Youngest, oldest, most & least representative electorates

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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,