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Posts Tagged ‘2011 Re-vote’

There has been a bit of hysteria the last few days about dire consequences if New Zealand First should be returned to parliament. See PM John Key on Stuff, or the Vote For Change campaign’s highly ignorable press releases, for example.

So what’s going on? A couple of recent polls have the NZF party closing in on the 5% threshold, and the probability of NZF being returned to Parliament has shot up to about 50% on iPredict, from about 15% just over a week ago.

Probability of New Zealand First being returned to parliament according to iPredict, as of evening of 20 November, 2011.

Probability of New Zealand First being returned to parliament according to iPredict, as of evening of 20 November, 2011.

On top of this, NZF leader Winston Peters has made a point of saying he won’t go in to coalition with anybody, or support anybody with supply and confidence, leading observers to assume that if NZF wins seats in parliament this election everything will turn to custard and we will be having another election in the next few months.

So what would actually happen if NZF were returned to parliament?

The current situation.

To figure this out we run a series of simulations, firstly based on the current polling avereges. We call this “Situation #0”. It looks something like this:

Histogram showing the total number of seats National are expected to win in parliament under Situation #0. National are expected to win 65.4 +/- 0.8 (RMS) seats.

Histogram showing the total number of seats National are expected to win in parliament under Situation #0. National are expected to win 65.4 +/- 0.8 (RMS) seats.

Histogram showing the total number of seats Labour are expected to win in parliament under Situation #0.  Labour are expected to win 35.4 +/- 0.8 (RMS) seats.

Histogram showing the total number of seats Labour are expected to win in parliament under Situation #0. Labour are expected to win 35.4 +/- 0.8 (RMS) seats.

Keep in mind that a party would need 63 seats to win a majority:

Histogram showing the number of seats needed to form a majority in Parliament under Situation #0. The winning party or coalition will most probably need 63 seats in Parliament to form a majority.

Histogram showing the number of seats needed to form a majority in Parliament under Situation #0. The winning party or coalition will most probably need 63 seats in Parliament to form a majority.

So National is therefore almost guaranteed an outright majority in the house:

Scenario analysis for Situation #0. The bar graph shows the probabilities for different possible outcomes for a NZ General Election.  The National Party would have a roughly 99.98% chance of governing alone, a roughly 0.02% chance of governing as leader of a National-ACT coalition, and a 0% chance of governing as leader of a National-ACT-United Future coalition. There is a 0% chance that the Maori Party would hold the balance of power in Parliament.

Scenario analysis for Situation #0. The bar graph shows the probabilities for different possible outcomes for a NZ General Election. The National Party would have a roughly 99.98% chance of governing alone, a roughly 0.02% chance of governing as leader of a National-ACT coalition, and a 0% chance of governing as leader of a National-ACT-United Future coalition. There is a 0% chance that the Maori Party would hold the balance of power in Parliament.

So there you have it.

What if NZF makes 5%?

And what would happen if NZF just makes the 5% threshold? Firstly lets simulate this by assuming that NZF takes the same number of votes from National and Labour such that they get exactly 5%. We call this “Situation #1”. Under Situation #1 NZF would win exactly 6 seats. And the other parties?

Histogram showing the total number of seats National are expected to win in parliament under Situation #1. National are expected to win 62.1 +/- 0.8 (RMS) seats.

Histogram showing the total number of seats National are expected to win in parliament under Situation #1. National are expected to win 62.1 +/- 0.8 (RMS) seats.

Histogram showing the total number of seats Labour are expected to win in parliament under Situation #1. Labour are expected to win 33.2 +/- 0.8 (RMS) seats.

Histogram showing the total number of seats Labour are expected to win in parliament under Situation #1. Labour are expected to win 33.2 +/- 0.8 (RMS) seats.

So with NZF taking 1% or so of the vote from each of National and Labour and winning 6 seats, National and Labour would respectively be 3.3 and 2.2 seats worse off. The fallout is not just limited to those two parties either; the Greens, for example, would be 0.5 seats worse off. And who would form the government?

Scenario analysis for Situation #1. The bar graph shows the probabilities for different possible outcomes for a NZ General Election.  The National Party would have a roughly 25.1% chance of governing alone, a roughly 70.5% chance of governing as leader of a National-ACT coalition, and a roughly 4.1% chance of governing as leader of a National-ACT-United Future coalition. There is a 0.3% chance that the Maori Party would hold the balance of power in Parliament.

Scenario analysis for Situation #1. The bar graph shows the probabilities for different possible outcomes for a NZ General Election. The National Party would have a roughly 25.1% chance of governing alone, a roughly 70.5% chance of governing as leader of a National-ACT coalition, and a roughly 4.1% chance of governing as leader of a National-ACT-United Future coalition. There is a 0.3% chance that the Maori Party would hold the balance of power in Parliament.

So if NZF takes votes off National and Labour equally and makes the 5% threshold there is a much reduced chance of National getting a majority, but we would still have a National Prime Minister. Winston Peters wouldn’t be in a position to force another election.

What if the votes come exclusively from National?

And what would happen if NZF just makes the 5% threshold, and takes their extra votes exclusively from current National supporters. We call this “Situation #2”. Under Situation #2 NZF would still win exactly 6 seats, and National would be as follows:

Histogram showing the total number of seats National are expected to win in parliament under Situation #2. National are expected to win 61.2 +/- 0.8 (RMS) seats.

Histogram showing the total number of seats National are expected to win in parliament under Situation #2. National are expected to win 61.2 +/- 0.8 (RMS) seats.

Scenario analysis for Situation #2. The bar graph shows the probabilities for different possible outcomes for a NZ General Election. The National Party would have a roughly 4.4% chance of governing alone, a roughly 69.6% chance of governing as leader of a National-ACT coalition, and a roughly 21.1% chance of governing as leader of a National-ACT-United Future coalition. There is a roughly 5.0% chance that the Maori Party would hold the balance of power in Parliament (with a National-coalition advantage).

So if NZF takes votes solely off National and just makes the 5% threshold there is a much reduced chance of National getting a majority, but we would still most likely get a National Prime Minister, even without taking the Maori Party into consideration. Winston Peters almost certainly wouldn’t be in a position to force another election.

What if NZF makes 7%, and the votes come exclusively from National?

Now lets assume that NZF wins exactly 7% of the vote, with their extra votes coming exclusively from current National supporters. We call this “Situation #3”. Under Situation #3 the results would be as follows:

Histogram showing the total number of seats NZF are expected to win in parliament under Situation #3. NZF are now expected to win 8.7 +/- 0.4 (RMS) seats.

Histogram showing the total number of seats NZF are expected to win in parliament under Situation #3. NZF are now expected to win 8.7 +/- 0.4 (RMS) seats.

Histogram showing the total number of seats National are expected to win in parliament under Situation #3. National are expected to win 58.6 +/- 0.7 (RMS) seats.

Histogram showing the total number of seats National are expected to win in parliament under Situation #3. National are expected to win 58.6 +/- 0.7 (RMS) seats.

Scenario analysis for Situation #3. The bar graph shows the probabilities for different possible outcomes for a NZ General Election.  The National Party would have a 0% chance of governing alone, a roughly 0.4% chance of governing as leader of a National-ACT coalition, and a roughly 4.5% chance of governing as leader of a National-ACT-United Future coalition. There is a roughly 95.5% chance that the Maori Party would hold the balance of power in Parliament (still most likely with a National-coalition advantage).

Scenario analysis for Situation #3. The bar graph shows the probabilities for different possible outcomes for a NZ General Election. The National Party would have a 0% chance of governing alone, a roughly 0.4% chance of governing as leader of a National-ACT coalition, and a roughly 4.5% chance of governing as leader of a National-ACT-United Future coalition. There is a roughly 95.5% chance that the Maori Party would hold the balance of power in Parliament (still most likely with a National-coalition advantage).

So even under the rediculously optimistic scenario of NZF doubling their current support in the next six days, with the new support coming solely off National, the Maori party would still most-likely hold the balance of power in parliament.

And what would the Maori party do? Coalition with National, ACT and United Future? Or coalition with Labour, Greens, Mana and New Zealand First? Even assuming that the latter four parties were all on the same page (unfeasible, given recent statements from their leaders), would the Maori party favour them? Not likely if a three-party right-wing coalition had a numbers advantage over the four-party left-wing coalition. It would be far too easy (politically) for the Maori Party to go into a right-wing coalition, and extract some fairly heavy concessions whilst doing so.

Conclusion.

So, in summary, even if NZF win 7% of the vote, which is unlikely on current polling, the chances of them holding a balance of power and forcing another election are effectively zero. Anybody who suggests otherwise is just being a bit hysterical.

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