New Zealand election 2017: Poll of polls shows tight race
Today, Stuff launches a new 'poll of polls' tracking the race to election day. It is the first in a series of features to appear on our election dashboard, which will show live results as they are known on September 23.
In consultation with Massey University, we have devised a new method for measuring polling. The Stuff poll of polls differs from others by giving weight to each poll based on how recent it is. We do not use internal party polling.
So what does it show?
Until the latest Roy Morgan poll earlier this month, National would have held power without the need for any new coalition partners - just.
But National fell back slightly in that poll, dragging its support down to 46 per cent, which would translate into 56 seats in Parliament.
National could rely on another four seats from the Maori Party, ACT and UnitedFuture assuming the leaders of those parties hold on to their electorate seats - Te Ururoa Flavell in Waiariki, David Seymour in Epsom and Peter Dunne in Ohariu.
Flavell would bring another MP into Parliament for the Maori Party on current support.
That would give a National-led group of 60 MPs - an agonising one seat short of a majority in a 121-seat Parliament (there would be an overhang of one seat).
Then what? You guessed it, Winston Peters and NZ First hold the balance of power.
The poll of polls suggests NZ First, with 12 seats, would effectively decide the Government.
If they were to throw their lot in with Labour (28 per cent of the vote, 34 seats) and the Greens (12 per cent, 15 seats) that centre-left bloc could form a Government with a slim one-seat majority.
Although Peters appears well-placed, the poll of polls also shows that a modest improvement in support for National could still cut him out of the picture.
HOW OUR POLL OF POLLS WORKS
The Stuff poll of polls is an average of the most recent of each of the public political polls in New Zealand. Currently, there are only three: Roy Morgan, Colmar Brunton and Reid Research.
When these companies release a new poll it replaces their previous one in the average.
The Stuff poll of polls differs from others by giving weight to each poll based on how recent it is.
All polls less than 36 days old get equal weight. Any poll 36-70 days old carries a weight of 0.67, 70-105 days old a weight 0.33 and polls greater than 105 days old carry no weight in the average.
No internal party polling is included in the average.
The poll of polls was developed with help from Professor Malcolm Wright of Massey University.