs in a parliament, meaning there are 122 MPs, then 62 votes would be needed to form a government instead of 61 votes, but even under this unlikely scenario, David Seymour would still effectively count as an extra 1/2 seat for the centre-right.]

Scenario 2) If David Seymour wins Epsom, and ACT receives more than ~0.4% but less than ~1.2%.

In this situation, ACT receive enough votes that David Seymour won’t be an “overhang” MP, but not enough to elect a second MP.

This is where MMP starts to get really complicated.

To explain, let’s start with a background on how seats are allocated under MMP.

The number of seats a party receives in parliament is determined almost entirely by the party vote they receive, according to the Saint-Lague formula. 

Typically, parties win a large enough party vote to entitle them to more seats in parliament than the number of electorates they win.

For example, in 2011, National received 47.31% of the vote, entitling them to 59 seats in Parliament.

National candidates won 42 electorates, which was then topped up with 17 list MPs to ensure National had the 59 MPs they deserved.

Had Paul Goldsmith won Epsom in 2011, National would still only be entitled to 59 seats in total, as their party vote hasn’t changed, but would now hold 43 electorates, meaning the number of top-up electorate seats they would receive would simply be reduced to 16.

So, Paul Goldsmith winning Epsom would have cost ACT a seat, but not gained National any extra MPs – result: one fewer MP for the centre-right.

But where did that ‘spare’ seat go?

As ACT wouldn’t have won an electorate seat, ACT’s votes would now be wasted votes, and this would change the Saint-Lague calculation.

It is technically possible that the election’s party vote result could fall in such a way that during the calculation, the Saint-Lague formula determines that National receives this ‘spare’ seat.

But it’s much more likely that the ‘spare’ seat is awarded to Labour, or the Greens, or New Zealand First, leaving the centre-right with one fewer seat, and the centre-left with one more.

This is exactly what would have happened had Paul Goldsmith won Epsom in 2011, as the Saint-Lague formula would have awarded the ‘spare’ seat to Labour.

You can see for yourself using the Election Commission website’s Saint-Lague calculator:

http://www.elections.org.nz/voting-system/mmp-voting-system/mmp-seat-allocation-calculator

Just load in the 2011 election results, but change ACT to have won 0 electorate seats, and National to 43.

ACT drops from 1 to 0 seats, National stays on 59 seats, and Labour increases from 34 to 35.

On that result, the Labour, Greens, NZF, Mana and Maori Parties would have had enough seats to form a government.

It’s possible the Maori Party might have chosen to continue working with National.

But then, rather than John Key being able to pass legislation with UF and ACT or with the Maori Party, National would have needed both United Future AND the Maori Party’s votes on every single bill in parliament.

The Maori Party would have held the balance of power on every single vote.

It’s not merely an exaggeration that ACT winning Epsom in 2011 decided the entire election.

If you know any Epsom voters, show them this article, and make sure they understand they might also decide the 2014 election.

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