Voter enrolment

Youngest, oldest, most & least representative electorates

Wellington and Otaki.png

Thanks to the Electoral Commission for their amazing work in producing election statistics, I'm able to present a few early tidbits as I breakdown the data that's now available around the age of people who actual voted. For ease of presenting the data for the youngest and oldest electorates I've broken down age groups into the following four segments:

  • Youth vote: 18-34-years-old
  • Mortgage and Family vote: 35-49-years-old
  • Empty Nest vote: 50-64-years-old
  • Super vote: 65+

For the most representative electorates - those that from an age perspective look the most like the average of all the electorates, I've looked at the average deviation is across all of the age groups specified in the Electoral Commission's data.

I've also separated out the General Electorates from Māori Electorates for the purposes of this analysis, largely because the Māori Electorates have quite significantly different age demographics than General Electorates as you'll see below.

Oldest General Electorates
(defined by having the largest percentage of voters aged 65 and over)

Ōtaki: 40.7% (my home electorate)

Coromandel: 40.0%

Northland: 34.8%

Tauranga: 32.8%

Rodney: 32.6%

Youngest General Electorates
(defined by having the largest percentage of voters aged 18-34)

Wellington Central: 43.9%

Dunedin North: 35.9%

Auckland Central: 34.2%

Māngere: 31.3%

Mt Albert: 30.9%

Empty Nest General Electorates
(defined as having the largest percentage of voters aged 50-64)

West Coast-Tasman: 33.7%

Northland: 33.2%

Helensville: 31.6%

Kaikōura: 31.4%

Waitaki: 30.9%

Mortgage and Family General Electorates
(defined as having the largest percentage of voters aged 35-49)

Mt Albert: 32.8%

Ōhāriu: 32.0%

Kelston: 30.4%

Northcote: 30.1%

Helensville: 29.8%

Least Representative Electorates
(defined by having the largest average deviation across all age groups)

Wellington Central: Ave dev of 3.91pp

Coromandel: 3.59pp

Ōtaki: 3.18pp

Northland: 2.96pp

Mt Albert: 2.83pp

Most Representative Electorates
(defined by having the smallest average deviation across all age groups)

Christchurch East: Ave dev of 0.42pp

Port Hills: 0.44pp

Rimutaka: 0.46pp

Tāmaki: 0.51pp

North Shore: 0.58pp

Māori Electorates

Youngest - Te Tai Tonga: 36.2%

Oldest - Waiariki: 13.8%

Mortgage and Family: Tāmaki Makaurau: 31.0%

Empty Nest: Waiariki: 27.8%

Most representative: Ikaroa-Rāwhiti: Ave dev of 0.42pp

Least representative: Te Tai Tonga: Ave dev of 0.82pp

Thoughts on all of this

It wouldn't surprise anyone, but out of the youngest electorates, all but Māngere appear in the top 10 electorates for Labour growing its party vote this election (remembering Māngere is already a pretty strong Labour seat anyway). With an average representation of Youth segment voters of 22.9% across the country, Wellington Central sits at nearly double that. Coromandel, Northland, Ōtaki, West Coast-Tasman and Kaikōura had the lowest levels in the Youth vote segment.

The same isn't necessarily true the other way though. For the oldest electorates, none of the top five are in electorates where National grew its share of the party vote (the Auckland mortgage beltway), however Rodney is one of National's most valuable electorates in terms of both the share of the party vote won and the high turnout in that electorate, and the other four all did deliver higher party vote shares than National achieved New Zealand-wide.

In a similar vein to before, Wellington Central, Mt Albert, Rongotai, Māngere, and Kelston had the lowest levels in the Super voter segment.

It's also worth noting the scale of  that both Ōtaki and Coromandel had 40.7% and 40.0% respectively of voters in the Super vote segment, with Northland coming in at 34.8%, this is against an average nationally of 24%.

However all five of the oldest electorates are in New Zealand First's top 20 electorates for party vote share. No surprise there given Winston Peters' relentless courting of this demographic.

In the Mortgage and Family segment, all bar Kelston (again having a strong Labour party vote anyway) experienced above average growth in Labour's party vote, with the Empty Nest segment imitates the Super vote segment, though to a lesser extent, with only West Coast-Tasman bucking the trend. There they delivering 5pp less in the share of party vote for National, which is split over slightly above what they achieved nationally for Labour, NZ First, and the Greens. The national average for Mortgage and Family was 25.4%, and for Empty Nest is was 27.8%, so neither of these segments produced as big a gaps as the Youth or Super segments.

On the flip side, the lowest Mortgage and Family segments were to be found in Coromandel, Ōtaki, Northland, East Coast, and Dunedin North. The five lowest Empty Nest segments were Wellington Central, Maungakiekie, Mt Albert, Northcote, and Dunedin North.

When you look at the Most Representative electorates, Port Hills and Christchurch East ranked 3rd and 9th for the biggest net swings fro the centre-right to centre-left. Rimutaka, Tāmaki, and North Shore all experienced above average swings to the left too.

In terms of the least representative electorates, Wellington Central and Mt Albert both saw Labour do better than they did New Zealand-wide, with their tilt in representation being skewed heavily towards the Youth and Mortgage and Family segments. Meanwhile Coromandel, Ōtaki, and Northland where the three highest electorates for the Super vote segment, with Northland and Coromandel both being over represented by the Empty Nest segment, and Ōtaki sitting around average. As you might expect, National and NZ First did better in these electorates while Labour and the Green Party under performed in them.

With the Māori Electorates one thing really caught my attention - how heavily skewed they were towards younger segments.

This is almost certainly because the gap between Māori and non-Māori life expectancy still sits at 7.3 years as of 2013. On average nearly a third of voters in the Māori electorates are in the Youth segment of 18-34, with another 29.7% in the Mortgage and Family segment, and 26.0% in the Empty Nest segment. The Super segment (65 years and over) made up, on average, only 12.2% of voters in Māori electorates. 

Māori Electorates are also notable for being very similar to each other in terms of the age demographics of their voters. Whereas for the General Electorates the average deviation was between 0.42pp and 3.91pp, for Māori Electorates the average deviation was between 0.42pp and 0.82pp,

Greying population and youth tremor sees middle age voter squeeze

It wasn't a youthquake, but a youth tremor and a greying population have seen New Zealanders aged 35 to 54 squeezed as a percentage of our voting population.

With youth enrolments down as a percentage of the overall potential voter population this election, a youthquake was always going to be difficult. However, better youth turnout numbers than in 2014 helped counteract the significant greying of voters in those three years.

The good news is that turnout was up across the board, ranging from 6.54 percentage points for those aged 18-24 down to a 0.6pp for those aged 70+. The bad news is that those aged 18-24 made up a lower percentage of overall enrolments than they did in 2014, meaning that their big increase in turnout didn't create a significant change from 2014.

Where the big change did occur was with voters aged 25-29, who increased their representation in the actual voter pool by 0.709pp versus 2014, the largest increase of any age group. Their increase of turnout of 5.45pp, combined with their larger slice of the enrolment pie,  and to a lesser extent those aged 30-34, delivered nearly all of the increase in youth voters this election.

The increase though was largely offset by an increase in voters aged 55 and over. With voters aged 70 and over representing 0.704pp more of voters than in 2014, and those aged 55-59 representing 0.240pp more, it largely balanced out the increases in the youth voter.

All of this means that those aged 35 to 54 saw their influence as voters decrease relative to 2014, which was partially driven by their contribution to the pool of enrolled voters also dropping relative to 2014. The biggest drop was in the 40-44 bracket where they contributed 1.026pp less to the final voter pool than they did in 2014.

You can find the Electoral Commission's numbers here.

Overall there was a marginal greying of voters, going from a median age of 47 in 2014, to 48 in 2017.

And in case you're curious, here's the raw numbers.

The Greyquake, and why NZ First, and maybe National, should be plucky

Projected Voter Turnout Rates.png

Greyquake, Superquake, Pensionquake, none of those names are as catchy as Youthquake, but unless there's a dramatic turnaround in voting behaviour by younger voters, this election is set to be dominated by those with, at the very least, a sprinkling of salt and pepper in their hair.

You can see in the above graph the difference between 2014's turnout and my projections for 2017's turnout. Assuming all things remain the same from the Electoral Commissions 12 September update of enrolment data, there's going to be a noticeable shift from the youngest half of voters to the oldest half of around 4.69 points.

That might not seem like much in the scheme of things, but in an MMP environment it's a massive shift. The difference between whether a party can feasibly form a government could be decided by as little as half a percent, so to have a shift of several times that towards an older demographic in the pool of electors will undoubtedly make a different.

As I wrote earlier today, the way that enrolments are tracking suggests that for all the efforts to encourage younger voters to participate in the election, nothing is changing. What is happening those is as New Zealand's population ages, the demographic of those enrolled to vote is sharply changing in favour of those aged 55 and over. The top half of enrolled voters goes down to around the 53 mark by my maths so you could stretch it a little further if you liked.

It's also why I suspect NZ First have historically done better on election day than they have in the polls. As far as I'm aware (and please correct me if I'm wrong!) both Colmar Brunton and Reid Research both weight their poll samples to reflect the general population. However the general population, or even the number of eligible voters isn't necessarily the best way to weight your polls.

Instead your polls should be weighted to reflect the voter turnout rates from the previous election (or even averaged off the past two or three just to hedge your bets a little). With older voters making up a far larger block of actual voters, their voices suddenly matter a whole lot more come election time than they do in the general population.

Projected changes in age cohorts.png

The above graph illustrates this change even better. You can see the massive shift away from youth voters towards those aged 55 and over (though as a mentioned earlier I suspect the tipping point may be around 53 or so). These are voters who probably own houses, probably still have mortgages they're paying off, their kids have probably left home or are about to, and they're planning for retirement.

What does this mean come Election Day? Assuming that voter turnout is similar to 2014 and enrolment rates don't change markedly, it means that NZ First is going to continue on its trend of performing better in the ballot than they do in polls, and a similar effect might help National as they've been focused on eating up some of NZ First's lunch too, especially in regional New Zealand.

It'll be interesting to compare these projects with the actual statistics from the election once they're released.